February 26, 2026 • 50 mins
This week, Emily and Perry plunge, as it were, into the temperature extremes: cold plunges and saunas. Is there any actual value to shocking your body with ice water or sweating out an ocean? Or are we just gluttons for punishment?
Plus: soaring measles rates, Jay Bhattacharya's double federal appointment, and pandemics lurking under the ice.
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Episode Transcript
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Speaker 1 (00:02):
Emily, I have an audio challenge for you. Are you ready,
I'm ready, Okay. I want you to listen to this
following clip, and your job is just to tell me
what's going on here. I don't know if I could
do this. However, it is a countdown.
Speaker 2 (00:25):
Countdown, So Perry, I think this is going to reveal
too much about my Internet consumption. But I think that
I have seen the video associated with that audio on
TikTok wow, and that person is cold plunging in an
icy lake.
Speaker 1 (00:46):
I believe I have once again underestimated your ability to
understand the Internet zeitgeist. Emily. You're correct, that is not
a lake. It is a tub of some kind that
is filled with icy water. But I will say that,
being new to exploring the world of social media wellness
influencers and looking at a bunch of cold plunge of videos,
(01:09):
this is what I took home was this seems terrible.
No one enjoys this.
Speaker 3 (01:18):
I agree.
Speaker 2 (01:19):
I think that if there are any benefits, it is
that you are just so happy to be out and
not dead that everything about your life after that seems
better because you are not in an ice pit.
Speaker 1 (01:31):
There's no joy without sadness. Perhaps that is the philosophy
of cold plunges. This week, we're going to explore extreme
cold temperatures on your body as well as hot temperatures
on your body in the form of Sauna's two ends
of a bipolar system of stressing the body with temperature.
We'll figure out if the data supports whether these things
are beneficial or not. Should we dive in?
Speaker 3 (01:52):
We should dive in.
Speaker 2 (01:56):
I'm Emily Oster, I'm an economist and a data expert.
Speaker 1 (02:00):
I'm Harry Wilson, I'm a medical doctor.
Speaker 2 (02:02):
It's Thursday, February twenty sixth twenty twenty six, and this
is wellness actually.
Speaker 1 (02:07):
Because you're getting a staggering amount of health and wellness
information nowadays from every source imaginable, and some of it
is awesome and.
Speaker 2 (02:16):
Some of it is well actually both. Fortunately we are
both people who know how to read studies, how to
parse the data, and can tell you what's worth thinking about.
Speaker 3 (02:27):
And what you can safely ignore.
Speaker 1 (02:29):
But before we dig in, a note that this podcast
is for educational purposes and should not be construed as
medical advice. We don't know your unique situation, so talk
to your doctor for personal health decisions.
Speaker 2 (02:40):
This week, we're asking what's the deal with cold plunges
and saunas? And then we'll get to your question of
the week, But first let's do the health news roundup
after the break.
Speaker 1 (03:01):
Now onto the health news of the week, Emily, I'm
looking at CDC dot gov measles numbers through last week.
Through February thirteenth, there have been nine hundred and ten
total cases to date this year twenty twenty six in
the United States. There were twenty two hundred and eighty
in all of twenty twenty five last year. If you
(03:24):
do the math, we're at about three times higher than
twenty twenty five, which was a particularly bad year to
begin with their measles outbreaks in the majority of states.
What are you taking home from the new data?
Speaker 2 (03:40):
The measles data is really pretty scary.
Speaker 3 (03:44):
I mean, I think it's worth saying.
Speaker 2 (03:47):
You highlighted that we are saying more cases than twenty
twenty five. Let me give you a what I think
is a sharper fact, which is that in a single
week in January of this year, we had more measles
cases than all but a small hand full of years
over the past three decades. And so really this is
an unprecedented set of outbreaks.
Speaker 3 (04:08):
We are likely to continue seeing them.
Speaker 2 (04:09):
So those numbers that you gave go through the sort
of second week of February already. Since those there have
been announcements of a reasonably large outbreak at a college
in Florida, announcements of the beginnings of an outbreak in
Salt Lake City. So we're going to start seeing more
of this around. And it is happening for a very
basic reason, which is that measles is super contagious. It
(04:33):
can live for a very long time on surfaces. So
one number is probably useful to put out there is
when we talk about diseases in their contagiousness, we talk
about a number called are not which is like how
many people someone is expected to infect if we kind
of had a totally disease naive population. And so for measles,
that numbers estimated to be sort of somewhere in the
(04:54):
range of like twelve to eighteen. So every case of
measles infects another twelve to eighteen p Well, by contrast,
for a number like flu, it's a little bit above one,
maybe maybe sort of one to two. And so this
is just so contagious and when it faces a population
with lower vaccination rates, which is what we have, a
lot of people are going to get measles, and that's
(05:15):
just kind of what's going to happen.
Speaker 3 (05:17):
That's it.
Speaker 1 (05:18):
Yeah, there's really no reason to get measles. That's that's
the thing that I keep coming back to. I see
these stories of kids who've been hospitalized. A couple of
children died last year. You know, you can read the
statements from families by and large, who even in the
face of this, will often say things like, you know,
I don't regret the choices I made, and I understand
(05:39):
there's some self defense mechanisms at play here, but just
to say it out loud, like measles is one of
those things that we have defeated by and large, like
we won this particular battle. There's no reason to keep
fighting it.
Speaker 2 (05:51):
Yeah, I mean, I think it's just it's just very
sad to say, you know, children will die this year measles.
Measles mortality rates something like one in a thousand, so
there will be kids this year.
Speaker 3 (06:01):
Who will die of measles who could have not died.
Speaker 2 (06:05):
And I think when you put it like that, it's
just that's just really sad.
Speaker 3 (06:09):
That's all. Yeah, it's really sad. Okay.
Speaker 2 (06:13):
Moving on to some appointment news in the federal government.
So j Badicharia, former professor at Stanford, economist and doctor.
Speaker 3 (06:24):
So he's like both of.
Speaker 1 (06:25):
Us, the perfect mix of you and I.
Speaker 2 (06:29):
I'm sure he is in charge of the NIH and
has now been named as the acting director of the CDC.
Jay is known for many things, but one of them
is during COVID, he was one of the authors of
the Great Barrington Declaration, which in the fall of twenty
twenty argued for a more focused approach to COVID, which
would have protected the elderly but allowed COVID to spread
(06:51):
more widely among healthy people. You got a lot of
attention and hate for this at the time. He has
now been put in charge of not one, but two
major parts of the federal disease infrastructure.
Speaker 1 (07:02):
Your thoughts, including the part of the federal disease infrastructure
that's responsible for containing outbreaks of disease, just to say it. So,
let me take issue with one thing you said about
the Great Bearrington Declaration, which, as you said, it would
have protected older people and let the virus sort of
spread throughout you know less vulnerable populations. That was the pitch.
(07:23):
I think the reality is protecting older people. You can't
just say like, oh, we will protect people. You have
to actually demonstrate it, and as all outbreaks have shown us,
it's really hard to do that, Like do you try
to isolate people? Are you sliding food under the doors
of older people's homes and so on and so forth.
So you know, I don't think the Great Bearrington Declaration
(07:44):
was well thought out. It was primarily ideological, and that
seems to be the way this administration works is that
they pick an ideology that they favor, and they put
people in charge of the scientific apparatuses who believe in
that ideology as opposed to people that are behaving like scientists,
which is to look at data and to derive conclusions
(08:07):
from the observable data.
Speaker 2 (08:09):
Let me say one thing here where so I know
Jay pretty well, and he is a very smart guy
who you know, getting back to our measles discussion, I
think does fundamentally believe in routine childhood vaccinations, and if
you asked him, would say people should get the measles vaccine.
(08:29):
So I have what is presumably a somewhat naive hope,
but I do think that relative to some of the
vaccine rhetoric that we're seeing coming out of the administration,
this is a more evidence based voice on some of
these pieces. I'm a little worried that the job of
being both in charge of the NIH and in charge
(08:50):
of the CDC is just too much job for a
single person, even an economist.
Speaker 3 (08:54):
It is.
Speaker 1 (08:55):
It is a big job. I hope you're right. I'm
not going to hold my breath. I think what I've
seen from even very smart people in this administration, and
I know some of them too, although I don't know
Jay is a tendency to cave to the political wins
as opposed to the scientific evidence. But we'll see.
Speaker 3 (09:13):
I guess we'll find out.
Speaker 1 (09:15):
Speaking of terrible pandemics that may imminently sweep the nation,
I'm wondering if you saw this article about a five
thousand year old bacteria that was discovered in an ice
cave in Romania that just so happens to be resistant
to like all modern antibiotics. So, like I've read this book,
(09:37):
I'm pretty sure I think we all turned into zombies
in the next sixteen to ninety days.
Speaker 3 (09:41):
Big Michael Crichton wrote like nine versions of this book.
Speaker 1 (09:45):
Yeah, yeah, all great.
Speaker 2 (09:46):
This is published in a Frontiers journal. So the discussion says,
this bacteria SC sixty five a dot three sounds like
a peptide, represents an ancient ice adapted psychic bactor with
a dual profile of multi drug resistance and antimicrobial activity,
highlighting ice caves as under explored reservoirs of ancient resistomes
(10:09):
and bioactive traits.
Speaker 3 (10:10):
I felt like when I read that, I was like, man,
let's maybe not.
Speaker 2 (10:13):
Explore more, maybe over explored more or less leave the
ice caves where they are. So is I mean, realistically,
should we be concerned about ancient bacterias coming out of
the explored ice caves.
Speaker 1 (10:27):
I think there's a theoretical concern. The authors actually in
that paper they're quite positive. They're like, oh, we can
learn new ways that bacteria develop antibiotic resistance that we
hadn't thought of, and thus we can create new antibiotics.
So there's always there's always value here. You do have
to be careful. I mean, the truth is that there's
permafrost all over the Earth that contains ancient organisms, some
(10:50):
of which are capable of infecting humans, and some of
which haven't infected humans for thousands of years, but nevertheless
can persist under the ice, and some of that ice
receding right as the as the climate warms, and so,
you know, there are a lot of ways that new
pathogens can get into the human population. The most common
is we, you know, invade the territory of some animal
(11:11):
that we haven't had a lot of interaction with, and
some virus in that animal or vectory, and that animal
hops into humans. That's, you know, probably what happened with
All the Stars viruses like COVID and any number of others,
as well as several Michael Crichton books. But you know,
ice ice melting is another potential vector here. It's definitely
something that we should be aware of, but probably not
(11:32):
freak out about.
Speaker 3 (11:33):
Okay, I think that's it for the health news.
Speaker 2 (11:35):
I feel like next week we need to go have
more Olympics because I miss the discussion of condoms.
Speaker 3 (11:40):
I would rather discuss Olympic condoms.
Speaker 1 (11:42):
We could discuss. We should kind of have a running
like how many condoms have they used now? And let's
just have that number exponentially rising, I assume as we
get closer to the end.
Speaker 2 (11:51):
So with that first a break and when we come back,
cold plunges and saunaus.
Speaker 1 (12:02):
All right, we are back, and it's time to talk
about your hot and your cold. You know, Katie Perry
is on my mind this week because we're talking about
cold plunges and saunas. Both of these things are all
over the wellness space. You've got promoters on all sides.
As I've explored this, I've seen people making claims from
(12:26):
the idea that they're a nice way to relax after
a workout, to they will improve diabetes control. I mean,
it is all over the map. Lots to dig into here,
but Emily, before we get started, I feel like we
need to just kind of define our terms. Can you
walk us through, like what is a cold plunge? What
is a sauna? All right?
