November 11, 2022 • 18 mins
Astronauts undergo rigorous training to prepare their bodies and minds for space, but once they arrive, the experience of being weightless thousands of miles above Earth is like nothing they’ve ever felt before. Join host Anahad O’Connor as he learns from former NASA astronaut and International Space Station commander Leroy Chiao about what it’s like to work and sleep in space, including the dramatic changes the body endures over the course of a mission. Sleep science researcher Dr. Mathias Basner joins to share how zero gravity and noise can impact everyday activities like resting in space.
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Speaker 1 (00:02):
Three two.
Speaker 2 (00:06):
Space flight definitely changed me.
Speaker 3 (00:07):
I think it has definitely has an effect on everyone
who goes up there, even for a short mission. So,
you know, just looking down at the Earth, I mean,
it's just so beautiful and colorful and looks extremely peaceful.
Speaker 2 (00:19):
Right you're.
Speaker 3 (00:24):
Eighty million kid two point eight.
Speaker 4 (00:27):
Very few people have viewed Earth the way Leroy Choo has,
from over four hundred kilometers above the planet's surface and
cruising at an unimaginable seventeen thousand miles per hour. Leroy
is a chemical engineer and a former NASA astronaut who's
been to outer space on four separate missions, racking up
(00:48):
two hundred and twenty nine days in space.
Speaker 3 (00:52):
One of the things that a lot of people find weird,
and I found a little weird too, is you're not
sure what to do with your head and your neck.
You know, because you're on Earth you're used to feeling
that pressure on your head against a pillow, and in space,
of course, you're just kind of I mean, we actually
do have like a little foam block at the top
of the sleeping bag that you can act as a pillow,
and there's a cloth a fabric strap with velcro that
(01:14):
you can strap against your forehead if you need that
pressure against the back of your head to fall asleep,
and I don't think anyone really uses that.
Speaker 4 (01:21):
Spending that much time in orbit means that Leroy and
his fellow astronauts will definitely see the effects of that
environment on their bodies, particularly when they're trying to sleep,
which is even more of a challenge in space than
it is on Earth. The lack of gravity effects astronauts spines,
their brains, and even the amount of fluid build up
in their nasal cavities, just to name a few of
(01:43):
the challenges. All of these things just make it even
more difficult to get good rest on the final frontier.
Speaker 3 (01:50):
Sleep is not only important when you're really young, but
it's important as a lifestyle, even as a professional to
make sure you get enough sleep so that your brain
can develop to its full capacity. And certainly, anyone in
any position where you have to perform, you know that
you performed best obviously when you've had good sleep and
good rest. So sleep is definitely an important thing, and
(02:12):
it is a challenge in space.
Speaker 4 (02:15):
Beyond the expected challenges of sleeping in space, Leroy experienced
a sort of jet lag as he first embarked.
Speaker 3 (02:23):
So we kept the laboratory running twenty four hours a day,
and so that meant that four hours after launching into
space for my first time, I had to go to sleep.
And so imagine being so excited to be in space
for the first time, looking at the air floating. You know,
we're in this weird environment. Feeling a little weird because
you know you're floating and you're in space, and there
are all these physiological changes happening in your body.
Speaker 4 (02:44):
Anyway, the biology and functions of the human body have
been shaped in part by its evolution in the gravity
of Earth. So how does an astronaut's body, having escaped
that gravity, adapt to life in a spacecraft speeding through
the vacuum of space. Today we're going to explore what
(03:05):
it's like getting rest for our bodies in the ultra
hostile environment of outer space, and how the absence of
gravity and abundance of radiation affect the delicate mechanisms that
allow our bodies and our brains to power down and recharge.
On this episode of Chasing Sleep, Sleep, the Final Frontier. Hi,
(03:32):
I'm Anahad O'Connor, and this is Chasing Sleep and iHeartRadio
production and partnership with Mattress Firm.
Speaker 3 (03:47):
Sleep in space is pretty weird, you know, especially the
first time to get up there. Once we launched into space,
I have to say we were kind of pretty worn
out by the time we did fly. And that's kind
of a joke among us, or not especially those of
us who fly on the Space station, which is not
really a joke. It's like, you know, you're ready to
go fly when you're completely exhausted, and so, you know,
(04:10):
not necessarily the best way to launch into space.
