Hi, I’m Blake Jones,
I’m an Assistant Professor in Human Development
and Family Studies at Purdue University and I’m gonna be talking today
a little bit about the connection between
sleep and obesity. And we know that, of course, obesity has- we’ve seen rapid increases
in obesity over the past 30 years. It slowed down a little bit
as far as how it’s growing, but, uh, it’s about tripled
in rates for child obesity in the past 30 years,
and a lot of people don’t necessarily understand
the connection with sleep and obesity
and so today I’m gonna talk
a little bit about some of the-the possible ways that these are connected. Um, with sleep it’s really
important to recognize that sleep is something that, uh, there’s-there’s quite
a large problem in our country with sleep issues
and different reports and talking to pediatricians have suggested that anywhere between 20 and 40%
of young kids have been reported
to have sleep issues, and what’s concerning about this is that it’s not necessarily just that that many kids
have sleep issues but a lot of parents would
never report something like insufficient sleep
to be an issue. Um, a lot of parents are not
aware of how many sleep hours that a child should get,
especially at younger ages, and so it’s pretty
consistent in our, um, different studies that we see
parents will report, “Oh, my child is getting
eight or nine hours of sleep every night. They’re doing a great job.” And we look at this and we see that these are, you know,
2 and 3 and 4-year-old kids and the parents are proud
of the amount of sleep that they’re getting,
not realizing that the National Sleep Foundation and others have suggested that kids that age
are getting a minimum of 11 hours of sleep a night, so it should be more
in the range of 11 to 13 hours and these parents are proud
that their kids get their-their full 8 hours
a night, right? So, this is a big drop
in what they should be getting and this is concerning. Um, we’ve also seen that
with adults there’s been a large drop in sleep
over the past 30 or 40 years. In fact, some studies have
shown that in the last 40 years adults have lost about
an hour or two a night of sleep on average. Um, another thing that they
looked at was how many adults are getting less than
seven hours of sleep, and they’ve shown that that
amount has gone from 15% of adults up to 39%, so, almost half of adults
are getting less than seven hours
of sleep a night. Again, this is concerning for
a lot of different reasons. We know that sleep has
a lot of restorative properties. It helps our brain
to function better. It helps our bodies
to function better. It gives us time to recover
from injuries and inflammation and all kinds of things that
allows some of our systems in our body to rest while others
speed up their processes such as metabolism
and other functions of healing that can happen during sleep. So sleep is
a very powerful thing that we should spend about
a third of our lives doing and yet if you’re
anything like me, sometimes when we-
when push comes to shove and we have demands on our time the first thing that we do is
we let go of sleep because that’s something
that other people don’t see. We kind of think of that
as maybe a private issue that we do on our own
that we can adjust and that we’ll catch up later. And the problem is,
we don’t tend to catch up and we don’t know that catching up really works very well. In fact, there’s studies that
have shown that catching up doesn’t work very well
over-overall and you can only catch up
for a certain amount of time. So if you get several days
behind on your sleep then it’s as-as good as lost and you can’t really make up
for that time. And so we get
into these patterns because of our busy schedules where adults are sleeping less. Maybe you’re working longer
hours than you used to, maybe you have
more time demands, but this also rubs off
on our kids and so we have issues where kids are not getting enough sleep because of family routines. And so if you think
about it for a second, a lot of my research
I-I talk to parents, I talk to kids and we interview them trying to find out what some of the predictors
of obesity are. And when you talk to parents
one of the big challenges they have is just building
those family routines that are consistent,
and so you see things like, you know, my-my spouse and I we both come home
at the same time, um, and it’s late,
the kids are already hungry and so we rush through dinner then we have to try and hurry and get the kids ready for bed. We have to hurry and help
them with their homework. The next thing you know
it’s 9 or 10 or 11 o’clock and we’re all finally
getting to sleep. But just because you’re behind
on your sleep schedules at night doesn’t mean that you
can sleep in in the morning, right, and so work demands,
school times, all those things stay the same regardless of how pressured
you are at night. And so when we take on
extra things like the kids’ soccer games
or extra activities or whatever we’re doing, all of those things tend
to push back bedtimes, and research
has been very clear that when you push back bedtimes certain things tend to increase such as the amount
of TV you view, um, you sleep a little bit less, not a whole lot less,
but even with less, even with later bedtimes, uh,
even if you’re getting the same amount of sleep
we’ve shown that there are some
pretty negative consequences. So if you control for
the total time sleeping, those that go to bed later still have
some negative outcomes. And so it’s not just
the amount of sleep, we’re also concerned with kind of those-those routines
in general. What time you go to bed, what
your consistent routines are versus people that
kind of bounce around, and that-that’s a really
serious concern for people that don’t have consistent
schedules, and so, uh, that’s-that’s something that
we need to be aware of. And there’s a couple
of different thoughts about why sleep and obesity
might be related, and so I wanna talk just for
a second about some specific research examples
that have come out. In-in the last couple of years
we’ve seen things like, uh, there was a study by Dev et. al.
