If You Sweat More, Do You Burn More Calories?

Get all of your preparation information in this episode of Fitness Disrupted! What is the purpose of sweat? What does it mean if you sweat a lot? Let Tom explain sweat's function, and provide some surprising science surrounding perspiration.

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Episode Transcript

Speaker 1 (00:00):
Welcome to Fitness Disrupted, a production of My Heart Radio.
I am Tom Holland and this is Fitness Disrupted. If
I know anything about anything, I know a little bit
about sweat. Actually I know a lot about sweat. If

(00:23):
you're still listening, That's what we're gonna talk about today.
And the general question I get about it is if
you sweat more, do you burn more calories? Other ways
of putting it, people will ask me, you know, Tom,
if I'm not sweating after a workout, does that mean
I didn't work hard? So that's what we're gonna talk
about today. We're talking about sweat, what it is, what

(00:47):
causes it, and how it's connected to exercise. I'm to
give you the science, give you a couple of studies,
and it's gonna actually surprise so many of you, and
give you a question shortly that's gonna surprise you, and
it's gonna really surprise most of you when it comes
to sweat rate. But it's all good news and it's
all science based and let's just let's just get into it.

(01:10):
So when I say I know something about sweat, uh,
in several different areas as far as my fitness career
over the years. Uh. First of all, I've raced in
so many ridiculously hot and humid climates. I did iron
Man Malaysia, which was a hundred and four degrees and
I believe it was percent humidity. It was just brutal.

(01:35):
During the run, I would run across the street to
try to get that little bit of shade, even though
I was running farther. I anything to get out of
the sun. It was brutal. Iron Man China the same thing.
I did the Honolulu Marathon years ago, amazing in December,
Christmas music playing, and if memory serves, we started at

(01:58):
four thirty in the morning, believe because obviously they wanted
the race to be run and finished as soon as
possible before the hottest part of the day. I did
the Hawaii Run to the Sun incredible and actually went
from heat to cold because that race was from sea
level to the ten thousand foot summit of Mount holy Aklo.

(02:20):
The greatest event, one of the greatest events I've ever done.
And I've done the Hawai iron Man several times as well,
so just a lot of experience in the heat and sweating. Okay,
And then when I started doing fitness videos many years ago,
my original fitness videos I shot in real time. I
did not edit, I did not stop the cameras, and

(02:42):
I did not wipe away the sweat. And that was
a good and a bad thing. There were people who
said they were so appreciative of the real, just video
aspect of it. I I even left in, you know,
some stumbles when I didn't do something perfectly. I did
stop the camera and redo it because when I was fatigued,

(03:02):
I wanted people to see that, and when I was sweating.
I mean, it has always blown me away. When you
see some of these videos and you're like, that person
is not sweating at all. Guess what many of them are.
And actually, when I give you that one thing about
sweating and fitness level, it will come back to this.
They are getting toweled off NonStop, and that's just that's

(03:23):
not helpful. So you're sitting there drenched in sweat. This
person hasn't dropped, you know, one little tiny droplet on
the floor, and you're going, what's going on? So that's
that's a big deal. And actually when I did so
those are my own videos. And then I did do
a bunch of others, including the ABS diet workout, shot
it in l A. My sweat rate so crazy, and

(03:44):
in between breaks they didn't want to sweat. They'd a
huge two basically an air conditioning tube, probably like four
ft across, and I would just sitting it to try
to cool down because uh yeah, my sweat rate is
up there. And finally, you know, when used to teach
different classes and especially group cycling, the puddle underneath my

(04:08):
bike enormous. I used to say that, you know the
front row, I'd warn the class. I'd say, this is
like sea World, this is the splash zone. They should
have it marked off and even behind plexiglass, because because
I sweat. And we're gonna talk about why and how
it's related to fitness level and all the other factors.
All right, So here's the question I'm gonna pose to you.