Speaker 4 (04:12):
Right, So you're high above the Earth's atmosphere in space,
a million things going through your mind and all sorts
of different environmental effects happening to your body. What exactly
is it like to sleep up there?
Speaker 3 (04:26):
We had sleep stations on that flight because we were
two shift operations, which meant we had kind of little,
you know, little closets, if you will, hate to use
this word, but they were kind of like little coffins
that we could get into and slide the door shut
so it would be dark, and put ear plugs in.
Speaker 4 (04:44):
Leroy continued to tell the story of his first time
sleeping in space, getting to the obstacle that I find
most interesting zero gravity.
Speaker 3 (04:52):
And so I got into my little bunk after I'd
taken my sleeping pills, and it was dark and had
my ear plugs in, and I knew the orientation of
the Space Shuttle. Usually it was always the belly of
the shuttle facing the Earth, so I knew the orientation
of the shuttle. I knew my orientation inside of that
dark sleep station, and I was laying on my back.
Although I was floating, I wasn't really laying. I was
(05:14):
just floating in there in a sleeping bag, and I
kind of felt like laying on my side, and it
didn't make any sense whatsoever. But I rotated ninety degrees,
and in my mind I knew I was on my
side relative to the Earth. Didn't make any difference because
I was floating. And then I fell asleep.
Speaker 4 (05:29):
So just describing these sleep closets seems like an interesting
place to have to squeeze into. For rest, are there
multiple astronauts in each bunk? And exactly how tight is
the space on a bed up there in space?
Speaker 2 (05:44):
It looks like a big box.
Speaker 3 (05:46):
Okay, So you slide the door open and you kind
of get yourself inside, and then there's three other people
beneath you if you're on the top right, but you're
all separate.
Speaker 2 (05:53):
You're on your own little box.
Speaker 3 (05:55):
And there's airflow, so you got plenty of ventilation, so
you don't, you know, build up carbon dox and all that.
But the sleeping bag's in there, and it's just kind
of floating in there. There's not much room. There's room
for nothing else except you, basically. So one part about
being an astronaut you can't be the slightest bit claustrophobic,
and that doesn't work out.
Speaker 2 (06:14):
But it's not that bad. It's not uncomfortable.
Speaker 4 (06:17):
Maybe it's not uncomfortable, but there's a reason it takes
months of training just to get used to sleeping in
those quarters. And beyond the training, Leroy explained how extensively
he and his fellow astronauts were monitored for sleep and
for other medical conditions.
Speaker 3 (06:31):
So, for example, on that same first mission, I had
to wear an actigraph during my sleep period. It was
a little thing I had to put on my wrist
and it was just monitor. It was trying to get
a handle on how well I was sleeping, how restless
I was, how long it took for me to stop
moving around and go to sleep, and then during sleep
how much I moved around? So they were collecting data
like that. There are also journals that you that you
(06:54):
could keep on your part of that was your sleep quality?
How was your sleep quality? Anecdotally for myself, it seems
like I need a little less sleep in space.
Speaker 2 (07:04):
I don't know why.
Speaker 3 (07:05):
It just seems like maybe I need about an hour
less in space, or I would wake up maybe an
hour earlier than I might hear on the Earth and
sleep was okay.
Speaker 4 (07:14):
The struggle to get good sleep and outer space may
not be easy, but Leroy told me about plenty of
moments that made all the hard work well worth it.
Speaker 2 (07:23):
Yeah.
Speaker 3 (07:23):
I think the most wow moment of my space flights
was on my third flight. We were on the second
major assembly mission of the Space station program, and during
that time I was doing a spacewalk, one of the spacewalks,
and my boots were attached to the robotic arm of
the Space Shuttle and I was being moved from one
work site to another, and during that transition of several minutes,
(07:45):
during a good part of it, I was face down
towards the Earth and I couldn't see the space station
or the space shuttle out of my peripheral vision, and
so I was looking straight down at the Earth, watching
the clouds and the continents roll by, and I felt
like a satellite flying over the Earth was probably the
most amazing, you know, few minutes of my career.
Speaker 4 (08:07):
We'll be right back after a brief message from our
partners at Mattress Firm, and now back to chasing sleep.
The moment the human body enters space, a place we've
definitely not evolved to be, our bodies inner mechanisms start
(08:28):
to change.