just last year and they looked at 22
different predictors of obesity, and these are all things that
have been shown in other studies to be significant
predictors of obesity. What they found is
that out of those 22, insufficient sleep
was the top predictor of child obesity. It was even higher
than parent BMI, which, uh, surprised a lot of people,
and it was higher than a lot of other factors,
even when you control for things like parent education
and family income and some other issues
that we know are related to both sleep and obesity. It tends to be that, um,
especially children in impoverished areas,
there are some different racial and minority differences
where certain kids are more predisposed
to get less sleep or to have worse,
uh, obesity outcomes, and we’ve seen
these things are connected. But even when you
control for those, we still see that sleep
and obesity are related and that’s concerning. And so I wanna talk
just for a second about a couple
of different possible links between sleep and obesity
that are concerning. The first angle
that we can look at when you talk about
sleep and obesity is does one cause the other,
or is it the other way, right, and so we can look and see
does sleep cause obesity to increase
or is that obesity is causing your sleep quantity
or quality to go down? And so if we look at
that angle for a second we know that as you
increase your body weight it starts to do some things
to your sleep. First of all,
it makes breathing a little bit more difficult. Your-your body fat
starts to increase, lung volume decreases
and some of these issues can significantly affect
the-the quality of sleep. So even if you’re going
to bed and you’re in bed for the eight hours or nine hours
or whatever you plan, the quality of your sleep is
gonna go down somewhat for a lot of people if you’re obese because it starts to affect your throat,
it starts to affect your chest. This pressure increases your
breathing having difficulties. And what happens is your sleep
quality will start to go down. You see things like sleep apnea
will start to occur more often, and with this insufficient sleep or-or lack of quality in sleep, you might be in bed for eight hours but not really get the ben-the benefits of being in bed for that long. And so you see people that
are just constantly tired and a lot of it is not because
they’re not trying to get a consistent sleep routine,
but more so because their body just isn’t able to get
the quality of sleep that they need because their weight
is interfering with that. Again, a lot of this
is through breathing, but it can be through
other things as well such as inflammation and pain. It might be a little bit more
uncomfortable on your joints, on your back. It’s harder to fall asleep
or it’s harder to stay asleep once you’re there. And so these are-these are
concerning things that we think that there might
be some relationship between, um, the amount
of-of sleep you’re getting just based off
of your weight alone. So it’s kind of a,
more of a bi-directional cycle where they both affect
each other. Um, going from the other angle, if you look at how sleep
affects obesity, it seems that there’s
a lot more potential there. Um, if I had to pick one
or the other I would- I would say that that’s probably the more concerning issue for a lot of people because that seems to come first
for a lot of people. What happens is they start
getting busy with things, their sleep goes down,
and this can happen again from the time of
a young child on up, so your sleep starts to go down and your body goes into
a-a different kind of cycle. So the-the thought here is
that as your sleep decreases you become energy deprived. So your body is used to using
a certain amount of energy, it needs so much
restorative time of healing and-and decreasing inflammation and letting you do
your metabolism like you normally
would during sleep, but if you’re not
getting enough sleep, your body starts to
kick in a stress response, and it might not
feel like stress. It might not be something
that you think, um, on a regular basis, yeah,
I really feel stressed today because I didn’t sleep
enough last night but inside your body
this is going on, in your organs
and in your cellular, uh, even at the
cellular level. And so there-there’s some
specific things that we think might be connected in kids, that we’ve seen some patterns
in adults. So one is called the HPA axis,
and this is the hypothalamus, pituitary gland
and adrenal gland. So what happens is as your body starts to feel stressed, your hypothalamus sends a signal to your pituitary gland which then goes
to your adrenal glands just above your kidneys and it says, okay, I’m
stressed, I need more energy, I’m-I’m energy deprived because I didn’t get enough sleep. And so as that-as that
cortisol is released from your adrenal glands
it does a few things that are really negative on your body
if it stays like that. For one it increases
your blood sugar and so you have things like diabetes starting to increase because people’s
blood sugar stays high. Um, some other ones that
happen is you start to get more, um, responses of ghrelin
which is a hormone in your metabolism that tells your body that you’re hungry. Again, because
you’re energy deprived, your body is gonna look for the quickest, easiest
source of energy it can get and so usually that involves
eating fatty or sugary foods because those can be broken down and turned into energy
pretty fast. And so you’ll start to feel
hungry a lot more often. Another thing is that
at the same time your leptin levels go down, and leptin is a-a hormone
in your metabolism that helps your body to
recognize when you’re full. So not only are not
recognizing being full or having these satiety cues you’re also feeling hunger
a lot more often, and so through this process
it can affect your eating. And they’ve shown this
pretty consistently in studies that when you’re sleep deprived you tend to eat more calories. So that’s one avenue that we
think might have something to do with obesity is that
it puts your body in a constant state of stress, even though again it might not be a psychological form of stress that you feel, but internally your body has
recognized this as a stress cue and so it-it tries
to eat certain foods. Another thing it does is it
speeds up your metabolism a little bit, which might