(04:30):
Who do you think sweats more? Is it a person
who is really fit, or is it a beginner exercise
or someone who is just starting their fitness jurdy, who
do you think sweats more? Take a quick break. When
we come back, I'm gonna give you the answer, and
it's going to start the whole conversation about what is
connected to sweat rate and do you have to be

(04:52):
drenched in sweat for it to be a hard workout,
and does that correlate with the amount of calories you burnt?
Quick break, We'll be right back. I gotta say I'm
enjoying this topic sweat. I don't think I did say

(05:18):
that their work criticisms of my original fitness videos because
I was so drenched and sweat it was a turn
off to some people. I get it, And you know what,
I was willing to lose those people. I was willing
to lose them for the reality of it, and that's
just who I am. But I get it. It could
be a little overwhelming. So let's let's just talk about exercise.

(05:40):
So exercise and how it's correlated connected to sweat and
calories and all that kind of stuff. So really quickly,
let's do the science. So, during exercise, your body produces heat, right,
and a significant amount of energy is wasted and then
it's released as heat from your exercising muscles. Okay, you

(06:00):
have an increased rate of metabolic heat production. Your your
body is getting warmer, your core temperature is rising, you
have an increased internal body temperature, and so your thermoregulatory
system says, hey, wait a minute, we gotta cool this
back down. I want it back to homeostasis. So how
does that happen. It's gonna start to activate its heat
dissipating mechanisms as they are called. Okay, one of those

(06:25):
is sweating. When your body temperature rises, your ekrone glands
secrete sweat, and it's the evaporation of this moisture that
helps you cool off. When it evaporates from your skin,
it transfers the body's heat to the air. And because
water has a high latent heat, which is essentially the
heat required to change liquid water to vapor. Back back

(06:48):
to chemistry class, right, this process does a pretty good
job of cooling down the body does It does a
great job as humans. This is one of the great
factors that Dr weber Men talks about. Dr Lieberman from
Harvard Born to Run quoted does all this incredible research
into running, an exercise and evolution, and one of the

(07:10):
major reasons he cites four us being born to run
is how great our thermoregulatory system is. We were persistent hunters.
We would run down any animal we wanted to because
they do a really bad job of cooling themselves. Dogs panting,
it's not a really good way to cool yourself down.

(07:31):
So the evaporation of sweat, and if you actually study evolution,
how our body change. We should have a lot of
hair now we don't. And part of that is the
thermoregulatory system. Kind of going off on a tangent here,
but I love this stuff. Okay, So how what what
is it related to? So we sweat? What does that
have to do with I'm gonna give you five basic

(07:53):
things that are involved when it comes to sweating during exercise,
and here they are. So number one, you're each your
age is a factor in how much you sweat. Generally speaking,
younger people sweat more than older people. Okay. Uh. One
thing that always has just tortured me is seeing you know,

(08:14):
an older person, let's say in New York City. It's
it's August, it's nine two degrees and they're in a
three piece suit and they're not This guy is not
sweating at all. It's always blown me away. But that's
one of the things that's one of the criteria your age.
Generally speaking, younger people sweat more than older people. Just

(08:37):
to quick aside to uh, very short stint right out
of college, tried the Wall Street thing living in New
York City fifty six and second would put on a
suit August, just a couple of months in the summer,
by the way, worst time ever or best time, because
so short lived. And part of the reason was to
put on a suit because I was already had such

(08:58):
a high sweat rate, already been next a sizing for
a really long time and and starting to teach and
all that kind of stuff. Back then, Uh, it was
pure torture. I have to go down and anyone who's
lived in New York City in the summer knows what
I'm talking about. And you have to go down three
stairwells into the bowels of New York City and it's
like nine degrees and the subway cars are filled and

(09:21):
you have to wait for three before you can even
get on one, and that's packed. It's just horrific. So
my point is, you know, your age has something to
do with it. But even back then I had a
high sweat rate. And I'll explain why shortly so age.
Now gender and this we've we've all seen. You've probably
seen it. You probably have have you know, guessed it

