[ExI] Life extension via lifestyle - sleep

Dave Sill sparge at gmail.com
Tue May 12 18:57:14 UTC 2020


Here's the transcript for those prefer to read.


Thank you very much. Well, I would like to start with testicles.


Men who sleep five hours a night have significantly smaller testicles than
those who sleep seven hours or more.


In addition, men who routinely sleep just four to five hours a night will
have a level of testosterone which is that of someone 10 years their
senior. So a lack of sleep will age a man by a decade in terms of that
critical aspect of wellness. And we see equivalent impairments in female
reproductive health caused by a lack of sleep.

This is the best news that I have for you today.


>From this point, it may only get worse. Not only will I tell you about the
wonderfully good things that happen when you get sleep, but the alarmingly
bad things that happen when you don't get enough, both for your brain and
for your body.

Let me start with the brain and the functions of learning and memory,
because what we've discovered over the past 10 or so years is that you need
sleep after learning to essentially hit the save button on those new
memories so that you don't forget. But recently, we discovered that you
also need sleep before learning to actually prepare your brain, almost like
a dry sponge ready to initially soak up new information. And without sleep,
the memory circuits of the brain essentially become waterlogged, as it
were, and you can't absorb new memories.

So let me show you the data. Here in this study, we decided to test the
hypothesis that pulling the all-nighter was a good idea. So we took a group
of individuals and we assigned them to one of two experimental groups: a
sleep group and a sleep deprivation group. Now the sleep group, they're
going to get a full eight hours of slumber, but the deprivation group,
we're going to keep them awake in the laboratory, under full supervision.
There's no naps or caffeine, by the way, so it's miserable for everyone
involved. And then the next day, we're going to place those participants
inside an MRI scanner and we're going to have them try and learn a whole
list of new facts as we're taking snapshots of brain activity. And then
we're going to test them to see how effective that learning has been. And
that's what you're looking at here on the vertical axis. And when you put
those two groups head to head, what you find is a quite significant,
40-percent deficit in the ability of the brain to make new memories without

I think this should be concerning, considering what we know is happening to
sleep in our education populations right now. In fact, to put that in
context, it would be the difference in a child acing an exam versus failing
it miserably -- 40 percent. And we've gone on to discover what goes wrong
within your brain to produce these types of learning disabilities. And
there's a structure that sits on the left and the right side of your brain,
called the hippocampus. And you can think of the hippocampus almost like
the informational inbox of your brain. It's very good at receiving new
memory files and then holding on to them. And when you look at this
structure in those people who'd had a full night of sleep, we saw lots of
healthy learning-related activity. Yet in those people who were
sleep-deprived, we actually couldn't find any significant signal
whatsoever. So it's almost as though sleep deprivation had shut down your
memory inbox, and any new incoming files -- they were just being bounced.
You couldn't effectively commit new experiences to memory.

So that's the bad that can happen if I were to take sleep away from you,
but let me just come back to that control group for a second. Do you
remember those folks that got a full eight hours of sleep? Well, we can ask
a very different question: What is it about the physiological quality of
your sleep when you do get it that restores and enhances your memory and
learning ability each and every day? And by placing electrodes all over the
head, what we've discovered is that there are big, powerful brainwaves that
happen during the very deepest stages of sleep that have riding on top of
them these spectacular bursts of electrical activity that we call sleep
spindles. And it's the combined quality of these deep-sleep brainwaves that
acts like a file-transfer mechanism at night, shifting memories from a
short-term vulnerable reservoir to a more permanent long-term storage site
within the brain, and therefore protecting them, making them safe. And it
is important that we understand what during sleep actually transacts these
memory benefits, because there are real medical and societal implications.

And let me just tell you about one area that we've moved this work out
into, clinically, which is the context of aging and dementia. Because it's
of course no secret that, as we get older, our learning and memory
abilities begin to fade and decline. But what we've also discovered is that
a physiological signature of aging is that your sleep gets worse,
especially that deep quality of sleep that I was just discussing. And only
last year, we finally published evidence that these two things, they're not
simply co-occurring, they are significantly interrelated. And it suggests
that the disruption of deep sleep is an underappreciated factor that is
contributing to cognitive decline or memory decline in aging, and most
recently we've discovered, in Alzheimer's disease as well.

Now, I know this is remarkably depressing news. It's in the mail. It's
coming at you. But there's a potential silver lining here. Unlike many of
the other factors that we know are associated with aging, for example
changes in the physical structure of the brain, that's fiendishly difficult
to treat. But that sleep is a missing piece in the explanatory puzzle of
aging and Alzheimer's is exciting because we may be able to do something
about it.

And one way that we are approaching this at my sleep center is not by using
sleeping pills, by the way. Unfortunately, they are blunt instruments that
do not produce naturalistic sleep. Instead, we're actually developing a
method based on this. It's called direct current brain stimulation. You
insert a small amount of voltage into the brain, so small you typically
don't feel it, but it has a measurable impact. Now if you apply this
stimulation during sleep in young, healthy adults, as if you're sort of
singing in time with those deep-sleep brainwaves, not only can you amplify
the size of those deep-sleep brainwaves, but in doing so, we can almost
double the amount of memory benefit that you get from sleep. The question
now is whether we can translate this same affordable, potentially portable
piece of technology into older adults and those with dementia. Can we
restore back some healthy quality of deep sleep, and in doing so, can we
salvage aspects of their learning and memory function? That is my real hope
now. That's one of our moon-shot goals, as it were.

So that's an example of sleep for your brain, but sleep is just as
essential for your body. We've already spoken about sleep loss and your
reproductive system. Or I could tell you about sleep loss and your
cardiovascular system, and that all it takes is one hour. Because there is
a global experiment performed on 1.6 billion people across 70 countries
twice a year, and it's called daylight saving time. Now, in the spring,
when we lose one hour of sleep, we see a subsequent 24-percent increase in
heart attacks that following day. In the autumn, when we gain an hour of
sleep, we see a 21-percent reduction in heart attacks. Isn't that
incredible? And you see exactly the same profile for car crashes, road
traffic accidents, even suicide rates.

But as a deeper dive, I want to focus on this: sleep loss and your immune
system. And here, I'll introduce these delightful blue elements in the
image. They are called natural killer cells, and you can think of natural
killer cells almost like the secret service agents of your immune system.
They are very good at identifying dangerous, unwanted elements and
eliminating them. In fact, what they're doing here is destroying a
cancerous tumor mass. So what you wish for is a virile set of these immune
assassins at all times, and tragically, that's what you don't have if
you're not sleeping enough.

So here in this experiment, you're not going to have your sleep deprived
for an entire night, you're simply going to have your sleep restricted to
four hours for one single night, and then we're going to look to see what's
the percent reduction in immune cell activity that you suffer. And it's not
small -- it's not 10 percent, it's not 20 percent. There was a 70-percent
drop in natural killer cell activity. That's a concerning state of immune
deficiency, and you can perhaps understand why we're now finding
significant links between short sleep duration and your risk for the
development of numerous forms of cancer. Currently, that list includes
cancer of the bowel, cancer of the prostate and cancer of the breast. In
fact, the link between a lack of sleep and cancer is now so strong that the
World Health Organization has classified any form of nighttime shift work
as a probable carcinogen, because of a disruption of your sleep-wake

So you may have heard of that old maxim that you can sleep when you're
dead. Well, I'm being quite serious now -- it is mortally unwise advice. We
know this from epidemiological studies across millions of individuals.
There's a simple truth: the shorter your sleep, the shorter your life.
Short sleep predicts all-cause mortality.

And if increasing your risk for the development of cancer or even
Alzheimer's disease were not sufficiently disquieting, we have since
discovered that a lack of sleep will even erode the very fabric of
biological life itself, your DNA genetic code. So here in this study, they
took a group of healthy adults and they limited them to six hours of sleep
a night for one week, and then they measured the change in their gene
activity profile relative to when those same individuals were getting a
full eight hours of sleep a night. And there were two critical findings.
First, a sizable and significant 711 genes were distorted in their
activity, caused by a lack of sleep. The second result was that about half
of those genes were actually increased in their activity. The other half
were decreased.

Now those genes that were switched off by a lack of sleep were genes
associated with your immune system, so once again, you can see that immune
deficiency. In contrast, those genes that were actually upregulated or
increased by way of a lack of sleep, were genes associated with the
promotion of tumors, genes associated with long-term chronic inflammation
within the body, and genes associated with stress, and, as a consequence,
cardiovascular disease. There is simply no aspect of your wellness that can
retreat at the sign of sleep deprivation and get away unscathed. It's
rather like a broken water pipe in your home. Sleep loss will leak down
into every nook and cranny of your physiology, even tampering with the very
DNA nucleic alphabet that spells out your daily health narrative.

And at this point, you may be thinking, "Oh my goodness, how do I start to
get better sleep? What are you tips for good sleep?" Well, beyond avoiding
the damaging and harmful impact of alcohol and caffeine on sleep, and if
you're struggling with sleep at night, avoiding naps during the day, I have
two pieces of advice for you.

The first is regularity. Go to bed at the same time, wake up at the same
time, no matter whether it's the weekday or the weekend. Regularity is
king, and it will anchor your sleep and improve the quantity and the
quality of that sleep. The second is keep it cool. Your body needs to drop
its core temperature by about two to three degrees Fahrenheit to initiate
sleep and then to stay asleep, and it's the reason you will always find it
easier to fall asleep in a room that's too cold than too hot. So aim for a
bedroom temperature of around 65 degrees, or about 18 degrees Celsius.
That's going to be optimal for the sleep of most people.

And then finally, in taking a step back, then, what is the mission-critical
statement here? Well, I think it may be this: sleep, unfortunately, is not
an optional lifestyle luxury. Sleep is a nonnegotiable biological
necessity. It is your life-support system, and it is Mother Nature's best
effort yet at immortality. And the decimation of sleep throughout
industrialized nations is having a catastrophic impact on our health, our
wellness, even the safety and the education of our children. It's a silent
sleep loss epidemic, and it's fast becoming one of the greatest public
health challenges that we face in the 21st century.

I believe it is now time for us to reclaim our right to a full night of
sleep, and without embarrassment or that unfortunate stigma of laziness.
And in doing so, we can be reunited with the most powerful elixir of life,
the Swiss Army knife of health, as it were.

And with that soapbox rant over, I will simply say, good night, good luck,
and above all ... I do hope you sleep well.

Thank you very much indeed.


Thank you.


Thank you so much.

David Biello: No, no, no. Stay there for a second. Good job not running
away, though. I appreciate that. So that was terrifying.

Matt Walker: You're welcome. DB: Yes, thank you, thank you. Since we can't
catch up on sleep, what are we supposed to do? What do we do when we're,
like, tossing and turning in bed late at night or doing shift work or
whatever else?

MW: So you're right, we can't catch up on sleep. Sleep is not like the
bank. You can't accumulate a debt and then hope to pay it off at a later
point in time. I should also note the reason that it's so catastrophic and
that our health deteriorates so quickly, first, it's because human beings
are the only species that deliberately deprive themselves of sleep for no
apparent reason.

DB: Because we're smart.

MW: And I make that point because it means that Mother Nature, throughout
the course of evolution, has never had to face the challenge of this thing
called sleep deprivation. So she's never developed a safety net, and that's
why when you undersleep, things just sort of implode so quickly, both
within the brain and the body. So you just have to prioritize.

DB: OK, but tossing and turning in bed, what do I do?

MW: So if you are staying in bed awake for too long, you should get out of
bed and go to a different room and do something different. The reason is
because your brain will very quickly associate your bedroom with the place
of wakefulness, and you need to break that association. So only return to
bed when you are sleepy, and that way you will relearn the association that
you once had, which is your bed is the place of sleep. So the analogy would
be, you'd never sit at the dinner table, waiting to get hungry, so why
would you lie in bed, waiting to get sleepy?

DB: Well, thank you for that wake-up call. Great job, Matt.

MW: You're very welcome. Thank you very much.
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