Speaker 2 (12:46):
So generally, and I will say, part of what's hard
about this space is that this is not well defined
because really we're talking about a lot of things, many
of which are done in the wellness space, which is
an unregulated vague.
Speaker 3 (13:00):
But when people talk about.
Speaker 2 (13:01):
Cold plunges, they are generally referring to being in a
some body of water largely submerged for an amount of
time that varies from like I jumped in the water
and I got immediately out to sitting for you know,
five or ten minutes. The water is generally extremely cold,
(13:24):
typically ice icy. Often people will do this and the
like low budget version of this. This guy, I've got
like a giant backyard like metal tank, and then my
Instagram video will have me walking out and like cutting
a hole in the ice on the top of my
tank and then getting into it, often with my husband
or wife, so we can have a romantic popsicle.
Speaker 1 (13:47):
Worst date night ever, worst date ever.
Speaker 3 (13:50):
But anyway, so that's so it's very very cold. Of
course they also make like.
Speaker 2 (13:54):
More expensive tubs that will regulate this temperature for you.
But it's very cold relatively short period of time. Then
there's a sort of hot side of this, which actually
is quite a bit more varied. So you can be
hot in a sauna, or you can be hot in
a hot tub, or actually in sports, you can be
hot in like exercising in like a winter coat.
Speaker 1 (14:16):
Oh yeah, and like hot yoga. Right, I mean, I
guess that's a sauna, right.
Speaker 2 (14:21):
Sua, although it's not like a dry son it and
in fact, if you get.
Speaker 3 (14:25):
Into like the Fins.
Speaker 2 (14:26):
A lot of the data on saunas from people in Finland,
and the Fins have like a lot of really specific
things about their saunas, like different kinds of saunas.
Speaker 3 (14:34):
The saunas are the rocks, the saunas without the rocks,
I don't know.
Speaker 2 (14:37):
At any rate, you are quite hot for a period
of time, and typically a bit longer. So sauna or
hot tub exposure is often something like a half an hour,
you know, longer in the hot tub than than in
the sauna, And the idea is just to raise your
to raise your body temperature for.
Speaker 3 (14:53):
Some extended period of time.
Speaker 2 (14:55):
So basically we're talking about being either very cold or
very hot. I think it's just worth saying both of
these are uncomfortable. So we're talking about not like a
relaxing bath with candles. We're talking about like most people
do not enjoy being in a hot tub for thirty minutes,
especially since in the heat treatments usually you have to
(15:16):
have your arms in, so you're just really hot.
Speaker 3 (15:19):
Like it's just like really hot and uncomfortable, or really
cold and uncomfortable.
Speaker 1 (15:24):
But but if I had a nice finished sauna in
my office right here, and a giant bathtub full of ice.
You ask me which one I'd rather spend fifteen minutes,
and I'm taking the sauna every day of the week.
Speaker 2 (15:37):
Just going to say it, I think that's right. I
hate being both hot and cold. I just I like
to be one intermediate temperature that's perfect. I find both
of these ideas like almost unbearable.
Speaker 3 (15:49):
But I do think I would also.
Speaker 2 (15:50):
Choose hot, although last time I was in a sauna,
I literally made it forty five seconds before I was like,
oh my god, I have to leave.
Speaker 3 (15:57):
I'm going to die.
Speaker 1 (15:58):
Okay, Oh you're okay. So you're really like your your
homeothermia or whatever, meaning yeah, sure, regular persones somewhere somewhere
in the middle. But if there are real health benefits, right, like,
maybe it's worth it. Maybe what I think we need
to figure out.
Speaker 2 (16:12):
All right, let's before we figure out the health benefits, though,
let's talk a little bit about like why these might matter.
Like what's the physiology, So you're the doctor, what is
the physiology of these kinds of exposures to extreme temperatures?
Speaker 1 (16:26):
Sure, and let me say like a little bit of
philosophy of wellness here where I think this might be
a recurring theme in our podcast, which is that in
medical science we start with this concept called biologic plausibility,
which is is it possible that this thing works? Not
does it work? Just like does it make sense? You know,
(16:47):
if someone came and said eating red jelly beans cures cancer,
I would say there's no biologically plausible way that that
is true. It's not really worth your time. Where I
think wellness gets it wrong is that they stop there
say like, oh, it's plausible and therefore it does. And
where we need to go is like, Okay, maybe it's plausible,
but like does it actually And there's there's a wider
(17:09):
gap between plausible and reality than people often think. So
let's first of all, just talk about biologic plausibility. The
physiology of cold water plunges is pretty interesting and we
have a good amount of data on this, believe it
or not, because the military is really interested in what
happens to people when they drop into cold water. This
(17:30):
is something I guess that we do. We probably do
it more often than we know that we do. And
so the Department of Defense has funded quite a few
studies exploring like the short term and medium terms effects
of these cold water plunges. It's not exactly the same
as you know, calmly getting into ice water in your backyard.
But there's a very standard physiologic response called the cold
(17:52):
shock response, which is well described, which happens in the
first thirty to ninety seconds of getting submerged in cold
water at about forty degrees already five degrees or less,
and it is essentially involuntary. It is characterized by a
deep and rapid intake of breath, like a feeling yeah,
(18:12):
and that's about three liters of air intake. And just
to put it in context, breathing kind of normal like
in and out is you know, maybe a leader in
and out of air intakes, so you're really this very
deep breath and this is actually when people fall through
the ice or something. This response is what results in
a lot of drowning because if your head's underwater and
you do that, you just suck in a ton of water,
(18:34):
it can be very dangerous. You get this dramatic again
first thirty ninety seconds, a dramatic increase in the sympathetic
nervous system. This is that fight or flight response, which
is going to increase your heart rate, your blood pressure spike,
your cortisol levels. It increases adrenaline levels by a factor
of about five. In these studies, your adrenaline just goes
(18:55):
through the roof in those sixty minutes. Interestingly, dopamine level
increase bye two and a half fold. So we often
think of dopamine as sort of like a feel good chemical.
But you've got a lot of a lot of chemistry
going on in that first minute in the ice, and
it's obviously not entirely pleasant.
Speaker 3 (19:14):
What was the pleasant part the dopamine? Oh, the dope
mean the don't mean that's going up? But is the
dopaine going up? So your body is convinced, like, don't
just die right now? Things could improve the next ninety six.
Speaker 1 (19:27):
Yes, we call it hopamine. It's like, uh, I'll give
you a hug and then slap you in the face
as hard as I can. I don't know, it's not great.
I just want to give the good in the bad. Okay.
Vaso constriction So when you get cold, your superficial blood
vessels constrict to reduce heat loss to the environment, so
blood gets shunted away from your skin and potentially your muscles.
(19:48):
I think we need to get into this a little
bit to your central organs, which are the things that
really need to keep you alive, so like your heart
and your brain and your kidneys. To some extent, it
also makes you have to pee, and as a kidney doctor,
we see this non frequently in the hospital. So after
someone has a traumatic brain injury or a stroke, if
we catch them in time and they're in very severe cases,
(20:09):
we will induce hypothermia. There is some data there for
brain injuries that recovery is better with hypothermia, and we
do see that as you reduce their body temperature of
the year, an output goes up because blood is getting
shunted away from the periphery and into the kidneys. So
if you jump in that cold plunge pool and then
you have to get right out to pee, that's a
great excuse. One last thing on physiology, because this is
(20:33):
something that's actually potentially dangerous with cold plunges, and that
is the mammalian diving reflex. This is a thing that
happens when you submerge your face in cold water. It
basically is an evolutionary artifact of our instinct to change
our physiology when we're swimming, or especially when we're going
(20:54):
deep underwater. What happens in the mammalian diving reflex again
only if you put your face in the water, is
your heart rate goes down. It sort of slows your metabolism.
And this is potentially a problem because the cold shock
response makes your heart rate go up, the mammalian diving
reflex makes your heart rate go down, and there is
some evidence that those conflicting signals can precipitate a cardiac arrhythmia,
(21:20):
and people have died within the first couple of minutes
of a cold plunge potentially through this mechanism.
Speaker 3 (21:26):
So don't put your face in the water.
Speaker 1 (21:27):
Don't put your face in the water. Like I saw
on a lot of the tiktoks, is like okay, you're in,
like now, go all the way and like probably not
actually certainly not in the first couple of minutes while
you still have the cold shock response going on. So
that is the cold side of things.
Speaker 3 (21:43):
Okay, it sounds terrible. Tell me about being hot.
Speaker 1 (21:47):
Okay, the warm side I think is a little bit better.
So what happens when you're exposed to heat is that
your body does stuff to reduce your body temperature. And
the thing it does is it dilates blad vessels in
your skin so that more blood gets to the skin
the surface areas, you can exchange heat better with your environment,
and then you do this amazing thing that humans are
(22:08):
very proficient at, which is that you sweat. And so
one of the reasons those finish saunas can get to
such a higher temperature than the steamy saunas is because
you have evaporation of sweat, which is cooling you off,
whereas if you're in steam, your sweat won't evaporate, So
people can tolerate the finish saunas quite a bit better.
(22:30):
Because of sweating, you can lose a lot of water
through sweat, though you can put out leaders of water
in a hot enough sauna you spend enough time there,
so dehydration is certainly something to think about. There have
been some studies that show that that warmth does release
some endorphins, which are sort of you know, endogenous feel
good chemicals. So taken all together, it's not as like,
(22:54):
oh my god, I'm about to die as a cold plunge,
but still might not be pleasant for you. Emily. All right, okay,
so now we know what happens, right.
Speaker 3 (23:04):
Question is whether it's important.
Speaker 1 (23:06):
Whether it's helpful biologic plausibility wise, there's something here. It
does something right. Maybe increasing your part rate is good.
It's like a little exercise, you know, vasodilation, phasoconstriction. You
could make arguments that these are good things, but we
really need to figure out like, okay, are they good things?
And I think where ice has got its most data
(23:28):
emily is for athletes, right, like particularly like athletes who
are really doing endurance stuff. Can you tell me about that?
Speaker 3 (23:36):
Yeah?
Speaker 2 (23:37):
So I think both ice and heat are things that
people who are doing like serious sports try to experiment with.
Speaker 3 (23:43):
And I think we sort of start with ice.
Speaker 2 (23:45):
The idea again to get to the biological plausibility issues.
The idea behind ice is sort of similar to, like
I have an injury I have which partly is inflammation.
You ice your injury. That's like a well known approach
to prevention. I think there's a kind of extension into
the sort of cold plunges in icing, which is like,
well maybe if I just iced my whole body, that
(24:08):
would like lower my inflammation overall, and it might improve
recovery and ideally improved performance. I mean, I think part
of what's I guess is we'll talk about this a
lot of them podcasts, But there's actually a lot more
research on a lot of these topics in athletes than
there is in other people, in part because it's a
very easy population to study, because you know what you're.
Speaker 3 (24:27):
Trying to achieve and it's short term.
Speaker 2 (24:29):
Right, So you can say, Okay, I'm going to put
people in this protocol, dump them in the ice after
their you know, cycling test, you know, every day for
three weeks, and then I'll do it not for three weeks,
and I'll measure their VO two max on a special bike.
Speaker 3 (24:41):
And blah blah blah.
Speaker 2 (24:42):
And it's like just much easier to think about what
you're trying to accomplish and how to measure it.
Speaker 3 (24:46):
Yeah, and so many of.
Speaker 2 (24:47):
The problems we have studying regular people is what we're
trying to say is like do you live to be
one hundred? And like I can't measure that three weeks
from now, obviously exactly, So I will say when we
look at ice, my sense of the literal sure is
that it's really not that great that these cold plunges.