(09:41):
as common sensical. Almost men tend to sweat more than women.
We talked about women glistening more than sweating, right, part
of that is due to body size, So men generally
are bigger, are way more than women. So that's part
of the re and the gender differences. And that leads

(10:02):
to number three, which is weight. Have your people tend
to sweat more because their bodies generate more heat. You're
you're pushing more mass, you're moving more weight around, and
you're generating more heat as a result. Okay, genetics, so
here's kind of that. This is one that's tougher right
to to quantify a lot of it comes down to

(10:25):
what we'll call biological variation. Some people just sweat more
than others and some people don't sweat as much, and
that is due to genetics. But just like weight gain
and things like that, yes, genetics play a role, but
as you'll see, those factors can change and you'll see

(10:47):
how it's related to fitness shortly, and finally, number five,
and this is super important. I'm gonna get into this
a little deeper. Because of that, your environment plays a
huge role in how much you sweat. So this goes
to the temperature, and this goes to the humidity. As
the top two to start it off your environment, right,

(11:09):
So back iron Man Malaysia, it wasn't even the temperature,
which was brutal. There was the temperature actually a huge part,
but humidity is a huge factor dew point. So when
the temperature is high, when the dew point the humidity
is high, that's a huge problem when it comes to evaporation. Okay,

(11:34):
the rate of which water, and in this case we're
talking about sweat evaporates depends on how much water is
already in the air. On dry days, it's gonna evaporate quickly,
all right, and that's going to carry the heat away faster,
and you're gonna be able to exercise longer. On humid days,
the air is already saturated with water, sweat is going

(11:56):
to evaporate more slowly. And the simplest way of putting
this that I have used this line for years is
that every drop of sweat that hits the ground essentially
is a drop of sweat wasted when it comes to
cooling you down. It didn't evaporate, all right, It's not
to say it's completely wasted, but my point is well taken, right,

(12:20):
is that that goes to humidity. Um Oftentimes so we
want to sweat and its counterintuitive get into it, and
we wanted to evaporate. The evaporation is where the cooling
really happens. And humidity is a problem when you study
for personal trainer exams, going way back, and they talk

(12:43):
about temperature and humidity which is worse, and they'll give
you certain numbers. Again, it's the humidity oftentimes depending on
what temperature they're compared against, but by and large, because
the sweat is not going to evaporate, that is a problem.
All right, So now give you a little more science.
It's kind of fun. Again. It's going way back for me,

(13:05):
and this is fun. The four types of heat loss.
You're gonna see how you can manipulate these in your environment,
especially if you're working out at home or taking it outside.
You're gonna see how this all ties in to sweat
and why you may be sweating more or why you
may be sweating less. Okay, so four types of heat loss.
There's convection, there's conduction, there's radiation, and there's evaporation. So radiation,

(13:30):
that's your body at rest. It's the body's primary method
for getting rid of heat, for discharging heat, and it's
a cooling process by which your body loses heat by
thermal radiation. Okay, And it's the transfer of heat from
one object to another without any physical contact. So most
likely it's happening right now. Is you're listening to this, Well,

(13:50):
a lot of people are walking and doing other things.
So but yeah, that is the body's primary method for
getting rid of heat, especially at rest. Okay. Conduct action
it's the process of losing heat through physical contact with
another object. So you're sitting in a metal chair, you're
losing heat to the object you are physically touching. Convection,

(14:11):
Now here's something we can start to understand when it
comes to sweating the process of losing heat, and this
is through the movement of air or water molecules across
your skin. So now we're talking about swimming. We're talking
about water. Okay, water amazing at changing the body's temperature

(14:31):
right depending on how hot or cold the water is.
And now convection, we're talking about fans and we're talking
about wind. So let me just go there real quickly.
What people will say, it's running outside the same as
running on a treadmill. Here's something that is you know,
they'll talk about the mechanics of the treadmill and and