Speaker 3 (08:30):
We evolved here on Earth, so life generally likes where
it evolved, and so humans there are a number of
biomedical things that happened to us in space, and none
of them are good. A lot of people have a
little bit of congestion because in space there's a fluid
shift where you're no longer have gravity pulling fluids down
into your legs, so you have a fluid shift, and
(08:50):
even though your body tries to equilibrate that, in fact,
the average person loses about two liters of water in space.
You know, you carry about two leaders less water in
space when you're floating around, So imagine one of those
big soda bottles. That's how much less water is in
the average person. But nonetheless you still feel a little
bit full headed, a little bit like you're laying on
(09:10):
an inclined head down, and so that can make you
feel a little bit congested. And so, you know, that
was something I was aware of during my sleep, is
that I couldn't breathe as easily through my nose, you know,
and sometimes that would wake me up or something.
Speaker 4 (09:27):
Leroy has amazing firsthand insight into the challenges that astronauts
face and the techniques to overcome them. So to better
understand the technicalities behind how space is affecting our bodies
and brains, I sat down with doctor Mattias Bosner, a
professor of psychiatry.
Speaker 5 (09:44):
I joined the German Aerospace Center actually the Flight Physiology division,
and was actually hired to investigate the effects of aircraft
noise on sleep. Was the largest study ever that was
done at the time at the German Aerospace Center. Stayed
at the German Aerospace Center for te years, studied a
lot of sleep, then came to the United States and
(10:04):
did a lot of work in spaceflight and in astronauts.
Speaker 4 (10:08):
Doctor Mattias Bosner broke down exactly what's going on in
and around the bodies of astronauts that makes it so
hard for them to sleep.
Speaker 5 (10:17):
We also see some volume shifts in the brain and
the volumes that carry the cerebrospinal fluid they actually extend
doing long duration spaceflight. And then there's the radiation, which
is not a super big deal on the ISS because
it's still in a low Earth orbit and it's within
earth magnetic shield. But once we venture out of our
(10:39):
lower Earth orbit, you know, back to the Moon or
to Mars, radiation becomes a major issue. And we actually
generated predictive models for NASA looking at all the different
environmental stressors on the ISS, and radiation was one that
was consistently showing up and that it was affecting cognitive performance. Oh,
(11:00):
they're still you know, in that protective environment magnetically, but
then there's also the nutrition is different. On the ISS.
You have oftentimes elevated carbon dioxide levels that can affect performance.
Sometimes you know, lower oxygen levels. You have just the
psychological stress related to living in an isolated, confined, and
(11:24):
extreme environment with a threat to life component.
Speaker 4 (11:29):
These changes on your body can be very jarring. For
first time astronauts. But with enough time, incredibly the human
body begins to adapt, including changes to how our brain functions.
Speaker 5 (11:42):
There is a lot of adaptation going on, both physiologically
but also from a brain perspective, because you know that
gravity vector is gone, and you know your brain kind
of has to rewire itself or reweight the different neural
connections to make sense of this.
Speaker 2 (12:01):
You know, for example, the visual.
Speaker 5 (12:03):
Input becomes much more important now because you know, our
vestibular system that tells us how we are oriented in
space is no longer working. Basically it's switched off, right,
So there's a lot of brain plascicity going on. But
also you know, because of that, nausea is a big
problem during the first you know, one or two weeks,
(12:23):
and you know there's a medication for that as well.
Or back pain is another big issue. You know, astronauts
spines are actually extending because you know, we don't have
that gravity vector, and you know the spine is not
compressed when we're walking around.
Speaker 4 (12:39):
It's pretty interesting how studying something that might seem as
foreign as an astronaut sleeping in space gives us great
insight into how our bodies work down here on Earth.
I asked Mattias what other info he was able to
discover for US earthlings while studying the sleep of astronauts.
Speaker 5 (12:57):
We did this study in twenty four astronauts measured their
perform moments and we asked them questions about their sleep
and how they felt, etc. But at the time we
didn't have the environmental data from the International Space Station.
It was actually very interesting to see which variables were,
you know, showing up. And I already mentioned the radiation
that's not that relevant on Earth, but CO two, for example,
(13:19):
is one of the factors that plays a role. And
we just did another study here on Earth in bedroom
of participants who were wearing like an actigraph which is
a fitbit like device, for fourteen consecutive nights or twenty
four periods, and we measured you know, air pollution PM
two point five levels in the bedroom CO two levels, temperature, humidity,
(13:43):
and noise and lo and behold, we get significant effects
on sleep of air pollution, CO two, temperature, and noise,
always in the sense that higher levels are worse for sleep.
So in that sense, I think a lot of the
things that we observe on the ISS translate back nicely
(14:03):
to situations on Earth.
Speaker 4 (14:06):
Matthias's job is to study all the physiological effects of
outer space so we can avoid any surprises on the
adventurers that are heading up there. But dealing with an
environment as new as that, there will always be something unexpected.
I found the challenge regarding noise particularly surprising. My assumption
would have been that up in space that you're probably
(14:29):
dealing with less noise than you are on the ground.
Speaker 5 (14:32):
Well, you know, outside the space station it's incredibly quiet
because you have a vacuum and there's you know, sounds
are not transported at all. But inside the space station
you have you know, lots of pumps and devices and alarms,
so there's a constant background noise level. But there's also
you know, intermittent noise events that can grab your attention
(14:56):
and also affect your sleep.
Speaker 4 (15:00):
Yeah, so how does that kind of noise affect or sleep?
What does it do?
Speaker 2 (15:05):
Well?
Speaker 5 (15:05):
You know, one thing is that our auditory system has
kind of a watchmen function. It's like always online, it's
constantly monitoring our environment for potential threats. So we have
to have some sensory inputs that we're still monitoring while
we're sleeping. And if everything dangerous comes up, you know,
we're woken up and so that we can actually run
(15:26):
away and get away from that threat. So the auditory
system is monitoring the environment while we're sleeping, and not
only for sound levels, but actually for content. There were
studies as early as in the nineteen sixties where they
would playback names, and whenever your own name was played back,
you would wake up with a much higher probability than
when it was just another name that didn't have a
(15:47):
meaning for you. So it's both sound levels and content
that do matter. So in that sense, you know, if
you have an alarm, I mean alarm, alarms actually meant
to grab your attention and to arouse you, like an
alarm clock right or baby crying that those sounds have
properties that make you wake up. So if there's an
alarm on the iss, obviously you know the intent is
(16:09):
to wake you up. But oftentimes there are like alarms
that are not that important that wake you up. Nevertheless,
so there is you know, a pump running every time
there's a change in the noise levels that is very
meaningful to humans and more likely to wake you up.
So this is you know, when it's a noisy on
the International Space Station that may actually affect the astronauts
(16:31):
sleep as well.
Speaker 4 (16:33):
The mechanism in our brains that can determine which noises
are normal and which are important, all while we're basically
shut off has got to be one of evolution's most
useful and coolest achievements, a testament to our species' ability
to explore even places we were explicitly never meant to go.
Speaker 3 (16:52):
The thing that surprised me is how quickly, just how
adaptable the human body is. Like you get up there,
it's one of the weirdest environments. You can suddenly find
yourself and you're floating. You feel weird, you're dizzy. For
the first couple of days, you've got this fluid shift
going on, so you feel like you're standing on your head.
But then after a few days, even the people that
have trouble a little trouble adapting, even they will adapt.
(17:15):
And then you know, surprisingly, even after a short shuttle
mission of one or two weeks, when you come back,
your body's already forgotten what it's like to be on Earth,
and so you've got to adapt to being back on Earth,
where you're dizzy again. You can't walk a straight line,
save your life. You might feel a little nauseous, you
might feel fatigued and low on energy, but after a
few days after shuttle mission, you bounce back pretty well.
(17:37):
So the human body can adapt to these different environments
surprisingly well.
Speaker 4 (17:47):
That's all for this episode. Join me again next week
when we learn about people who live at the top
of the world, where the sun stays in the sky
for months at a time, and how the perpetual daytime
affects their sleeping patterns.
Speaker 1 (18:00):
Winter is so much easier just because it's stock all
the time. But in the summer we have to like
just close all the windows, all the cuns, put like
codboard on to block out the light. At like ten pm,
just run around the house play operation nighttime.
Speaker 4 (18:16):
We want to hear from you. Leave a rating a
review for our show on your podcast player of choice.
You can find me on Twitter at Anahad O'Connor. Until
next time, hoping you're living your best while sleeping your best.
Chasing Sleep is a production of iHeartRadio in partnership with
Mattress Firm. Our executive producer is Molly Sosha, Our EP
(18:38):
of post is James Foster. Our supervising producer is Keia Swinton.
Our producer is Sierra Kaiser. Our researcher and writer is
Eric Leijia. This show is hosted by me Anahad O'Connor
Three two.
Speaker 2 (00:06):
Space flight definitely changed me.
Speaker 3 (00:07):
I think it has definitely has an effect on everyone
who goes up there, even for a short mission. So,
you know, just looking down at the Earth, I mean,
it's just so beautiful and colorful and looks extremely peaceful.
Speaker 2 (00:19):
Right you're.
Speaker 3 (00:24):
Eighty million kid two point eight.
Speaker 4 (00:27):
Very few people have viewed Earth the way Leroy Choo has,
from over four hundred kilometers above the planet's surface and
cruising at an unimaginable seventeen thousand miles per hour. Leroy
is a chemical engineer and a former NASA astronaut who's
been to outer space on four separate missions, racking up
(00:48):
two hundred and twenty nine days in space.
Speaker 3 (00:52):
One of the things that a lot of people find weird,
and I found a little weird too, is you're not
sure what to do with your head and your neck.
You know, because you're on Earth you're used to feeling
that pressure on your head against a pillow, and in space,
of course, you're just kind of I mean, we actually
do have like a little foam block at the top
of the sleeping bag that you can act as a pillow,
and there's a cloth a fabric strap with velcro that
(01:14):
you can strap against your forehead if you need that
pressure against the back of your head to fall asleep,
and I don't think anyone really uses that.
Speaker 4 (01:21):
Spending that much time in orbit means that Leroy and
his fellow astronauts will definitely see the effects of that
environment on their bodies, particularly when they're trying to sleep,
which is even more of a challenge in space than
it is on Earth. The lack of gravity effects astronauts spines,
their brains, and even the amount of fluid build up
in their nasal cavities, just to name a few of
(01:43):
the challenges. All of these things just make it even
more difficult to get good rest on the final frontier.
Speaker 3 (01:50):
Sleep is not only important when you're really young, but
it's important as a lifestyle, even as a professional to
make sure you get enough sleep so that your brain
can develop to its full capacity. And certainly, anyone in
any position where you have to perform, you know that
you performed best obviously when you've had good sleep and
good rest. So sleep is definitely an important thing, and
(02:12):
it is a challenge in space.
Speaker 4 (02:15):
Beyond the expected challenges of sleeping in space, Leroy experienced
a sort of jet lag as he first embarked.
Speaker 3 (02:23):
So we kept the laboratory running twenty four hours a day,
and so that meant that four hours after launching into
space for my first time, I had to go to sleep.
And so imagine being so excited to be in space
for the first time, looking at the air floating. You know,
we're in this weird environment. Feeling a little weird because
you know you're floating and you're in space, and there
are all these physiological changes happening in your body.
Speaker 4 (02:44):
Anyway, the biology and functions of the human body have
been shaped in part by its evolution in the gravity
of Earth. So how does an astronaut's body, having escaped
that gravity, adapt to life in a spacecraft speeding through
the vacuum of space. Today we're going to explore what
(03:05):
it's like getting rest for our bodies in the ultra
hostile environment of outer space, and how the absence of
gravity and abundance of radiation affect the delicate mechanisms that
allow our bodies and our brains to power down and recharge.
On this episode of Chasing Sleep, Sleep, the Final Frontier. Hi,
(03:32):
I'm Anahad O'Connor, and this is Chasing Sleep and iHeartRadio
production and partnership with Mattress Firm.
Speaker 3 (03:47):
Sleep in space is pretty weird, you know, especially the
first time to get up there. Once we launched into space,
I have to say we were kind of pretty worn
out by the time we did fly. And that's kind
of a joke among us, or not especially those of
us who fly on the Space station, which is not
really a joke. It's like, you know, you're ready to
go fly when you're completely exhausted, and so, you know,
(04:10):
not necessarily the best way to launch into space.
Speaker 4 (04:12):
Right, So you're high above the Earth's atmosphere in space,
a million things going through your mind and all sorts
of different environmental effects happening to your body. What exactly
is it like to sleep up there?
Speaker 3 (04:26):
We had sleep stations on that flight because we were
two shift operations, which meant we had kind of little,
you know, little closets, if you will, hate to use
this word, but they were kind of like little coffins
that we could get into and slide the door shut
so it would be dark, and put ear plugs in.
Speaker 4 (04:44):
Leroy continued to tell the story of his first time
sleeping in space, getting to the obstacle that I find
most interesting zero gravity.
Speaker 3 (04:52):
And so I got into my little bunk after I'd
taken my sleeping pills, and it was dark and had
my ear plugs in, and I knew the orientation of
the Space Shuttle. Usually it was always the belly of
the shuttle facing the Earth, so I knew the orientation
of the shuttle. I knew my orientation inside of that
dark sleep station, and I was laying on my back.
Although I was floating, I wasn't really laying. I was
(05:14):
just floating in there in a sleeping bag, and I
kind of felt like laying on my side, and it
didn't make any sense whatsoever. But I rotated ninety degrees,
and in my mind I knew I was on my
side relative to the Earth. Didn't make any difference because
I was floating. And then I fell asleep.
Speaker 4 (05:29):
So just describing these sleep closets seems like an interesting
place to have to squeeze into. For rest, are there
multiple astronauts in each bunk? And exactly how tight is
the space on a bed up there in space?
Speaker 2 (05:44):
It looks like a big box.
Speaker 3 (05:46):
Okay, So you slide the door open and you kind
of get yourself inside, and then there's three other people
beneath you if you're on the top right, but you're
all separate.
Speaker 2 (05:53):
You're on your own little box.
Speaker 3 (05:55):
And there's airflow, so you got plenty of ventilation, so
you don't, you know, build up carbon dox and all that.
But the sleeping bag's in there, and it's just kind
of floating in there. There's not much room. There's room
for nothing else except you, basically. So one part about
being an astronaut you can't be the slightest bit claustrophobic,
and that doesn't work out.
Speaker 2 (06:14):
But it's not that bad. It's not uncomfortable.
Speaker 4 (06:17):
Maybe it's not uncomfortable, but there's a reason it takes
months of training just to get used to sleeping in
those quarters. And beyond the training, Leroy explained how extensively
he and his fellow astronauts were monitored for sleep and
for other medical conditions.
Speaker 3 (06:31):
So, for example, on that same first mission, I had
to wear an actigraph during my sleep period. It was
a little thing I had to put on my wrist
and it was just monitor. It was trying to get
a handle on how well I was sleeping, how restless
I was, how long it took for me to stop
moving around and go to sleep, and then during sleep
how much I moved around? So they were collecting data
like that. There are also journals that you that you
(06:54):
could keep on your part of that was your sleep quality?
How was your sleep quality? Anecdotally for myself, it seems
like I need a little less sleep in space.
Speaker 2 (07:04):
I don't know why.
Speaker 3 (07:05):
It just seems like maybe I need about an hour
less in space, or I would wake up maybe an
hour earlier than I might hear on the Earth and
sleep was okay.
Speaker 4 (07:14):
The struggle to get good sleep and outer space may
not be easy, but Leroy told me about plenty of
moments that made all the hard work well worth it.
Speaker 2 (07:23):
Yeah.
Speaker 3 (07:23):
I think the most wow moment of my space flights
was on my third flight. We were on the second
major assembly mission of the Space station program, and during
that time I was doing a spacewalk, one of the spacewalks,
and my boots were attached to the robotic arm of
the Space Shuttle and I was being moved from one
work site to another, and during that transition of several minutes,
(07:45):
during a good part of it, I was face down
towards the Earth and I couldn't see the space station
or the space shuttle out of my peripheral vision, and
so I was looking straight down at the Earth, watching
the clouds and the continents roll by, and I felt
like a satellite flying over the Earth was probably the
most amazing, you know, few minutes of my career.
Speaker 4 (08:07):
We'll be right back after a brief message from our
partners at Mattress Firm, and now back to chasing sleep.
The moment the human body enters space, a place we've
definitely not evolved to be, our bodies inner mechanisms start
(08:28):
to change.
Speaker 3 (08:30):
We evolved here on Earth, so life generally likes where
it evolved, and so humans there are a number of
biomedical things that happened to us in space, and none
of them are good. A lot of people have a
little bit of congestion because in space there's a fluid
shift where you're no longer have gravity pulling fluids down
into your legs, so you have a fluid shift, and
(08:50):
even though your body tries to equilibrate that, in fact,
the average person loses about two liters of water in space.
You know, you carry about two leaders less water in
space when you're floating around, So imagine one of those
big soda bottles. That's how much less water is in
the average person. But nonetheless you still feel a little
bit full headed, a little bit like you're laying on
(09:10):
an inclined head down, and so that can make you
feel a little bit congested. And so, you know, that
was something I was aware of during my sleep, is
that I couldn't breathe as easily through my nose, you know,
and sometimes that would wake me up or something.
Speaker 4 (09:27):
Leroy has amazing firsthand insight into the challenges that astronauts
face and the techniques to overcome them. So to better
understand the technicalities behind how space is affecting our bodies
and brains, I sat down with doctor Mattias Bosner, a
professor of psychiatry.
Speaker 5 (09:44):
I joined the German Aerospace Center actually the Flight Physiology division,
and was actually hired to investigate the effects of aircraft
noise on sleep. Was the largest study ever that was
done at the time at the German Aerospace Center. Stayed
at the German Aerospace Center for te years, studied a
lot of sleep, then came to the United States and
(10:04):
did a lot of work in spaceflight and in astronauts.
Speaker 4 (10:08):
Doctor Mattias Bosner broke down exactly what's going on in
and around the bodies of astronauts that makes it so
hard for them to sleep.
Speaker 5 (10:17):
We also see some volume shifts in the brain and
the volumes that carry the cerebrospinal fluid they actually extend
doing long duration spaceflight. And then there's the radiation, which
is not a super big deal on the ISS because
it's still in a low Earth orbit and it's within
earth magnetic shield. But once we venture out of our
(10:39):
lower Earth orbit, you know, back to the Moon or
to Mars, radiation becomes a major issue. And we actually
generated predictive models for NASA looking at all the different
environmental stressors on the ISS, and radiation was one that
was consistently showing up and that it was affecting cognitive performance. Oh,
(11:00):
they're still you know, in that protective environment magnetically, but
then there's also the nutrition is different. On the ISS.
You have oftentimes elevated carbon dioxide levels that can affect performance.
Sometimes you know, lower oxygen levels. You have just the
psychological stress related to living in an isolated, confined, and
(11:24):
extreme environment with a threat to life component.
Speaker 4 (11:29):
These changes on your body can be very jarring. For
first time astronauts. But with enough time, incredibly the human
body begins to adapt, including changes to how our brain functions.
Speaker 5 (11:42):
There is a lot of adaptation going on, both physiologically
but also from a brain perspective, because you know that
gravity vector is gone, and you know your brain kind
of has to rewire itself or reweight the different neural
connections to make sense of this.
Speaker 2 (12:01):
You know, for example, the visual.
Speaker 5 (12:03):
Input becomes much more important now because you know, our
vestibular system that tells us how we are oriented in
space is no longer working. Basically it's switched off, right,
So there's a lot of brain plascicity going on. But
also you know, because of that, nausea is a big
problem during the first you know, one or two weeks,
(12:23):
and you know there's a medication for that as well.
Or back pain is another big issue. You know, astronauts
spines are actually extending because you know, we don't have
that gravity vector, and you know the spine is not
compressed when we're walking around.
Speaker 4 (12:39):
It's pretty interesting how studying something that might seem as
foreign as an astronaut sleeping in space gives us great
insight into how our bodies work down here on Earth.
I asked Mattias what other info he was able to
discover for US earthlings while studying the sleep of astronauts.
Speaker 5 (12:57):
We did this study in twenty four astronauts measured their
perform moments and we asked them questions about their sleep
and how they felt, etc. But at the time we
didn't have the environmental data from the International Space Station.
It was actually very interesting to see which variables were,
you know, showing up. And I already mentioned the radiation
that's not that relevant on Earth, but CO two, for example,
(13:19):
is one of the factors that plays a role. And
we just did another study here on Earth in bedroom
of participants who were wearing like an actigraph which is
a fitbit like device, for fourteen consecutive nights or twenty
four periods, and we measured you know, air pollution PM
two point five levels in the bedroom CO two levels, temperature, humidity,
(13:43):
and noise and lo and behold, we get significant effects
on sleep of air pollution, CO two, temperature, and noise,
always in the sense that higher levels are worse for sleep.
So in that sense, I think a lot of the
things that we observe on the ISS translate back nicely
(14:03):
to situations on Earth.
Speaker 4 (14:06):
Matthias's job is to study all the physiological effects of
outer space so we can avoid any surprises on the
adventurers that are heading up there. But dealing with an
environment as new as that, there will always be something unexpected.
I found the challenge regarding noise particularly surprising. My assumption
would have been that up in space that you're probably
(14:29):
dealing with less noise than you are on the ground.
Speaker 5 (14:32):
Well, you know, outside the space station it's incredibly quiet
because you have a vacuum and there's you know, sounds
are not transported at all. But inside the space station
you have you know, lots of pumps and devices and alarms,
so there's a constant background noise level. But there's also
you know, intermittent noise events that can grab your attention
(14:56):
and also affect your sleep.
Speaker 4 (15:00):
Yeah, so how does that kind of noise affect or sleep?
What does it do?
Speaker 2 (15:05):
Well?
Speaker 5 (15:05):
You know, one thing is that our auditory system has
kind of a watchmen function. It's like always online, it's
constantly monitoring our environment for potential threats. So we have
to have some sensory inputs that we're still monitoring while
we're sleeping. And if everything dangerous comes up, you know,
we're woken up and so that we can actually run
(15:26):
away and get away from that threat. So the auditory
system is monitoring the environment while we're sleeping, and not
only for sound levels, but actually for content. There were
studies as early as in the nineteen sixties where they
would playback names, and whenever your own name was played back,
you would wake up with a much higher probability than
when it was just another name that didn't have a
(15:47):
meaning for you. So it's both sound levels and content
that do matter. So in that sense, you know, if
you have an alarm, I mean alarm, alarms actually meant
to grab your attention and to arouse you, like an
alarm clock right or baby crying that those sounds have
properties that make you wake up. So if there's an
alarm on the iss, obviously you know the intent is
(16:09):
to wake you up. But oftentimes there are like alarms
that are not that important that wake you up. Nevertheless,
so there is you know, a pump running every time
there's a change in the noise levels that is very
meaningful to humans and more likely to wake you up.
So this is you know, when it's a noisy on
the International Space Station that may actually affect the astronauts
(16:31):
sleep as well.
Speaker 4 (16:33):
The mechanism in our brains that can determine which noises
are normal and which are important, all while we're basically
shut off has got to be one of evolution's most
useful and coolest achievements, a testament to our species' ability
to explore even places we were explicitly never meant to go.
Speaker 3 (16:52):
The thing that surprised me is how quickly, just how
adaptable the human body is. Like you get up there,
it's one of the weirdest environments. You can suddenly find
yourself and you're floating. You feel weird, you're dizzy. For
the first couple of days, you've got this fluid shift
going on, so you feel like you're standing on your head.
But then after a few days, even the people that
have trouble a little trouble adapting, even they will adapt.
(17:15):
And then you know, surprisingly, even after a short shuttle
mission of one or two weeks, when you come back,
your body's already forgotten what it's like to be on Earth,
and so you've got to adapt to being back on Earth,
where you're dizzy again. You can't walk a straight line,
save your life. You might feel a little nauseous, you
might feel fatigued and low on energy, but after a
few days after shuttle mission, you bounce back pretty well.
(17:37):
So the human body can adapt to these different environments
surprisingly well.
Speaker 4 (17:47):
That's all for this episode. Join me again next week
when we learn about people who live at the top
of the world, where the sun stays in the sky
for months at a time, and how the perpetual daytime
affects their sleeping patterns.
Speaker 1 (18:00):
Winter is so much easier just because it's stock all
the time. But in the summer we have to like
just close all the windows, all the cuns, put like
codboard on to block out the light. At like ten pm,
just run around the house play operation nighttime.
Speaker 4 (18:16):
We want to hear from you. Leave a rating a
review for our show on your podcast player of choice.
You can find me on Twitter at Anahad O'Connor. Until
next time, hoping you're living your best while sleeping your best.
Chasing Sleep is a production of iHeartRadio in partnership with
Mattress Firm. Our executive producer is Molly Sosha, Our EP
(18:38):
of post is James Foster. Our supervising producer is Keia Swinton.
Our producer is Sierra Kaiser. Our researcher and writer is
Eric Leijia. This show is hosted by me Anahad O'Connor
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