Maybe they have you know, a little bit of an
(25:08):
impact on sort of subjective muscle soreness. But in terms
of recovery and performance and so on, there just isn't
much consistent evidence that these things matter.
Speaker 1 (25:19):
A lot of the studies have this.
Speaker 2 (25:21):
Feature that it's like, well, we did this and we
looked at these you know, forty seven different outcomes and
you know, three of them it mattered, and it's like, yeah,
but that's actually not a very statistically robust result. So
I for me, the like ice for athletes is a
bit of a dud.
Speaker 1 (25:38):
Yeah, I you know, as I was looking into this,
I sort of assumed that at least for the real
you know, real athletes, right, like the professional athletes, because
you see these like the football players and the baseball
players with the professional trainers and everything like, and they
have these ice bats in the training house. And I
saw enough videos of professional athletes like talking about the
(26:00):
process before they get into the ice bath, like what
they have to go through mentally and physically. You know,
they're like, okay, I've got it because they hate it, right,
Like they've got a mentally prepare Like some of them
are drinking really hot tea. They're putting on like rubber
gloves and boots and things like that. So that they
don't get like a schemia of their digits and things.
(26:20):
And then they you know, they get in and it
has this feeling like, well, it must be really beneficial
because they're they're putting themselves into this and and you're right,
you know. Looking at the data, I couldn't find much.
I found one study that looked at the level of
a substance called creatine kinase, which is a muscle enzyme.
(26:41):
It goes up when you work out really vigorously because
you do damage muscles when you work out hard. In fact,
that's the way your muscles get bigger, is that you
sort of damage them and then they get they come
back stronger, and so CK levels go up after exercise,
and the people that they randomize to do the ice
bath it didn't peak quite as much. But I'm not
(27:01):
sure that means that, like that's even better for you, right, Like, yeah,
don't you kind of want some muscle damage? I mean
that's right, Like if you're trying to build muscle, I.
Speaker 2 (27:09):
Mean, yes, you do need to damage your muscles to
try to build them. But I think the more generally,
like where's the where's the performance out come?
Speaker 1 (27:15):
There?
Speaker 2 (27:15):
You know, this is like we're measuring all of these
things and like we don't really we don't have a
great sense of that that translates into performance. And I
think if you look at this sort of true performance stuff,
being cold is just we just don't have like a
lot of good evidence.
Speaker 1 (27:29):
All right, professional athletes take notes.
Speaker 2 (27:31):
On the other hand, I will say I think the
evidence on heat in sports is somewhat more compelling.
Speaker 3 (27:38):
The typical protocol.
Speaker 2 (27:40):
Here is hot tub, so basically taking people in after
their workout, putting them in a hot tub for thirty minutes.
Speaker 1 (27:46):
This is literally the opposite of what we just talked about.
So I feel like both of these can't work.
Speaker 3 (27:51):
People don't like this either.
Speaker 2 (27:52):
And actually in some of these protocols, they make the
hot tubs really hot, like instead of your your hot
tubs supposed top out like hundred four degrees, but they
like juke the hot tubs up, so they go up
to one hundred and.
Speaker 3 (28:03):
Seven and then they're like leaving these people.
Speaker 2 (28:05):
It was like, it sounds horrible, but you do see
some performance impacts there, and in particular for people who
are going to like race in a hot environment and
now we're in like a really really niche area. But
if you're like training in someplace cold, but you're going
to race someplace hot, there's a lot of benefits to
heat acclamation, which you can do in a bunch of ways,
(28:25):
one of which is the hot tub. So you know,
this is like an I would say there's more evidence
for being hot than there is for being cold. But
we are still talking about very small Like if people
are listening to this and they're like, I'm a recreational
runner and I have like I'm you know, I'm trying
to like run a five k, Like, you don't need to,
(28:48):
the best use of your time is just to exercise
and have your regular life, not to get in the
hot tub. We're talking about, Like, if you are, you know,
a sub elite athlete and you're interested in adding something,
I'd add sauna instead of adding cold.
Speaker 1 (29:03):
Let's talk a bit about for us non athletes. I
have to represent my people. You mentioned that the FINS
put out a lot of sauna data, some of which
is fairly positive when it comes to things like mental
health and whatnot, which I always always get a little
suspicious when like all the data on something comes from
the country that's really invested in it. It's like if
(29:24):
the you know, if the Dutch put out like a
lot of positive clog studies or something, right, So we'll
take it with a grain of salt. Finland, But in
terms of subjective well being, it seems like these saunas
are good, right, I mean, it's a relaxing thing maybe
for some people.
Speaker 2 (29:42):
Yeah, I mean so, I think the most famous paper
on this is a paper about Finland which they looked
at long term mortality follow up for men in Finland
who spent different amounts of time in the sauna. And
you know, we'll talk a lot about studies like this,
but there are limitations to a study where you are
(30:02):
using what's called observational data, so people weren't randomized. There
may be different features between the people who spend seven
days a week in the sauna versus two days a
week in the sauna. But they find, you know, pretty
in that observational data there are quite large impacts on
cardiovascular mortality. And it's not inconsistent with some randomized data
(30:23):
about sort of cardiovascular improvements and other things like in
the heart space as a result of exposure to some
of these temperatures. So I think there's like there's sort
of a cardiovascular plausibility there. I mean, I'm curious if
that lines like. Another way to think about quality of
evidence here is to ask whether that effect which sort
of seems to be really a kind of cardiovascular effect
(30:46):
as opposed to something else, Like it really seems like
it's something about the cardiovascular system. Does that line up
with what you'd expect based on the physiology of this
of the heat.
Speaker 1 (30:57):
Yeah, yeah, I mean it seem like sauna in is
sort of a mild cardiovascular stressor it kicks your heart
rate up. It's almost like light exercise in terms of
blood pressure changes and heart rate changes. Emily, I see
you smiling because and you're right, it's not as good
as actually getting exercise, yes, but cardiovascularly there is some
(31:20):
of that. This introduces both an opportunity and a problem.
The opportunities. Yeah, okay, maybe it is good to get
your heart rate up a little bit. However you can
I suspect it's better to get it up by walking
around the block a few times than by sitting in
a sauna. But it's not nothing there. The other thing
is something we always worry about in epidemiological studies, which
(31:40):
is reverse causation where people who have some cardiovascular problems
might not be able to tolerate the sauna as much. And
so then when you kind of follow people over time,
you're like, oh, people who do more sauna live longer,
when in fact it's people who are less healthy do
less sauna to begin with, which sort of complicates the issue.
But I don't think it's inconceivable that either the cardiovascular
(32:00):
benefits or I'm a big believer in the power of
like doing something intentionally for yourself, And there's a lot
of stuff in this space where I think it's that
it's like, Okay, this is me time, right, Like I'm
getting in the sauna, I'm not bringing my phone. I'm
just sitting and with alone with my thoughts. And maybe
(32:21):
you don't even need the heat. Maybe it's just a
quasi meditative state that I think actually might be beneficial
for mental health.
Speaker 3 (32:27):
Do you think the same about the cold plunges or
is it?
Speaker 1 (32:30):
No? Not at all, No, because I think in the
cold plunge, I think instead of like quietly being with
your thoughts, your brain is like, what are you doing?
Please leave this horrible place. You're about to die. I'm
shutting down your body systems as we speak.
Speaker 3 (32:43):
Yeah, that's what I think.
Speaker 2 (32:45):
So one of the things people will sometimes talk about
is the idea that saunas are are a detox that
you're sweating out the toxins a lot of efforts to
get rid of toxin. So do you think that if
you sweat more you get more of.
Speaker 3 (32:58):
Your toxins out? And what are the toxins specifically?
Speaker 1 (33:01):
No, no, no, no, not a chance at all. You
have two organ systems that are designed to detoxify you,
the liver and the kidneys. That is their entire revolutionary purpose.
They do an amazing job. Sweat is ninety nine percent water.
The other one percent is salt sodium chloride. That's what
sweat is. So you will lose water, you will lose salt.
(33:24):
Both of these are things that nominally you need to survive,
and so we would want to replenish those after a sauna.
Just to put some numbers in it, there was a
study that looked at the excretion of organic pollutants in sweat.
So if we're worried about toxins, here's a good one
for you. Right. It's the stuff that like we spray
(33:44):
on crops and things like that. It's in our system,
it gets in our blood. You can measure these things.
And so took some people, put them in the sauna,
tested their sweat, and they determined that if you were
to leave people in the sauna for an entire day
and somehow they survey, so you know, getting a ton
of sweat out of these people, you would excrete through
(34:05):
the sweat zero point zero one percent of the daily
accumulation of organic toxins. So there is a measurable and
tiny amount, but it is spitting in the hurricane of
potential toxins that are out there to try to excretify
a sweat. That's not what sweat is designed for. That's
what urine is designed for. That's what bile is designed for.
(34:26):
You have organs that do this. Sweat is designed to
cool you off. It is extraordinarily good at this. If
humans are these amazing animals that evolved on the African
planes to do persistence hunts against animals that can't sweat
as efficiently as we can, and we maintain our cool
(34:47):
under the African sun and they collapse of heat stroke
and then we kill them like that is where we
come from. That is what sweats for not to get
your toxins out.
Speaker 2 (34:55):
Sorry, okay, but I think what people have noticed is
good story about the gazelles. But I think what people
have noticed is like, if you drink a lot at
night and then you go into a sna the next day,
you smell like a vodka and that I think people
perceive that.
Speaker 3 (35:12):
To be like, you know, cleansing them from toxins. So
is that why is that.
Speaker 1 (35:17):
Alcohol is special?
Speaker 3 (35:19):
Alcohol is special? I totally agree.
Speaker 1 (35:21):
Say more, alcohol and water do not know that they
are different chemicals from one another. So virtually throughout the body,
alcohol and water are freely exchanged in the solution of
your body. So whatever your blood alcohol content is is
your sweat alcohol content. It just they go together like that.
(35:44):
Now it's not much, but it is enough to potentially
be detectable. Again, it is not enough to clear alcohol
from your system by any stretch. You have an organ
that is designed to do this. It's called your liver.
Your liver can clear for an average man, and it varies,
but about a drink's worth of alcohol per hour from
(36:06):
your bloodstream. Don't try. This gets worse the more takes
you have sweating in a sauna, you know, we're talking
less than a hundredth of that amount. It's just not
the way to get alcoholic.
Speaker 3 (36:20):
It's not the hangover here that one hope for.
Speaker 1 (36:22):
No, it's definitely not, in fact, the dehydration that comes
from a sauna. It's probably gonna make things worse alsome thanks.
Speaker 2 (36:29):
Of course, the last thing I wanted to say on
the benefits is I came across what I think was
an extremely interesting study about women with obesity and PCOS
where they did it's a it's a relatively small set.
They did actually a pretty short intervention where they sort
of put them in the hot tub for an hour
(36:51):
a week for eight to ten weeks, and there actually
were a bunch of improvements in blood pressure and other
cholester all metrics, so no improvements in weight, but just
things that looked like, as you said at the beginning,
like a little bit like they had exercised, like similar
to if you had put people in exercise. So, you know,
(37:12):
I think part of what was interesting about that for
me was, you know, I think exercise is great, but
exercise is not always feasible for everybody and is not
something everybody wants to do. And so to the extent
that there's a this is sort of something that could
be helpful in some cases, maybe on the way to.
Speaker 3 (37:29):
Exercise, or maybe in addition to it.
Speaker 2 (37:32):
It feels like there's there's sort of something there that
might be meaningful enough that it's.