(14:53):
all that kind of biomechanical stuff, and oftentimes what's left
out is the wind or lack thereof. So if you
don't have a fan on you and you're inside and
you're running on a treadmill, it is gonna feel a
heck of a lot harder, not only for the physical
aspect of being on a treadmill and going nowhere. So

(15:14):
you've got the mental part, and then you've got the intensity.
That level is increased if you don't have air across
your body. So you're outside and you've got wind, you
do your body is cooling itself down better again, depending
on the temperature in the humidity obviously, but all things
being equal, you've got airflow. And when you're down in

(15:36):
your home gym or you're in a studio, you know,
at a gym somewhere and the airflow is nil, that's brutal.
And when I do my indoor workouts, I have four fans,
four fans hitting me from all different directions, and I
almost cannot get into workout indoors without a fan because

(16:00):
as I'm gonna heat up so fast and I need
that cooling, and that is why or one of the reasons.
Many equipment manufacturers now are building the fans right into
things like the treadmill console. Okay, so there you go, convection, conduction, radiation,
and finally evaporation when we were talking about at the start.
One final time. So you got the blood underneath your skin, right,

(16:21):
and it's cooled by means of an endothermic reaction, and
we go to the science and that allows the sweat
to evaporate. And one final time. It's because the transfer
of matter from a liquid to a vapor requires heat energy.
The energy is drawn from the body, heat is pulled
out of the nearby blood and skin, and the body cools.

(16:44):
So now I throw in this sixth one. This is
the one I was talking about. This is what's gonna
blow your mind for the most part because it's so counterintuitive.
And now I feel like American idol. But we're gonna
take one final break and when I come back the
sixth reason that I'm sure you probably have no idea about,

(17:09):
and you're gonna say that can't possibly be right, Alright,
one final short break when we come back. This is
what it's all about. This is what shows all about.
The sixth reason you sweat or don't. We'll be right
back and we are back talking sweat. The greatest job

(17:35):
in the world where that's what I get to talk
about things like sweat now here we are it's completely
counterintuitive fitness level. That question I asked before the first break,
who do you think sweats more fit person or a
less fit person? Here it is fit people tend to

(17:56):
sweat way more than those who are less fit, and
there are two things involved. They not only sweat more,
they sweat earlier. But now, if you think what we
just talked about, the little lesson you had, well evaporation
cooling the body. Let me throw this in said in

(18:19):
many other shows. Our bodies are such smart machines. They adapt,
They adapt really quickly. So fit people sweat earlier and
more than less fit people because the body has learned
to cool itself quicker, to be more efficient. All right.

(18:43):
Research indicates that as you increase your fitness your body's
heat regulating systems again, they become more efficient, They cool
you down faster, and they allow you to work harder.
Don't read about this, you don't he or this. So
your high fitness level allows you to exercise at a

(19:05):
higher workload, which generates more heat, and in turn, you're
gonna sweat more. So we're gonna take all of this
and now pull it all together, right, Gonna throw in
some studies, throw in some studies, and then I'm gonna
give you the takeaway what it means probably kind of confusing.
Right now. That's sixth one, and we gave you five

(19:26):
and then I threw in the sixth. Was holding that
one back for that reason because it's everything we're talking about.
It's everything we're talking about. So give you a great
study often cited about this, and it actually goes to
two of the factors I just talked about, fitness level
and the sex differences. Okay, so title of study sex

(19:49):
differences in the effects of physical training on sweat gland
responses during graded exercise. Yes, during a graded exercise. This
was an experimental physiology October two, all right, So basically
thirty seven subjects. You had ten trained and ten untrained
females and eight trained and nine untrained males, and they

(20:11):
were on a stationary bike for sixty minutes at three
different workloads. And what were they looking for? They were
trying to see the sex differences in the sweat land
response to changes in exercise intensity in respect to the
subject's physical training status. Okay, take away. The local sweating

(20:31):
rate on the forehead, chest, back, forearm, and thighs was
significantly greater in the trained subjects than in the untrained
subjects of both sexes, and it was concluded that training
improved the sweating response and a sex difference was observed
in the degree of improvement in the sweating response due
to physical training. So that just supported two things. That

(20:58):
you sweat more and sooner the fitter you are, and
that men tend to sweat more than women. Okay, so
I give you one more study because it kind of
it will play in all this as well. And this
is why you might want to exercise in the heat.