sound like a good thing but this usually
has more to do with breaking down
fats an-and sugars faster which means they get
into your body faster. The problem is,
if you’re sleep deprived, your body’s preparing for this sort of fight-or-flight response, but that’s not really
what you’re doing, you’re just trying to get
through a normal day which might involve
a lot of sitting. And so if you have a sedentary
job and you’re sleep deprived, you’re sitting there all day
waiting to use this energy that your body’s picking up,
and yet you’re not really using
all this energy, and you’re probably tired so you’re a little bit less likely on a lot of-
a lot of circumstances to go and exercise and burn off these extra calories, and so it stores them
as body fat so that it can save them
for another time in case you’re stressed again. But then we sort of get
into this pattern again where, again, we don’t sleep enough
and we continue to build our body fat and it just
continues on and on, um, and then at a certain point,
it makes things like exercise harder, it makes just getting around harder, and it’s a lot more energy
for your body just to maintain the body weight
that you’ve gained, and so you feel like
you wanna eat more just to keep
that body weight going. And so there-there seems
to be some cycles here that are related,
at least in adults, that we’re interested
in finding out if this is what happens
with kids. And so a lot of the work
that I’m doing right now, and I know oth-others
are looking at this as well is we’re tying to-to test
the actual sleep mechanisms and so for a long time,
just like with BMI, we used to just measure BMI
through having people report their height and weight in a lot of these studies, um, we’re recognizing now it’s
much more important to actually measure people;
the same thing with sleep. There’s a lot of new exciting
sleep assessments that go far beyond just asking somebody
how much sleep they got. So for example if I asked you, how much sleep did you get
last night, and you might think
about that for a second and you say,
“Well, I got about seven hours” and I can ask you what time
you went to bed, and that might be
a little bit better id- a better question to ask
is what time did you go to bed and what time did you get up, because sometimes people don’t put those together
quite right. Even if you’re educated, um, you might not add those up right and one of the issues is that you tend to favor yourself in a positive way. And so if I ask you how much
sleep you get on average, and you know that
I might be thinking that sleep is a good thing and you not g-
you’re not getting enough, a lot of people will tend
to over-report the amount of sleep
they’re getting, especially if I ask you how much did you get last night, and you say, “Well, I got
six hours last night, but that’s not normal,” right? We justify it, we say that
there was some other reason why we didn’t get enough sleep. And I’ve had people say
two or three hours when I ask this question
in seminars. It’s pretty common to get
at least somebody in a group that got two or three hours
of sleep, and they always do
the same thing, “Well, but it was a special night because my son was sick or because I had a deadline
on a paper or a job assignment at work.” We always justify that
and the problem is that that happens a lot more often than we really think and so there are better ways
of measuring sleep that will help us
better understand this link between sleep and BMI. Just some new studies
that are starting to look at things like
these-these metabolism hormones in your blood
and trying to see for people that don’t get enough sleep,
is this a chronic problem? Does it-does it constantly
affect your metabolism? Or is this something that kind
of goes through your system an-and comes back at a pretty
quick pace so that you can regulate things again
and reach homeostasis. Um, other studies are looking
at specific types of monitoring sleep. So not just looking at
the amount of time somebody’s in bed,
but the actual sleep quality and doing that
through the-the amount of this- that people move
during their sleep and the amount of, um,
kind of rest that they’re actually getting, not just that you don’t remember because your eyes are closed
and you’re in bed, but we can actually monitor
how restless people are. So we’re looking beyond just sleep qual-or quantity and looking at the quality
of sleep as well. And all of these things
can help us, hopefully, understand a little bit more
about this link between sleep and obesity and also identify
some specific strategies that we can use to build
targeted interventions. This is a really big area
that I think is gonna be needed
in the future. We’re seeing that teenagers
aren’t sleeping enough, um, kids aren’t sleeping enough,
it-it’s just a chronic issue in our society because we have
so many pressures and demands. And again, it’s just
the easiest thing to let go when you have five things pushing in on our time because you think
you can make it up. Uh, there’s also some issues
with circadian rhythms that change for teenagers
and that’s-that’s an issue that teenagers’ bodies
want to be up later and yet we have them
getting up early for school and so they’re not getting enough sleep, and a lot of people don’t know that they should be getting more like nine hours
of sleep a night instead of seven or eight,
and even seven or eight is a lot more than a lot
of teenagers get in these days. So, this is a problem
at-at every age level that we can see right now
and it’s something that is very modifiable. Uh, when you’re looking
at obesity risk, there’s a lot of things
that we can’t do much about. We can’t change somebody’s
family history per se, uh, we can’t necessarily change
their parents’ education or their family income very
easily or the parent BMI, that’s-that can be
really tough to do. But we can do little things
like changing sleep patterns. We can look at that
as a good starting place and I think that’s something that shows a lot of promise for future interventions,
both at the early childhood and at, um, adolescent
and adult levels as well, so that’s something that
I’m excited to be researching and I look forward to the future and seeing what
we can figure out.

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