Speaker 3 (37:37):
Worth considering for some people. I buy it, okay, but
not all people.
Speaker 2 (37:41):
So what when we sort of talk about are there
people who should not do this pregnant?
Speaker 1 (37:48):
Yeah, yeah, there's always people who should not do everything.
You know. Again, if you're curious, if you're one of
these people, of course, talk to your doctor. But broadly speaking,
both of these hot and cold are mild cardiovass stressors.
So people with pre existing heart disease who are at
risk of heart disease, you know, certainly can be put
at mild risk by going into either of these situations.
(38:11):
People at risk of arrhythmias, particularly with the cold plunge,
and I'll just say it again, I would not put
your face in the water when you're in the cold plunge.
The problem with a rhythmias is that a lot of
people who at risk of them don't know that they're
at risk of them, at least the first time that happens.
And so does make me a little bit nervous. Obviously,
jumping into a cold body of water, as opposed to
(38:31):
like a tub in your backyard has extra dangers because
of that cold shock response. You know, people jumping into
cold lakes can just like go under and not come up,
and it's very hard to find them. Deaths have been described,
so you know this is something to take seriously and carefully.
I will also mention that there have been some studies
(38:52):
if you're a man that is interested in fertility, at
least in the short term, that prolonged exposure to heat
does kill sperm. And so if you know, if you're
you and your partner are trying to get pregnant, it's
probably not the best time to do significant sauna or
hot tubbing. And women who are pregnant that elevated body
(39:16):
temperature can certainly be damaging to the fetus, and so
we don't recommend hot, certainly for pregnant women, and I
probably wouldn't recommend cold in that case either.
Speaker 3 (39:27):
Just disagree.
Speaker 2 (39:29):
Actually, I spend a bunch of time at some point
looking at the cold plunge data in pregnancy, and I
would say, although you know, of course the data is
limited because cold plunging seems terrible and why would you
do it?
Speaker 3 (39:41):
Ever, there actually are.
Speaker 2 (39:44):
There is some evidence on this is actually no real
reason to think that, you know, particularly if you are
a person who generally does this, that you would need
to stop doing it when you were pregnant, which is
not the case of hot dubs and saunas, where the
risk for neeral tube defects, particularly for exposure in the
first trimester, means that that's a no, no.
Speaker 1 (40:03):
Fair enough, fair enough, all right, No, saunas may be
cold plunges, but be careful.
Speaker 2 (40:07):
So my last like risk question that I have always
wondered about is like, can you get frostbite from being
in the like if I get in and I have
some exposed parts fingers, toes for men.
Speaker 3 (40:22):
I mean, aren't you worried your penis is gonna get
frozen off? Honestly? Isn't that a thing I would be worried?
Speaker 1 (40:28):
Well, I hadn't thought about it until just now. Now
I'm worried. It's not my go to every time cheese.
So typically in frostbite, we imagine that it occurs when
the external temperature is below freezing because you have ice
crystal formation so that being said, you can get schemic digits.
(40:55):
So that response to cold is that the blood vessels
in your your superficial blood vessels constrict, and it can
be quite powerful. Particularly there's a phenomenon called Renod's phenomenon.
Many women have experienced this where and I mean men
have it too. It's just more common in women where
you have such severe vaso constriction in your finger typically fingers,
(41:17):
but it can happen in toes two that it's just white.
There's just no blood flow there that can be triggered
by cold plunges. And so many people who do this
routinely actually wear like some rubber gloves and rubber booties
and even rubber boxer shorts. To get to the issue
that you are referring to, Emily, to try to make
(41:38):
sure that those nibbly bits as we call them in
the medical profession don't get exposed to too much of
that cold. Broadly speaking, I think if you're healthy and
you don't have vascular problems to begin with, even some
vaso constriction from the cold plunge that is painful and
hurts is not going to result in the loss of
(41:59):
a digit the way you could if you were, you know,
outside in sub zero temperatures, so you.
Speaker 2 (42:03):
Won't lose your fingers, but your nibblelybits could be uncomfortable.
Speaker 3 (42:07):
Thank you.
Speaker 1 (42:08):
Yes, I'm sorry to use medical jargon.
Speaker 3 (42:11):
Well it's I think we're gonna be using that in
the future.
Speaker 2 (42:16):
Okay, So Perry, what is your one thing takeaway on
cold plunges and saunas for the listener.
Speaker 1 (42:25):
Cold plunges seems like modern day self flagellation. Be kind
to yourself. I don't think it's worth it. Saunas, sure,
go for it, primarily because it's a nice time to
have some time to yourself and relax, which we all
need more of.
Speaker 3 (42:39):
My one thing is similar.
Speaker 2 (42:41):
What I would say is if hot tub sauna on
a regular basis sounds like something that would serve you
emotionally or in some other way, then that seems lovely.
And in fact, if getting in this ic tub in
your backyard would serve the same things and that's a
nice date, that also seems fine.
Speaker 3 (43:02):
Up to the concerns.
Speaker 2 (43:04):
But for most people, I don't think I would invest
in either of these for significant health benefits. There are
a lot of other things I would put on the
list for people first.
Speaker 1 (43:15):
Sounds good. We will be back right after this with
your questions, and we're back with our listener question of
the Week.
Speaker 4 (43:29):
Hi, Emily and Perry. This is Ellie from Toronto, Ontario.
So I'm a parent in my late forties, and I've
been running on about five or six hours of sleep
at night for well many many years.
Speaker 3 (43:46):
So my question is I.
Speaker 4 (43:48):
Function, you know, I mean, I get through my day.
I've convinced myself that I've totally adapted to that amount
of sleep and it's fine.
Speaker 3 (43:56):
But I keep.
Speaker 4 (43:57):
Hearing that chronically not getting enough sleep can kind of
damage your health quietly, and so I'm wondering is regularly
getting this amount of sleep harmful if you feel fine? Like,
what does the research say about long term effects on
things like, you know, like my metabolism or my heart
(44:20):
or my mood, my weight, et cetera. And then I
guess the last pieces. If someone can't realistically get eight hours,
what are the most meaningful ways to reduce the damage.
Speaker 3 (44:33):
Thank you, Emiley.
Speaker 1 (44:35):
I'm so excited about this question because I get to
talk about familial natural short sleep, one of my favorite
and most awesome genetic conditions. So there are people out
there literally who do not need to sleep as much
as other people. Approximately one percent of the population have
this genetic condition called familial natural short sleep. I will
(44:58):
point out that it's not a syndrome or a disease
because it doesn't cause any problems. In fact, it seems
to be quite beneficial. These people need to sleep about
four to six hours a night, they suffer no ill effects.
They might even be protected against Alzheimer's disease. There's some
suggestion there it is inherited through families. But the fact is,
(45:18):
unfortunately that most of us aren't lucky enough to have
the special genetic mutation that prevents demension and makes you
not have to sleep at night.
Speaker 3 (45:26):
How would I know?
Speaker 2 (45:27):
So like before we get into regular people, how would
I know if I had this mutation?
Speaker 1 (45:31):
You might know because you sleep four to five hours
a night and feel completely fine, or at least you
might be. You might suspect. And then many of the
genes are actually known, so if you know, if you
were genotyped, they could detect that you had this variation.
Speaker 3 (45:44):
That is fascinating.
Speaker 2 (45:45):
However, most of us do not have this variation, and
most of us need more than this amount of sleep.
Speaker 3 (45:51):
That this person is getting.
Speaker 2 (45:52):
I mean, I so, first of all, I just think
we underestimate how important sleep is. I think most adults,
especially adults who have jobs and et cetera, kind of
think of sleep like a sort of nice to have,
you know, sort of like a pedicure, right, Like you know,
it'd be great if I could get one, my feet
would look better, but like if I can't get one,
it's totally fine. And I sort of think people should
(46:14):
think of sleep much more like a biological necessity, like
and if you don't get enough sleep, it's like torture.
I mean, sleep deprivation is a form of torture.
Speaker 3 (46:23):
And we know that.
Speaker 2 (46:25):
People's working memory and executive function is affected by even
relatively limited limitations on amount of sleep. So they have
these studies where they'll take away, you know, a couple
hours a night for some period of time, and over
a few days of that, you actually end up with
a level of functioning that's not dissimilar to if you
literally skip the night of sleep. And it's especially hard
(46:45):
on working memory, which is something that when you think
I need to do something and then you go into
the other room and you've forgotten what it is. That's
your working memory, and that's not good if you are
not sleeping enough.
Speaker 3 (46:58):
Yeah.
Speaker 1 (46:58):
I couldn't agree more. It's super important. Most people need
about six and a half to eight and a half
hours a night. People do very a little bit around there,
but you really got to get it in there. You've
got to prioritize it the same as you think about
like getting some exercise or eating well or whatever. It
is a critical thing to focus on, so do your best.
Speaker 2 (47:14):
I will also say, you know, I want to recognize
that it is really hard to get enough sleep and
that for a lot of people listening to this, you
probably have multiple jobs and multiple children. And so this
is partly you know, giving yourself a break and saying like, hey,
if I'm not in bed you know at ten o'clock
fully asleep and up at you know six, like Brian Johnson,
(47:35):
like it's okay, Like you're not going to immediately die.
But it's also saying, you know, this should be something
you prioritize, and so thinking about, you know, what is
feasible for me to improve my sleep. I think that's
something that we should care about. And I think at
some point we should do a whole episode on the
science of sleep, because I love the science of sleep.
Speaker 3 (47:54):
Every animal sleeps, It's so interesting.
Speaker 2 (47:56):
Dolphins sleep, has their brains at a time while they're swimming.
Speaker 3 (48:00):
I'm going to pull out so many great facts for you.
Speaker 2 (48:02):
So, Perry, do you have any quick tips for better
sleep if someone wants more sleep?
Speaker 1 (48:07):
The standard sleep hygiene stuff here, which is, you don't
want to drink caffeinated beverages typically after like four pm.
You might not even want to drink any beverages as
you approach eight o'clock nine o'clock at night, just so
you don't have to wake up in the middle of
the night to pee. We want people sleeping in dark,
quiet rooms as much as possible. Those noise machines and
stuff can actually disturb sleep a little bit if you
(48:28):
are an allowed environment. Ear plugs are awesome if they're
comfortable for you, and the bed is a place to
sleep and have sex, not to eat and watch TV
and be on your phone and whatnot. I'm okay with
reading in bed, but I would read an actual book
as opposed to a phone, because that blue light that
comes from the screen can actually keep you up a
(48:48):
little bit.
Speaker 3 (48:49):
That's it.
Speaker 1 (48:53):
Join us next week when we ask what's the deal
with the blockbuster weight loss drugs GLP ones.
Speaker 2 (49:00):
Wellness Actually is produced in association with iHeartMedia.
Speaker 3 (49:03):
Our senior producer is Tamar Avishai.
Speaker 2 (49:06):
Our executive producer at iHeart is Jennifer Bassett. Our theme
music is by Eric Deutsch, and our content is for
educational purposes only.
Speaker 1 (49:14):
If you like the show, help other people find us.
Leave a rating and review on Apple Podcasts or your
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the show. Don't give the TikTokers all the power, and
don't forget we want to hear from you. Head over
to Wellness Actually dot fm and leave us a question
for our mailbag or suggest a topic for a future show.
Speaker 3 (49:34):
We'll let the influencers have the last word, all.
Speaker 5 (49:36):
Right, guys. So I am three weeks into cold Plunging,
and I'm going to explain to you, guys the differences
I'm noticing and whether I think this is worth it
or not for you guys to go out and get
a cold plunge for yourself.
Speaker 1 (49:46):
Or build one.
Speaker 5 (49:47):
But I've been doing it for three weeks now, every
single morning, and I will tell you the very first
thing is that I highly underestimated how much I was
not going to want to get into that cold plunge
every day
Emily, I have an audio challenge for you. Are you ready,
I'm ready, Okay. I want you to listen to this
following clip, and your job is just to tell me
what's going on here. I don't know if I could
do this. However, it is a countdown.
Speaker 2 (00:25):
Countdown, So Perry, I think this is going to reveal
too much about my Internet consumption. But I think that
I have seen the video associated with that audio on
TikTok wow, and that person is cold plunging in an
icy lake.
Speaker 1 (00:46):
I believe I have once again underestimated your ability to
understand the Internet zeitgeist. Emily. You're correct, that is not
a lake. It is a tub of some kind that
is filled with icy water. But I will say that,
being new to exploring the world of social media wellness
influencers and looking at a bunch of cold plunge of videos,
(01:09):
this is what I took home was this seems terrible.
No one enjoys this.
Speaker 3 (01:18):
I agree.
Speaker 2 (01:19):
I think that if there are any benefits, it is
that you are just so happy to be out and
not dead that everything about your life after that seems
better because you are not in an ice pit.
Speaker 1 (01:31):
There's no joy without sadness. Perhaps that is the philosophy
of cold plunges. This week, we're going to explore extreme
cold temperatures on your body as well as hot temperatures
on your body in the form of Sauna's two ends
of a bipolar system of stressing the body with temperature.
We'll figure out if the data supports whether these things
are beneficial or not. Should we dive in?
Speaker 3 (01:52):
We should dive in.
Speaker 2 (01:56):
I'm Emily Oster, I'm an economist and a data expert.
Speaker 1 (02:00):
I'm Harry Wilson, I'm a medical doctor.
Speaker 2 (02:02):
It's Thursday, February twenty sixth twenty twenty six, and this
is wellness actually.
Speaker 1 (02:07):
Because you're getting a staggering amount of health and wellness
information nowadays from every source imaginable, and some of it
is awesome and.
Speaker 2 (02:16):
Some of it is well actually both. Fortunately we are
both people who know how to read studies, how to
parse the data, and can tell you what's worth thinking about.
Speaker 3 (02:27):
And what you can safely ignore.
Speaker 1 (02:29):
But before we dig in, a note that this podcast
is for educational purposes and should not be construed as
medical advice. We don't know your unique situation, so talk
to your doctor for personal health decisions.
Speaker 2 (02:40):
This week, we're asking what's the deal with cold plunges
and saunas? And then we'll get to your question of
the week, But first let's do the health news roundup
after the break.
Speaker 1 (03:01):
Now onto the health news of the week, Emily, I'm
looking at CDC dot gov measles numbers through last week.
Through February thirteenth, there have been nine hundred and ten
total cases to date this year twenty twenty six in
the United States. There were twenty two hundred and eighty
in all of twenty twenty five last year. If you
(03:24):
do the math, we're at about three times higher than
twenty twenty five, which was a particularly bad year to
begin with their measles outbreaks in the majority of states.
What are you taking home from the new data?
Speaker 2 (03:40):
The measles data is really pretty scary.
Speaker 3 (03:44):
I mean, I think it's worth saying.
Speaker 2 (03:47):
You highlighted that we are saying more cases than twenty
twenty five. Let me give you a what I think
is a sharper fact, which is that in a single
week in January of this year, we had more measles
cases than all but a small hand full of years
over the past three decades. And so really this is
an unprecedented set of outbreaks.
Speaker 3 (04:08):
We are likely to continue seeing them.
Speaker 2 (04:09):
So those numbers that you gave go through the sort
of second week of February already. Since those there have
been announcements of a reasonably large outbreak at a college
in Florida, announcements of the beginnings of an outbreak in
Salt Lake City. So we're going to start seeing more
of this around. And it is happening for a very
basic reason, which is that measles is super contagious. It
(04:33):
can live for a very long time on surfaces. So
one number is probably useful to put out there is
when we talk about diseases in their contagiousness, we talk
about a number called are not which is like how
many people someone is expected to infect if we kind
of had a totally disease naive population. And so for measles,
that numbers estimated to be sort of somewhere in the
(04:54):
range of like twelve to eighteen. So every case of
measles infects another twelve to eighteen p Well, by contrast,
for a number like flu, it's a little bit above one,
maybe maybe sort of one to two. And so this
is just so contagious and when it faces a population
with lower vaccination rates, which is what we have, a
lot of people are going to get measles, and that's
(05:15):
just kind of what's going to happen.
Speaker 3 (05:17):
That's it.
Speaker 1 (05:18):
Yeah, there's really no reason to get measles. That's that's
the thing that I keep coming back to. I see
these stories of kids who've been hospitalized. A couple of
children died last year. You know, you can read the
statements from families by and large, who even in the
face of this, will often say things like, you know,
I don't regret the choices I made, and I understand
(05:39):
there's some self defense mechanisms at play here, but just
to say it out loud, like measles is one of
those things that we have defeated by and large, like
we won this particular battle. There's no reason to keep
fighting it.
Speaker 2 (05:51):
Yeah, I mean, I think it's just it's just very
sad to say, you know, children will die this year measles.
Measles mortality rates something like one in a thousand, so
there will be kids this year.
Speaker 3 (06:01):
Who will die of measles who could have not died.
Speaker 2 (06:05):
And I think when you put it like that, it's
just that's just really sad.
Speaker 3 (06:09):
That's all. Yeah, it's really sad. Okay.
Speaker 2 (06:13):
Moving on to some appointment news in the federal government.
So j Badicharia, former professor at Stanford, economist and doctor.
Speaker 3 (06:24):
So he's like both of.
Speaker 1 (06:25):
Us, the perfect mix of you and I.
Speaker 2 (06:29):
I'm sure he is in charge of the NIH and
has now been named as the acting director of the CDC.
Jay is known for many things, but one of them
is during COVID, he was one of the authors of
the Great Barrington Declaration, which in the fall of twenty
twenty argued for a more focused approach to COVID, which
would have protected the elderly but allowed COVID to spread
(06:51):
more widely among healthy people. You got a lot of
attention and hate for this at the time. He has
now been put in charge of not one, but two
major parts of the federal disease infrastructure.
Speaker 1 (07:02):
Your thoughts, including the part of the federal disease infrastructure
that's responsible for containing outbreaks of disease, just to say it. So,
let me take issue with one thing you said about
the Great Bearrington Declaration, which, as you said, it would
have protected older people and let the virus sort of
spread throughout you know less vulnerable populations. That was the pitch.
(07:23):
I think the reality is protecting older people. You can't
just say like, oh, we will protect people. You have
to actually demonstrate it, and as all outbreaks have shown us,
it's really hard to do that, Like do you try
to isolate people? Are you sliding food under the doors
of older people's homes and so on and so forth.
So you know, I don't think the Great Bearrington Declaration
(07:44):
was well thought out. It was primarily ideological, and that
seems to be the way this administration works is that
they pick an ideology that they favor, and they put
people in charge of the scientific apparatuses who believe in
that ideology as opposed to people that are behaving like scientists,
which is to look at data and to derive conclusions
(08:07):
from the observable data.
Speaker 2 (08:09):
Let me say one thing here where so I know
Jay pretty well, and he is a very smart guy
who you know, getting back to our measles discussion, I
think does fundamentally believe in routine childhood vaccinations, and if
you asked him, would say people should get the measles vaccine.
(08:29):
So I have what is presumably a somewhat naive hope,
but I do think that relative to some of the
vaccine rhetoric that we're seeing coming out of the administration,
this is a more evidence based voice on some of
these pieces. I'm a little worried that the job of
being both in charge of the NIH and in charge
(08:50):
of the CDC is just too much job for a
single person, even an economist.
Speaker 3 (08:54):
It is.
Speaker 1 (08:55):
It is a big job. I hope you're right. I'm
not going to hold my breath. I think what I've
seen from even very smart people in this administration, and
I know some of them too, although I don't know
Jay is a tendency to cave to the political wins
as opposed to the scientific evidence. But we'll see.
Speaker 3 (09:13):
I guess we'll find out.
Speaker 1 (09:15):
Speaking of terrible pandemics that may imminently sweep the nation,
I'm wondering if you saw this article about a five
thousand year old bacteria that was discovered in an ice
cave in Romania that just so happens to be resistant
to like all modern antibiotics. So, like I've read this book,
(09:37):
I'm pretty sure I think we all turned into zombies
in the next sixteen to ninety days.
Speaker 3 (09:41):
Big Michael Crichton wrote like nine versions of this book.
Speaker 1 (09:45):
Yeah, yeah, all great.
Speaker 2 (09:46):
This is published in a Frontiers journal. So the discussion says,
this bacteria SC sixty five a dot three sounds like
a peptide, represents an ancient ice adapted psychic bactor with
a dual profile of multi drug resistance and antimicrobial activity,
highlighting ice caves as under explored reservoirs of ancient resistomes
(10:09):
and bioactive traits.
Speaker 3 (10:10):
I felt like when I read that, I was like, man,
let's maybe not.
Speaker 2 (10:13):
Explore more, maybe over explored more or less leave the
ice caves where they are. So is I mean, realistically,
should we be concerned about ancient bacterias coming out of
the explored ice caves.
Speaker 1 (10:27):
I think there's a theoretical concern. The authors actually in
that paper they're quite positive. They're like, oh, we can
learn new ways that bacteria develop antibiotic resistance that we
hadn't thought of, and thus we can create new antibiotics.
So there's always there's always value here. You do have
to be careful. I mean, the truth is that there's
permafrost all over the Earth that contains ancient organisms, some
(10:50):
of which are capable of infecting humans, and some of
which haven't infected humans for thousands of years, but nevertheless
can persist under the ice, and some of that ice
receding right as the as the climate warms, and so,
you know, there are a lot of ways that new
pathogens can get into the human population. The most common
is we, you know, invade the territory of some animal
(11:11):
that we haven't had a lot of interaction with, and
some virus in that animal or vectory, and that animal
hops into humans. That's, you know, probably what happened with
All the Stars viruses like COVID and any number of others,
as well as several Michael Crichton books. But you know,
ice ice melting is another potential vector here. It's definitely
something that we should be aware of, but probably not
(11:32):
freak out about.
Speaker 3 (11:33):
Okay, I think that's it for the health news.
Speaker 2 (11:35):
I feel like next week we need to go have
more Olympics because I miss the discussion of condoms.
Speaker 3 (11:40):
I would rather discuss Olympic condoms.
Speaker 1 (11:42):
We could discuss. We should kind of have a running
like how many condoms have they used now? And let's
just have that number exponentially rising, I assume as we
get closer to the end.
Speaker 2 (11:51):
So with that first a break and when we come back,
cold plunges and saunaus.
Speaker 1 (12:02):
All right, we are back, and it's time to talk
about your hot and your cold. You know, Katie Perry
is on my mind this week because we're talking about
cold plunges and saunas. Both of these things are all
over the wellness space. You've got promoters on all sides.
As I've explored this, I've seen people making claims from
(12:26):
the idea that they're a nice way to relax after
a workout, to they will improve diabetes control. I mean,
it is all over the map. Lots to dig into here,
but Emily, before we get started, I feel like we
need to just kind of define our terms. Can you
walk us through, like what is a cold plunge? What
is a sauna? All right?
Speaker 2 (12:46):
So generally, and I will say, part of what's hard
about this space is that this is not well defined
because really we're talking about a lot of things, many
of which are done in the wellness space, which is
an unregulated vague.
Speaker 3 (13:00):
But when people talk about.
Speaker 2 (13:01):
Cold plunges, they are generally referring to being in a
some body of water largely submerged for an amount of
time that varies from like I jumped in the water
and I got immediately out to sitting for you know,
five or ten minutes. The water is generally extremely cold,
(13:24):
typically ice icy. Often people will do this and the
like low budget version of this. This guy, I've got
like a giant backyard like metal tank, and then my
Instagram video will have me walking out and like cutting
a hole in the ice on the top of my
tank and then getting into it, often with my husband
or wife, so we can have a romantic popsicle.
Speaker 1 (13:47):
Worst date night ever, worst date ever.
Speaker 3 (13:50):
But anyway, so that's so it's very very cold. Of
course they also make like.
Speaker 2 (13:54):
More expensive tubs that will regulate this temperature for you.
But it's very cold relatively short period of time. Then
there's a sort of hot side of this, which actually
is quite a bit more varied. So you can be
hot in a sauna, or you can be hot in
a hot tub, or actually in sports, you can be
hot in like exercising in like a winter coat.
Speaker 1 (14:16):
Oh yeah, and like hot yoga. Right, I mean, I
guess that's a sauna, right.
Speaker 2 (14:21):
Sua, although it's not like a dry son it and
in fact, if you get.
Speaker 3 (14:25):
Into like the Fins.
Speaker 2 (14:26):
A lot of the data on saunas from people in Finland,
and the Fins have like a lot of really specific
things about their saunas, like different kinds of saunas.
Speaker 3 (14:34):
The saunas are the rocks, the saunas without the rocks,
I don't know.
Speaker 2 (14:37):
At any rate, you are quite hot for a period
of time, and typically a bit longer. So sauna or
hot tub exposure is often something like a half an hour,
you know, longer in the hot tub than than in
the sauna, And the idea is just to raise your
to raise your body temperature for.
Speaker 3 (14:53):
Some extended period of time.
Speaker 2 (14:55):
So basically we're talking about being either very cold or
very hot. I think it's just worth saying both of
these are uncomfortable. So we're talking about not like a
relaxing bath with candles. We're talking about like most people
do not enjoy being in a hot tub for thirty minutes,
especially since in the heat treatments usually you have to
(15:16):
have your arms in, so you're just really hot.
Speaker 3 (15:19):
Like it's just like really hot and uncomfortable, or really
cold and uncomfortable.
Speaker 1 (15:24):
But but if I had a nice finished sauna in
my office right here, and a giant bathtub full of ice.
You ask me which one I'd rather spend fifteen minutes,
and I'm taking the sauna every day of the week.
Speaker 2 (15:37):
Just going to say it, I think that's right. I
hate being both hot and cold. I just I like
to be one intermediate temperature that's perfect. I find both
of these ideas like almost unbearable.
Speaker 3 (15:49):
But I do think I would also.
Speaker 2 (15:50):
Choose hot, although last time I was in a sauna,
I literally made it forty five seconds before I was like,
oh my god, I have to leave.
Speaker 3 (15:57):
I'm going to die.
Speaker 1 (15:58):
Okay, Oh you're okay. So you're really like your your
homeothermia or whatever, meaning yeah, sure, regular persones somewhere somewhere
in the middle. But if there are real health benefits, right, like,
maybe it's worth it. Maybe what I think we need
to figure out.
Speaker 2 (16:12):
All right, let's before we figure out the health benefits, though,
let's talk a little bit about like why these might matter.
Like what's the physiology, So you're the doctor, what is
the physiology of these kinds of exposures to extreme temperatures?
Speaker 1 (16:26):
Sure, and let me say like a little bit of
philosophy of wellness here where I think this might be
a recurring theme in our podcast, which is that in
medical science we start with this concept called biologic plausibility,
which is is it possible that this thing works? Not
does it work? Just like does it make sense? You know,
(16:47):
if someone came and said eating red jelly beans cures cancer,
I would say there's no biologically plausible way that that
is true. It's not really worth your time. Where I
think wellness gets it wrong is that they stop there
say like, oh, it's plausible and therefore it does. And
where we need to go is like, Okay, maybe it's plausible,
but like does it actually And there's there's a wider
(17:09):
gap between plausible and reality than people often think. So
let's first of all, just talk about biologic plausibility. The
physiology of cold water plunges is pretty interesting and we
have a good amount of data on this, believe it
or not, because the military is really interested in what
happens to people when they drop into cold water. This
(17:30):
is something I guess that we do. We probably do
it more often than we know that we do. And
so the Department of Defense has funded quite a few
studies exploring like the short term and medium terms effects
of these cold water plunges. It's not exactly the same
as you know, calmly getting into ice water in your backyard.
But there's a very standard physiologic response called the cold
(17:52):
shock response, which is well described, which happens in the
first thirty to ninety seconds of getting submerged in cold
water at about forty degrees already five degrees or less,
and it is essentially involuntary. It is characterized by a
deep and rapid intake of breath, like a feeling yeah,
(18:12):
and that's about three liters of air intake. And just
to put it in context, breathing kind of normal like
in and out is you know, maybe a leader in
and out of air intakes, so you're really this very
deep breath and this is actually when people fall through
the ice or something. This response is what results in
a lot of drowning because if your head's underwater and
you do that, you just suck in a ton of water,
(18:34):
it can be very dangerous. You get this dramatic again
first thirty ninety seconds, a dramatic increase in the sympathetic
nervous system. This is that fight or flight response, which
is going to increase your heart rate, your blood pressure spike,
your cortisol levels. It increases adrenaline levels by a factor
of about five. In these studies, your adrenaline just goes
(18:55):
through the roof in those sixty minutes. Interestingly, dopamine level
increase bye two and a half fold. So we often
think of dopamine as sort of like a feel good chemical.
But you've got a lot of a lot of chemistry
going on in that first minute in the ice, and
it's obviously not entirely pleasant.
Speaker 3 (19:14):
What was the pleasant part the dopamine? Oh, the dope
mean the don't mean that's going up? But is the
dopaine going up? So your body is convinced, like, don't
just die right now? Things could improve the next ninety six.
Speaker 1 (19:27):
Yes, we call it hopamine. It's like, uh, I'll give
you a hug and then slap you in the face
as hard as I can. I don't know, it's not great.
I just want to give the good in the bad. Okay.
Vaso constriction So when you get cold, your superficial blood
vessels constrict to reduce heat loss to the environment, so
blood gets shunted away from your skin and potentially your muscles.
(19:48):
I think we need to get into this a little
bit to your central organs, which are the things that
really need to keep you alive, so like your heart
and your brain and your kidneys. To some extent, it
also makes you have to pee, and as a kidney doctor,
we see this non frequently in the hospital. So after
someone has a traumatic brain injury or a stroke, if
we catch them in time and they're in very severe cases,
(20:09):
we will induce hypothermia. There is some data there for
brain injuries that recovery is better with hypothermia, and we
do see that as you reduce their body temperature of
the year, an output goes up because blood is getting
shunted away from the periphery and into the kidneys. So
if you jump in that cold plunge pool and then
you have to get right out to pee, that's a
great excuse. One last thing on physiology, because this is
(20:33):
something that's actually potentially dangerous with cold plunges, and that
is the mammalian diving reflex. This is a thing that
happens when you submerge your face in cold water. It
basically is an evolutionary artifact of our instinct to change
our physiology when we're swimming, or especially when we're going
(20:54):
deep underwater. What happens in the mammalian diving reflex again
only if you put your face in the water, is
your heart rate goes down. It sort of slows your metabolism.
And this is potentially a problem because the cold shock
response makes your heart rate go up, the mammalian diving
reflex makes your heart rate go down, and there is
some evidence that those conflicting signals can precipitate a cardiac arrhythmia,
(21:20):
and people have died within the first couple of minutes
of a cold plunge potentially through this mechanism.
Speaker 3 (21:26):
So don't put your face in the water.
Speaker 1 (21:27):
Don't put your face in the water. Like I saw
on a lot of the tiktoks, is like okay, you're in,
like now, go all the way and like probably not
actually certainly not in the first couple of minutes while
you still have the cold shock response going on. So
that is the cold side of things.
Speaker 3 (21:43):
Okay, it sounds terrible. Tell me about being hot.
Speaker 1 (21:47):
Okay, the warm side I think is a little bit better.
So what happens when you're exposed to heat is that
your body does stuff to reduce your body temperature. And
the thing it does is it dilates blad vessels in
your skin so that more blood gets to the skin
the surface areas, you can exchange heat better with your environment,
and then you do this amazing thing that humans are
(22:08):
very proficient at, which is that you sweat. And so
one of the reasons those finish saunas can get to
such a higher temperature than the steamy saunas is because
you have evaporation of sweat, which is cooling you off,
whereas if you're in steam, your sweat won't evaporate, So
people can tolerate the finish saunas quite a bit better.
(22:30):
Because of sweating, you can lose a lot of water
through sweat, though you can put out leaders of water
in a hot enough sauna you spend enough time there,
so dehydration is certainly something to think about. There have
been some studies that show that that warmth does release
some endorphins, which are sort of you know, endogenous feel
good chemicals. So taken all together, it's not as like,
(22:54):
oh my god, I'm about to die as a cold plunge,
but still might not be pleasant for you. Emily. All right, okay,
so now we know what happens, right.
Speaker 3 (23:04):
Question is whether it's important.
Speaker 1 (23:06):
Whether it's helpful biologic plausibility wise, there's something here. It
does something right. Maybe increasing your part rate is good.
It's like a little exercise, you know, vasodilation, phasoconstriction. You
could make arguments that these are good things, but we
really need to figure out like, okay, are they good things?
And I think where ice has got its most data
(23:28):
emily is for athletes, right, like particularly like athletes who
are really doing endurance stuff. Can you tell me about that?
Speaker 3 (23:36):
Yeah?
Speaker 2 (23:37):
So I think both ice and heat are things that
people who are doing like serious sports try to experiment with.
Speaker 3 (23:43):
And I think we sort of start with ice.
Speaker 2 (23:45):
The idea again to get to the biological plausibility issues.
The idea behind ice is sort of similar to, like
I have an injury I have which partly is inflammation.
You ice your injury. That's like a well known approach
to prevention. I think there's a kind of extension into
the sort of cold plunges in icing, which is like,
well maybe if I just iced my whole body, that
(24:08):
would like lower my inflammation overall, and it might improve
recovery and ideally improved performance. I mean, I think part
of what's I guess is we'll talk about this a
lot of them podcasts, But there's actually a lot more
research on a lot of these topics in athletes than
there is in other people, in part because it's a
very easy population to study, because you know what you're.
Speaker 3 (24:27):
Trying to achieve and it's short term.
Speaker 2 (24:29):
Right, So you can say, Okay, I'm going to put
people in this protocol, dump them in the ice after
their you know, cycling test, you know, every day for
three weeks, and then I'll do it not for three weeks,
and I'll measure their VO two max on a special bike.
Speaker 3 (24:41):
And blah blah blah.
Speaker 2 (24:42):
And it's like just much easier to think about what
you're trying to accomplish and how to measure it.
Speaker 3 (24:46):
Yeah, and so many of.
Speaker 2 (24:47):
The problems we have studying regular people is what we're
trying to say is like do you live to be
one hundred? And like I can't measure that three weeks
from now, obviously exactly, So I will say when we
look at ice, my sense of the literal sure is
that it's really not that great that these cold plunges.
Maybe they have you know, a little bit of an
(25:08):
impact on sort of subjective muscle soreness. But in terms
of recovery and performance and so on, there just isn't
much consistent evidence that these things matter.
Speaker 1 (25:19):
A lot of the studies have this.
Speaker 2 (25:21):
Feature that it's like, well, we did this and we
looked at these you know, forty seven different outcomes and
you know, three of them it mattered, and it's like, yeah,
but that's actually not a very statistically robust result. So
I for me, the like ice for athletes is a
bit of a dud.
Speaker 1 (25:38):
Yeah, I you know, as I was looking into this,
I sort of assumed that at least for the real
you know, real athletes, right, like the professional athletes, because
you see these like the football players and the baseball
players with the professional trainers and everything like, and they
have these ice bats in the training house. And I
saw enough videos of professional athletes like talking about the
(26:00):
process before they get into the ice bath, like what
they have to go through mentally and physically. You know,
they're like, okay, I've got it because they hate it, right,
Like they've got a mentally prepare Like some of them
are drinking really hot tea. They're putting on like rubber
gloves and boots and things like that. So that they
don't get like a schemia of their digits and things.
(26:20):
And then they you know, they get in and it
has this feeling like, well, it must be really beneficial
because they're they're putting themselves into this and and you're right,
you know. Looking at the data, I couldn't find much.
I found one study that looked at the level of
a substance called creatine kinase, which is a muscle enzyme.
(26:41):
It goes up when you work out really vigorously because
you do damage muscles when you work out hard. In fact,
that's the way your muscles get bigger, is that you
sort of damage them and then they get they come
back stronger, and so CK levels go up after exercise,
and the people that they randomize to do the ice
bath it didn't peak quite as much. But I'm not
(27:01):
sure that means that, like that's even better for you, right, Like, yeah,
don't you kind of want some muscle damage? I mean
that's right, Like if you're trying to build muscle, I.
Speaker 2 (27:09):
Mean, yes, you do need to damage your muscles to
try to build them. But I think the more generally,
like where's the where's the performance out come?
Speaker 1 (27:15):
There?
Speaker 2 (27:15):
You know, this is like we're measuring all of these
things and like we don't really we don't have a
great sense of that that translates into performance. And I
think if you look at this sort of true performance stuff,
being cold is just we just don't have like a
lot of good evidence.
Speaker 1 (27:29):
All right, professional athletes take notes.
Speaker 2 (27:31):
On the other hand, I will say I think the
evidence on heat in sports is somewhat more compelling.
Speaker 3 (27:38):
The typical protocol.
Speaker 2 (27:40):
Here is hot tub, so basically taking people in after
their workout, putting them in a hot tub for thirty minutes.
Speaker 1 (27:46):
This is literally the opposite of what we just talked about.
So I feel like both of these can't work.
Speaker 3 (27:51):
People don't like this either.
Speaker 2 (27:52):
And actually in some of these protocols, they make the
hot tubs really hot, like instead of your your hot
tubs supposed top out like hundred four degrees, but they
like juke the hot tubs up, so they go up
to one hundred and.
Speaker 3 (28:03):
Seven and then they're like leaving these people.
Speaker 2 (28:05):
It was like, it sounds horrible, but you do see
some performance impacts there, and in particular for people who
are going to like race in a hot environment and
now we're in like a really really niche area. But
if you're like training in someplace cold, but you're going
to race someplace hot, there's a lot of benefits to
heat acclamation, which you can do in a bunch of ways,
(28:25):
one of which is the hot tub. So you know,
this is like an I would say there's more evidence
for being hot than there is for being cold. But
we are still talking about very small Like if people
are listening to this and they're like, I'm a recreational
runner and I have like I'm you know, I'm trying
to like run a five k, Like, you don't need to,
(28:48):
the best use of your time is just to exercise
and have your regular life, not to get in the
hot tub. We're talking about, Like, if you are, you know,
a sub elite athlete and you're interested in adding something,
I'd add sauna instead of adding cold.
Speaker 1 (29:03):
Let's talk a bit about for us non athletes. I
have to represent my people. You mentioned that the FINS
put out a lot of sauna data, some of which
is fairly positive when it comes to things like mental
health and whatnot, which I always always get a little
suspicious when like all the data on something comes from
the country that's really invested in it. It's like if
(29:24):
the you know, if the Dutch put out like a
lot of positive clog studies or something, right, So we'll
take it with a grain of salt. Finland, But in
terms of subjective well being, it seems like these saunas
are good, right, I mean, it's a relaxing thing maybe
for some people.
Speaker 2 (29:42):
Yeah, I mean so, I think the most famous paper
on this is a paper about Finland which they looked
at long term mortality follow up for men in Finland
who spent different amounts of time in the sauna. And
you know, we'll talk a lot about studies like this,
but there are limitations to a study where you are
(30:02):
using what's called observational data, so people weren't randomized. There
may be different features between the people who spend seven
days a week in the sauna versus two days a
week in the sauna. But they find, you know, pretty
in that observational data there are quite large impacts on
cardiovascular mortality. And it's not inconsistent with some randomized data
(30:23):
about sort of cardiovascular improvements and other things like in
the heart space as a result of exposure to some
of these temperatures. So I think there's like there's sort
of a cardiovascular plausibility there. I mean, I'm curious if
that lines like. Another way to think about quality of
evidence here is to ask whether that effect which sort
of seems to be really a kind of cardiovascular effect
(30:46):
as opposed to something else, Like it really seems like
it's something about the cardiovascular system. Does that line up
with what you'd expect based on the physiology of this
of the heat.
Speaker 1 (30:57):
Yeah, yeah, I mean it seem like sauna in is
sort of a mild cardiovascular stressor it kicks your heart
rate up. It's almost like light exercise in terms of
blood pressure changes and heart rate changes. Emily, I see
you smiling because and you're right, it's not as good
as actually getting exercise, yes, but cardiovascularly there is some
(31:20):
of that. This introduces both an opportunity and a problem.
The opportunities. Yeah, okay, maybe it is good to get
your heart rate up a little bit. However you can
I suspect it's better to get it up by walking
around the block a few times than by sitting in
a sauna. But it's not nothing there. The other thing
is something we always worry about in epidemiological studies, which
(31:40):
is reverse causation where people who have some cardiovascular problems
might not be able to tolerate the sauna as much. And
so then when you kind of follow people over time,
you're like, oh, people who do more sauna live longer,
when in fact it's people who are less healthy do
less sauna to begin with, which sort of complicates the issue.
But I don't think it's inconceivable that either the cardiovascular
(32:00):
benefits or I'm a big believer in the power of
like doing something intentionally for yourself, And there's a lot
of stuff in this space where I think it's that
it's like, Okay, this is me time, right, Like I'm
getting in the sauna, I'm not bringing my phone. I'm
just sitting and with alone with my thoughts. And maybe
(32:21):
you don't even need the heat. Maybe it's just a
quasi meditative state that I think actually might be beneficial
for mental health.
Speaker 3 (32:27):
Do you think the same about the cold plunges or
is it?
Speaker 1 (32:30):
No? Not at all, No, because I think in the
cold plunge, I think instead of like quietly being with
your thoughts, your brain is like, what are you doing?
Please leave this horrible place. You're about to die. I'm
shutting down your body systems as we speak.
Speaker 3 (32:43):
Yeah, that's what I think.
Speaker 2 (32:45):
So one of the things people will sometimes talk about
is the idea that saunas are are a detox that
you're sweating out the toxins a lot of efforts to
get rid of toxin. So do you think that if
you sweat more you get more of.
Speaker 3 (32:58):
Your toxins out? And what are the toxins specifically?
Speaker 1 (33:01):
No, no, no, no, not a chance at all. You
have two organ systems that are designed to detoxify you,
the liver and the kidneys. That is their entire revolutionary purpose.
They do an amazing job. Sweat is ninety nine percent water.
The other one percent is salt sodium chloride. That's what
sweat is. So you will lose water, you will lose salt.
(33:24):
Both of these are things that nominally you need to survive,
and so we would want to replenish those after a sauna.
Just to put some numbers in it, there was a
study that looked at the excretion of organic pollutants in sweat.
So if we're worried about toxins, here's a good one
for you. Right. It's the stuff that like we spray
(33:44):
on crops and things like that. It's in our system,
it gets in our blood. You can measure these things.
And so took some people, put them in the sauna,
tested their sweat, and they determined that if you were
to leave people in the sauna for an entire day
and somehow they survey, so you know, getting a ton
of sweat out of these people, you would excrete through
(34:05):
the sweat zero point zero one percent of the daily
accumulation of organic toxins. So there is a measurable and
tiny amount, but it is spitting in the hurricane of
potential toxins that are out there to try to excretify
a sweat. That's not what sweat is designed for. That's
what urine is designed for. That's what bile is designed for.
(34:26):
You have organs that do this. Sweat is designed to
cool you off. It is extraordinarily good at this. If
humans are these amazing animals that evolved on the African
planes to do persistence hunts against animals that can't sweat
as efficiently as we can, and we maintain our cool
(34:47):
under the African sun and they collapse of heat stroke
and then we kill them like that is where we
come from. That is what sweats for not to get
your toxins out.
Speaker 2 (34:55):
Sorry, okay, but I think what people have noticed is
good story about the gazelles. But I think what people
have noticed is like, if you drink a lot at
night and then you go into a sna the next day,
you smell like a vodka and that I think people
perceive that.
Speaker 3 (35:12):
To be like, you know, cleansing them from toxins. So
is that why is that.
Speaker 1 (35:17):
Alcohol is special?
Speaker 3 (35:19):
Alcohol is special? I totally agree.
Speaker 1 (35:21):
Say more, alcohol and water do not know that they
are different chemicals from one another. So virtually throughout the body,
alcohol and water are freely exchanged in the solution of
your body. So whatever your blood alcohol content is is
your sweat alcohol content. It just they go together like that.
(35:44):
Now it's not much, but it is enough to potentially
be detectable. Again, it is not enough to clear alcohol
from your system by any stretch. You have an organ
that is designed to do this. It's called your liver.
Your liver can clear for an average man, and it varies,
but about a drink's worth of alcohol per hour from
(36:06):
your bloodstream. Don't try. This gets worse the more takes
you have sweating in a sauna, you know, we're talking
less than a hundredth of that amount. It's just not
the way to get alcoholic.
Speaker 3 (36:20):
It's not the hangover here that one hope for.
Speaker 1 (36:22):
No, it's definitely not, in fact, the dehydration that comes
from a sauna. It's probably gonna make things worse alsome thanks.
Speaker 2 (36:29):
Of course, the last thing I wanted to say on
the benefits is I came across what I think was
an extremely interesting study about women with obesity and PCOS
where they did it's a it's a relatively small set.
They did actually a pretty short intervention where they sort
of put them in the hot tub for an hour
(36:51):
a week for eight to ten weeks, and there actually
were a bunch of improvements in blood pressure and other
cholester all metrics, so no improvements in weight, but just
things that looked like, as you said at the beginning,
like a little bit like they had exercised, like similar
to if you had put people in exercise. So, you know,
(37:12):
I think part of what was interesting about that for
me was, you know, I think exercise is great, but
exercise is not always feasible for everybody and is not
something everybody wants to do. And so to the extent
that there's a this is sort of something that could
be helpful in some cases, maybe on the way to.
Speaker 3 (37:29):
Exercise, or maybe in addition to it.
Speaker 2 (37:32):
It feels like there's there's sort of something there that
might be meaningful enough that it's.
Speaker 3 (37:37):
Worth considering for some people. I buy it, okay, but
not all people.
Speaker 2 (37:41):
So what when we sort of talk about are there
people who should not do this pregnant?
Speaker 1 (37:48):
Yeah, yeah, there's always people who should not do everything.
You know. Again, if you're curious, if you're one of
these people, of course, talk to your doctor. But broadly speaking,
both of these hot and cold are mild cardiovass stressors.
So people with pre existing heart disease who are at
risk of heart disease, you know, certainly can be put
at mild risk by going into either of these situations.
(38:11):
People at risk of arrhythmias, particularly with the cold plunge,
and I'll just say it again, I would not put
your face in the water when you're in the cold plunge.
The problem with a rhythmias is that a lot of
people who at risk of them don't know that they're
at risk of them, at least the first time that happens.
And so does make me a little bit nervous. Obviously,
jumping into a cold body of water, as opposed to
(38:31):
like a tub in your backyard has extra dangers because
of that cold shock response. You know, people jumping into
cold lakes can just like go under and not come up,
and it's very hard to find them. Deaths have been described,
so you know this is something to take seriously and carefully.
I will also mention that there have been some studies
(38:52):
if you're a man that is interested in fertility, at
least in the short term, that prolonged exposure to heat
does kill sperm. And so if you know, if you're
you and your partner are trying to get pregnant, it's
probably not the best time to do significant sauna or
hot tubbing. And women who are pregnant that elevated body
(39:16):
temperature can certainly be damaging to the fetus, and so
we don't recommend hot, certainly for pregnant women, and I
probably wouldn't recommend cold in that case either.
Speaker 3 (39:27):
Just disagree.
Speaker 2 (39:29):
Actually, I spend a bunch of time at some point
looking at the cold plunge data in pregnancy, and I
would say, although you know, of course the data is
limited because cold plunging seems terrible and why would you
do it?
Speaker 3 (39:41):
Ever, there actually are.
Speaker 2 (39:44):
There is some evidence on this is actually no real
reason to think that, you know, particularly if you are
a person who generally does this, that you would need
to stop doing it when you were pregnant, which is
not the case of hot dubs and saunas, where the
risk for neeral tube defects, particularly for exposure in the
first trimester, means that that's a no, no.
Speaker 1 (40:03):
Fair enough, fair enough, all right, No, saunas may be
cold plunges, but be careful.
Speaker 2 (40:07):
So my last like risk question that I have always
wondered about is like, can you get frostbite from being
in the like if I get in and I have
some exposed parts fingers, toes for men.
Speaker 3 (40:22):
I mean, aren't you worried your penis is gonna get
frozen off? Honestly? Isn't that a thing I would be worried?
Speaker 1 (40:28):
Well, I hadn't thought about it until just now. Now
I'm worried. It's not my go to every time cheese.
So typically in frostbite, we imagine that it occurs when
the external temperature is below freezing because you have ice
crystal formation so that being said, you can get schemic digits.
(40:55):
So that response to cold is that the blood vessels
in your your superficial blood vessels constrict, and it can
be quite powerful. Particularly there's a phenomenon called Renod's phenomenon.
Many women have experienced this where and I mean men
have it too. It's just more common in women where
you have such severe vaso constriction in your finger typically fingers,
(41:17):
but it can happen in toes two that it's just white.
There's just no blood flow there that can be triggered
by cold plunges. And so many people who do this
routinely actually wear like some rubber gloves and rubber booties
and even rubber boxer shorts. To get to the issue
that you are referring to, Emily, to try to make
(41:38):
sure that those nibbly bits as we call them in
the medical profession don't get exposed to too much of
that cold. Broadly speaking, I think if you're healthy and
you don't have vascular problems to begin with, even some
vaso constriction from the cold plunge that is painful and
hurts is not going to result in the loss of
(41:59):
a digit the way you could if you were, you know,
outside in sub zero temperatures, so you.
Speaker 2 (42:03):
Won't lose your fingers, but your nibblelybits could be uncomfortable.
Speaker 3 (42:07):
Thank you.
Speaker 1 (42:08):
Yes, I'm sorry to use medical jargon.
Speaker 3 (42:11):
Well it's I think we're gonna be using that in
the future.
Speaker 2 (42:16):
Okay, So Perry, what is your one thing takeaway on
cold plunges and saunas for the listener.
Speaker 1 (42:25):
Cold plunges seems like modern day self flagellation. Be kind
to yourself. I don't think it's worth it. Saunas, sure,
go for it, primarily because it's a nice time to
have some time to yourself and relax, which we all
need more of.
Speaker 3 (42:39):
My one thing is similar.
Speaker 2 (42:41):
What I would say is if hot tub sauna on
a regular basis sounds like something that would serve you
emotionally or in some other way, then that seems lovely.
And in fact, if getting in this ic tub in
your backyard would serve the same things and that's a
nice date, that also seems fine.
Speaker 3 (43:02):
Up to the concerns.
Speaker 2 (43:04):
But for most people, I don't think I would invest
in either of these for significant health benefits. There are
a lot of other things I would put on the
list for people first.
Speaker 1 (43:15):
Sounds good. We will be back right after this with
your questions, and we're back with our listener question of
the Week.
Speaker 4 (43:29):
Hi, Emily and Perry. This is Ellie from Toronto, Ontario.
So I'm a parent in my late forties, and I've
been running on about five or six hours of sleep
at night for well many many years.
Speaker 3 (43:46):
So my question is I.
Speaker 4 (43:48):
Function, you know, I mean, I get through my day.
I've convinced myself that I've totally adapted to that amount
of sleep and it's fine.
Speaker 3 (43:56):
But I keep.
Speaker 4 (43:57):
Hearing that chronically not getting enough sleep can kind of
damage your health quietly, and so I'm wondering is regularly
getting this amount of sleep harmful if you feel fine? Like,
what does the research say about long term effects on
things like, you know, like my metabolism or my heart
(44:20):
or my mood, my weight, et cetera. And then I
guess the last pieces. If someone can't realistically get eight hours,
what are the most meaningful ways to reduce the damage.
Speaker 3 (44:33):
Thank you, Emiley.
Speaker 1 (44:35):
I'm so excited about this question because I get to
talk about familial natural short sleep, one of my favorite
and most awesome genetic conditions. So there are people out
there literally who do not need to sleep as much
as other people. Approximately one percent of the population have
this genetic condition called familial natural short sleep. I will
(44:58):
point out that it's not a syndrome or a disease
because it doesn't cause any problems. In fact, it seems
to be quite beneficial. These people need to sleep about
four to six hours a night, they suffer no ill effects.
They might even be protected against Alzheimer's disease. There's some
suggestion there it is inherited through families. But the fact is,
(45:18):
unfortunately that most of us aren't lucky enough to have
the special genetic mutation that prevents demension and makes you
not have to sleep at night.
Speaker 3 (45:26):
How would I know?
Speaker 2 (45:27):
So like before we get into regular people, how would
I know if I had this mutation?
Speaker 1 (45:31):
You might know because you sleep four to five hours
a night and feel completely fine, or at least you
might be. You might suspect. And then many of the
genes are actually known, so if you know, if you
were genotyped, they could detect that you had this variation.
Speaker 3 (45:44):
That is fascinating.
Speaker 2 (45:45):
However, most of us do not have this variation, and
most of us need more than this amount of sleep.
Speaker 3 (45:51):
That this person is getting.
Speaker 2 (45:52):
I mean, I so, first of all, I just think
we underestimate how important sleep is. I think most adults,
especially adults who have jobs and et cetera, kind of
think of sleep like a sort of nice to have,
you know, sort of like a pedicure, right, Like you know,
it'd be great if I could get one, my feet
would look better, but like if I can't get one,
it's totally fine. And I sort of think people should
(46:14):
think of sleep much more like a biological necessity, like
and if you don't get enough sleep, it's like torture.
I mean, sleep deprivation is a form of torture.
Speaker 3 (46:23):
And we know that.
Speaker 2 (46:25):
People's working memory and executive function is affected by even
relatively limited limitations on amount of sleep. So they have
these studies where they'll take away, you know, a couple
hours a night for some period of time, and over
a few days of that, you actually end up with
a level of functioning that's not dissimilar to if you
literally skip the night of sleep. And it's especially hard
(46:45):
on working memory, which is something that when you think
I need to do something and then you go into
the other room and you've forgotten what it is. That's
your working memory, and that's not good if you are
not sleeping enough.
Speaker 3 (46:58):
Yeah.
Speaker 1 (46:58):
I couldn't agree more. It's super important. Most people need
about six and a half to eight and a half
hours a night. People do very a little bit around there,
but you really got to get it in there. You've
got to prioritize it the same as you think about
like getting some exercise or eating well or whatever. It
is a critical thing to focus on, so do your best.
Speaker 2 (47:14):
I will also say, you know, I want to recognize
that it is really hard to get enough sleep and
that for a lot of people listening to this, you
probably have multiple jobs and multiple children. And so this
is partly you know, giving yourself a break and saying like, hey,
if I'm not in bed you know at ten o'clock
fully asleep and up at you know six, like Brian Johnson,
(47:35):
like it's okay, Like you're not going to immediately die.
But it's also saying, you know, this should be something
you prioritize, and so thinking about, you know, what is
feasible for me to improve my sleep. I think that's
something that we should care about. And I think at
some point we should do a whole episode on the
science of sleep, because I love the science of sleep.
Speaker 3 (47:54):
Every animal sleeps, It's so interesting.
Speaker 2 (47:56):
Dolphins sleep, has their brains at a time while they're swimming.
Speaker 3 (48:00):
I'm going to pull out so many great facts for you.
Speaker 2 (48:02):
So, Perry, do you have any quick tips for better
sleep if someone wants more sleep?
Speaker 1 (48:07):
The standard sleep hygiene stuff here, which is, you don't
want to drink caffeinated beverages typically after like four pm.
You might not even want to drink any beverages as
you approach eight o'clock nine o'clock at night, just so
you don't have to wake up in the middle of
the night to pee. We want people sleeping in dark,
quiet rooms as much as possible. Those noise machines and
stuff can actually disturb sleep a little bit if you
(48:28):
are an allowed environment. Ear plugs are awesome if they're
comfortable for you, and the bed is a place to
sleep and have sex, not to eat and watch TV
and be on your phone and whatnot. I'm okay with
reading in bed, but I would read an actual book
as opposed to a phone, because that blue light that
comes from the screen can actually keep you up a
(48:48):
little bit.
Speaker 3 (48:49):
That's it.
Speaker 1 (48:53):
Join us next week when we ask what's the deal
with the blockbuster weight loss drugs GLP ones.
Speaker 2 (49:00):
Wellness Actually is produced in association with iHeartMedia.
Speaker 3 (49:03):
Our senior producer is Tamar Avishai.
Speaker 2 (49:06):
Our executive producer at iHeart is Jennifer Bassett. Our theme
music is by Eric Deutsch, and our content is for
educational purposes only.
Speaker 1 (49:14):
If you like the show, help other people find us.
Leave a rating and review on Apple Podcasts or your
podcatcher of choice, and help us spread the word about
the show. Don't give the TikTokers all the power, and
don't forget we want to hear from you. Head over
to Wellness Actually dot fm and leave us a question
for our mailbag or suggest a topic for a future show.
Speaker 3 (49:34):
We'll let the influencers have the last word, all.
Speaker 5 (49:36):
Right, guys. So I am three weeks into cold Plunging,
and I'm going to explain to you, guys the differences
I'm noticing and whether I think this is worth it
or not for you guys to go out and get
a cold plunge for yourself.
Speaker 1 (49:46):
Or build one.
Speaker 5 (49:47):
But I've been doing it for three weeks now, every
single morning, and I will tell you the very first
thing is that I highly underestimated how much I was
not going to want to get into that cold plunge
every day
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