(21:18):
And they've got to be careful, and you know, a
whole another show on how to be safe and how
to do that. But here's what happens when you exercise
in the heat, and it's one reason that people get
fitter and sweat sooner and all those kind of things.
So title heat acclamation Improves Exercise performance. That is the
name of the study. Journal of Applied Physiology, October two

(21:40):
thousand ten. So heat acclamation improves exercise performance. It was
a heat training study with twenty athletes, and the study
was looking at twelve train cyclists who are performing tests
of maximum aerobic power, time trial performance, and lactate threshold.
And they were doing these in both cool and hot
environments before and after a ten day heat acclamation program. Okay,

(22:05):
and there were eight others in the control group. That's
how it comes out to twenty in the study. And
after only ten days of heat acclimation, they showed remarkable
gains in v O two max, increased blood plasma volume,
and the body's ability to cool itself. And that's what
we're most interested in right now, the body's ability to

(22:25):
cool itself. But they're also we're gained. So this is
one reason when you see that person a friend of
yours who's out exercising and challenging environments, all of that
goes into increased fitness level. And part of that is
the body's ability to cool itself. So when you cool
your body sooner and to a greater degree, you can

(22:48):
push higher intensities. So that's a good thing. Okay, So
let's bring it all together. So you're going so what
you're telling me, Tom, is that I'm not sweating, so
I'm not working hard enough. Absolutely not, absolutely not. So
if you're not sweaty after a workout, could be let's

(23:09):
let's say it could be the environment. If you're always
exercising in a pretty cool place and a place where
there's you know, you've got the fans or you've got
your exercising outside and you have wind that's gonna be
cooling you down, so you're not gonna be sweating as much.
If you're a female, if you're a young female, that's
part of it. Even if you're an older female, your

(23:30):
sex plays a role. And there's that genetic factor I
talked about. But here's the thing. You can use that
sweat rate over time. If you start to really exercise
and you start to push yourself more and more, you're
gonna see that change. Most likely to some degree, may
not be huge. You may not see it at all though.

(23:53):
And here's the final takeaway. This is all we need.
And actually I'm gonna quote which I really do, but
I like her and she's another exerise physiologist American Council
on Exercise. I thought Jessica Matthews put it perfectly everybody
is different and sweats differently, and how much or how
little you sweat doesn't equate to the number of calories
you burn. Okay, so there's the takeaway. We were the

(24:17):
whole show is about. Is it the amount of sweat?
Is there correlation to calories? Well, yes and no, yes
and no. So you go don't say yes and no.
That that just leaves here's the thing. Science says. What
if you feel you are working hard, you are working hard.
That's what matters. My wife will be doing a workout

(24:41):
downstairs and she'll start throwing numbers out and just say,
I feel like this should be higher in this. And
I'll say, and she's on an indoor bike by the way,
I'll say, did you feel you were working really hard?
And she'll say yes, And I'll say, then you were. Now,
if you're doing workouts that on a scale of one
to ten, you're always at maybe a four of five,
You're not gonna be sweating. For that reason, there's still

(25:05):
value in that workout. It depends on your goals, depends
on your fitness level. You may have injuries, you may
have health issues, you may be on medication. So this
is one of those gray areas, but but not so. No,
if you are pushing yourself super hard, it doesn't matter

(25:26):
if you sweat if that's what your goal is. If
you're saying, I know I worked out hard, but I
wasn't sweating, or you say I went for a walk
and I wasn't sweating. Well, again, now we know temperature, humidity,
gender age. I'll leave you with this when it comes
to the type of workouts you should do. This is

(25:48):
why I would ideally like you to mix up your
cardio workouts. Some days you go steady state. You spend
a lot of time at that level five out of
ten endurance training for everybody, including professional athletes. You build
that base, you spend a lot of time there, and
then shorter amount of time you do your little intervals.

(26:09):
You take a class maybe and you push it. But no,
the sweat rate does not correlate to the value of
your workout. But know that if that person next to
you is is has a puddle underneath and they're not
on the heavier side, that generally means that that person

(26:31):
is fit, their body is get is really good at
cooling it down, and that's what's so counterintuitive. But generally
speaking to that person. Those are, in my experience, highly
trained iron Man marathon or's ultra marathon. There's other sports
they've been doing it awhile and their bodies have adapted accordingly.

(26:55):
Does not mean that your work at is any less valuable.
It's about consistency. It's about mixing up your intensities. And
that's pretty much it. If you're consistent, and if you're
mixing it up somewhat to start at the very least,
then you are doing the right thing. You don't walk

(27:16):
out and and uh, you know, grade your performance on
how much sweat is there. Final story, when I was
teaching many many years ago New York City spin classes,
people used to sprint out because it was a hot
proom and weigh themselves and they would have lost a
couple of pounds and that made them happy, and I

(27:39):
would explain to them, that's water, that's sweat. It's a
perfect way to end the show, to show you that
the scale is not to be all end all. Because
I sweat out an incredible amount of fluid. I will
lose three to four pounds in an hour in a
hot environment, and that's crazy amount of sweat. But it
also shows you that the scale. It's just one tool

(28:03):
to measure our success. And it's a it's a very
it's low on that totem pole as far as uh
what health and and you know how effective your workout
is because as soon as I drink that water back in,
that weights going back on. All right, So if you
feel you are working hard, you are working hard. If
your goal is consistency, then that's all that matters. Sweat, Yes,

(28:28):
I often say if you are sweating, that's a good thing.
If you're not sweating, that's okay. Be consistent, mix up
your routine and enjoy what you're doing enough. I hope
you enjoyed this episode on sweat. Now you know why
your instructor maybe has that enormous puddle underneath them, and

(28:52):
you should be happy. Say, hey, that instructor is most
likely fit and they're working hard to all right. So
hope that clarifies a little bit. Obviously the confusion part
is the fitness level. But let me go over at
one final time. Age Okay, your age, your sex, your weight,

(29:15):
your genetics, and your environment. And now you know how
to manipulate your environment to work out harder if you
want to. If you're working out inside. Get those fans.
It will make it exponentially easier for your cardio sessions,
for just about everything. To cool it down, You're most
likely going to work out longer, You're gonna enjoy it more,

(29:35):
and you feel better because it's not as intense, your
body will be at a lower heat level and that's
a good thing. Oh right, thank you so much for listening.
This was fun. I hope you enjoyed it. I am
Tom Holland if you enjoy the show, please rate it
even you know, just rate it. And if you have
rated it already, thank you. Questions comments, if you have

(29:57):
a place to leave them where you're listening, please do
And you can contact me, get in touch Tom h
Fit Twitter as well as Instagram, Tom h Fit, Fitness
Disrupted dot com. You can email me through that website
learn more about be there as well and hashtag fitness
Disrupted and I will see those on social media. And finally,

(30:20):
a new book coming out in just a couple of weeks.
You can preorder it. It is the micro Workout Plan.
Really excited, goes to everything I've talked about here my
sixth book, and you can get that in your hands
in just a couple of weeks, if not sooner, so
the micro workout plan. Thank you so much for listening.
I have the greatest job in the world, and there
are three things I talk about at the end of

(30:42):
just about every episode because it's so important. Three things
we can control how much we move, what we put
into our mouths and our attitudes, and that is awesome.
I Am Tom Holland. Believe in yourself. Yeah. Fitness Disrupted

(31:04):
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