The Science Of Sleep

[Guest guest]

The below may be of some interest:

The Science Of Sleep

http://www.cbsnews.com/stories/2008/03/14/60minutes/main3939721_page1.

shtml

We don't sleep just to rest our tired bodies? " Stahl asks

, the director of the Sleep and Neuroimaging Lab at the

University of California, Berkeley.

" Well, that's been one of the long-standing theories. But I think

what we're starting to understand is that sleep serves a whole

constellation of functions, plural, " explains.

One thing that's clear, says , is that sleep is critical. In a

series of studies done back in the 1980s, rats were kept awake

indefinitely. After just five days, they started dying.

says they started dying from sleep deprivation. " In fact,

sleep is as essential as food because they will die just about as

quick from food deprivation as sleep deprivation. So, it's that

necessary, " he says.

And it's not just rats: every animal studied so far needs sleep, from

the elephant right down to the fruit fly. But that's as far as the

similarities go. Some animals sleep 20 hours a day, others only two

or three. And still others sleep with half their brains at a time,

all making it hard to figure out what exactly it is about sleep that

makes it so essential, and that, in terms of evolution, makes it

worth the risks.

" You wonder why we developed this if survival is the whole point.

Because you're completely vulnerable when you're lying there, " Stahl

points out.

" Whatever the function of sleep, or the functions of sleep are, they

seem to be so important that evolution is willing to put us in that

place of potential danger by losing consciousness. It would be the

biggest evolutionary mistake if sleep does not serve some critical

function, " says.

One of the most exciting new discoveries in the field of sleep

research involves learning and memory.

Five college students were subjects in one of 's studies, and

they had been awake for more than 24 hours. He has found that

students like these do 40 percent worse memorizing lists of words

after a night without sleep. But he has discovered something far more

revolutionary about what happens when we do sleep.

" Sleep, we've been finding, actually can enhance your memories, so

that you'll come back the next day even better than where you were

the day before, " tells Stahl.

To prove it, put Stahl through a test he's given to more than

400 study subjects. Stahl had to type a series of numbers - 4, 1, 3,

2, 4 - over and over again with her left hand, making a new physical

memory.

CBS) By almost all measures, we are sleeping less than ever before.

In 1960, a survey by the American Cancer Society asked one million

Americans how much sleep they were getting a night. The median answer

was eight hours. Today that number has fallen to 6.7 hours - that's a

decrease of more than 15 percent in less than a lifetime. And from

what the scientists 60 Minutes met are finding, we may be putting

ourselves in a perilous situation.

Eve Van Cauter, an endocrinologist at the University of Chicago

School of Medicine, studies the effect of sleep on the body. At her

lab, healthy, young volunteers like Mrock are paid to come

one at a time and have virtually every system in their bodies

monitored while their sleep is interfered with.

" We did a study where we restricted sleep to four hours per night for

six nights, " Van Cauter explains. " And we noticed that they were

already in a pre-diabetic state. And so, that was a big finding. "

The study's subjects were on the road to diabetes in just six days,

and that's not all - they were also hungry. Van Cauter has made a

radical discovery: that lack of sleep may be contributing to the

epidemic of obesity in this country through the work of a hormone

called leptin that tells your brain when you're full.

" We observed that the volunteers, they actually had a drop in leptin

levels, " Van Cauter explains. " Leptin was telling the brain, 'Time to

eat. We need more food.' "

" Even though they'd eaten, " Stahl remarks.

" But in fact they had plenty of food, " Van Cauter agrees.

Several large-scale studies from all over the world have reported a

link between short sleep times and obesity, as well as heart disease,

high blood pressure, and stroke.

" I think it tells us that sleep deprivation is not a challenge for

which biology has wired us. There's no other mammal that sleep

deprives itself than the human. So it is read by our biology as a

stress, " Van Cauter says.

Van Cauter and Tasali are investigating a novel theory that some of

the health problems we typically associate with old age may in fact

be caused by the loss of deep sleep.

" We lose deep sleep at a very early age. So a young, healthy person

may have 100 minutes of deep sleep, and at 50 years old it may be as

little as 20 minutes. So it really… goes down very quickly, " Van

Cauter explains.

Tasali's goal is to turn 19-year-old , sleep-wise, into a 70-

year-old.

The next morning - 346 sounds later - it's time for testing. Now

's going to have fat extracted from his body for analysis, go

through a PET scan to see how his brain is metabolizing sugar, and

between procedures, he's answering questions about how he feels. His

doctors assure 60 Minutes that will be fine once he goes

back to his normal sleep routine, but after four nights without deep

sleep they have found that, like prior study subjects, he is

hungrier, less alert, and most importantly, his body is no longer

able to metabolize sugar effectively, putting him temporarily at

increased risk for Type 2 diabetes.

" We usually think of diabetes as something that's a disease of old

age. But really it may be a disease of sleep deprivation, " Stahl

remarks.

" I would say that sleep deprivation may be a new risk factor for

diabetes, " Van Cauter says. " Not just aging, not just being

overweight or obese, not just having a family history of diabetes,

which are the three major risk factors. But this is an added one. And

we have really an epidemic of diabetes now. And Type 2 diabetes is

now occurring in children, in adolescents. And, you know, adolescents

and children too are also being sleep deprived. Maybe high schoolers

are amongst the most sleep deprived individuals in our society,

because they have an enormous sleep need - nine to ten hours. Yet

they sleep less than seven hours per night. "

She says this research proves we all need to rethink what we consider

essential for good health - that the diet and exercise formula also

has to include sleep. " You know, our attitude about sleep flies in

the face of what you're saying. