The brain benefits of deep sleep -- and how to get more of it | Dan Gartenberg

What if you could make your sleep more efficient?

As a sleep scientist,

this is the question that has captivated me

for the past 10 years.

Because while the lightbulb and technology have brought about a world

of 24-hour work and productivity,

it has come at the cost

of our naturally occurring circadian rhythm

and our body's need for sleep.

The circadian rhythm dictates our energy level throughout the day,

and only recently we've been conducting a global experiment on this rhythm,

which is putting our sleep health

and ultimately our life quality in jeopardy.

Because of this,

we aren't getting the sleep we need,

with the average American sleeping a whole hour less

than they did in the 1940s.

For some reason,

we decided to wear it as a badge of honor

that we can get by on not enough sleep.

This all adds up to a real health crisis.

Most of us know that poor sleep is linked to diseases

like Alzheimer's, cardiovascular disease,

stroke and diabetes.

And if you go untreated with a sleep disorder like sleep apnea,

you're more likely to get many of these illnesses.

But did you know about sleep's impact on your mental states?

Poor sleep makes us make risky, rash decisions

and is a drain on our capacity for empathy.

When sleep deprivation literally makes us more sensitive to our own pain,

it's not so surprising that we have a hard time relating to others

and just generally being a good and healthy person

when we're sleep-deprived.

Scientists are now starting to understand

how not only the quantity

but also the quality of sleep impacts our health and well-being.

My research focuses

on what many scientists believe is the most regenerative stage of sleep:

deep sleep.

We now know that generally speaking,

there are three stages of sleep:

light sleep,

rapid eye movement or REM

and deep sleep.

We measure these stages by connecting electrodes to the scalp, chin and chest.

In light sleep and REM,

our brain waves are very similar to our brain waves in waking life.

But our brain waves in deep sleep have these long-burst brain waves

that are very different from our waking life brain waves.

These long-burst brain waves are called delta waves.

When we don't get the deep sleep we need,

it inhibits our ability to learn

and for our cells and bodies to recover.

Deep sleep is how we convert all those interactions

that we make during the day

into our long-term memory and personalities.

As we get older,

we're more likely to lose these regenerative delta waves.

So in way, deep sleep and delta waves

are actually a marker for biological youth.

So naturally, I wanted to get more deep sleep for myself

and I literally tried almost every gadget, gizmo, device and hack out there --

consumer-grade, clinical-grade,

what have you.

I learned a lot, and I found I really do need, like most people,

eight hours of sleep.

I even shifted my circadian component

by changing my meals, exercise and light exposure,

but I still couldn't find a way to get a deeper night of sleep ...

that is until I met Dr. Dmitry Gerashchenko

from Harvard Medical School.

Dmitry told me about a new finding in the literature,

where a lab out of Germany showed that if you could play certain sounds

at the right time in people's sleep,

you could actually make sleep deeper and more efficient.

And what's more, is that this lab showed

that you actually could improve next-day memory performance

with this sound.

Dmitry and I teamed up,

and we began working on a way to build this technology.

With our research lab collaborators at Penn State,

we designed experiments in order to validate our system.

And we've since received grant funding from the National Science Foundation

and the National Institute of Health

to develop this deep-sleep stimulating technology.

Here's how it works.

People came into the lab

and we hooked them up to a number of devices,

two of which I have on right here --

not a fashion statement.

(Laughter)

When we detected that people were in deep sleep,

we played the deep-sleep stimulating sounds

that were shown to make them have deeper sleep.

I'm going to demo this sound for you right now.

(Repeating sound waves)

Pretty weird, right?

(Laughter)

So that sound is actually at the same burst frequency as your brain waves

when your brain is in deep sleep.

That sound pattern actually primes your mind

to have more of these regenerative delta waves.

When we asked participants the next day about the sounds,

they were completely unaware that we played the sounds,

yet their brains responded with more of these delta waves.

Here's an image of someone's brain waves from the study that we conducted.

See the bottom panel?

This shows the sound being played at that burst frequency.

Now look at the brain waves in the upper part of the graph.

You can see from the graph

that the sound is actually producing more of these regenerative delta waves.

We learned that we could accurately track sleep

without hooking people up to electrodes

and make people sleep deeper.

We're continuing to develop

the right sound environment and sleep habitat

to improve people's sleep health.

Our sleep isn't as regenerative as it could be,

but maybe one day soon,

we could wear a small device

and get more out of our sleep.

Thank you.

(Applause)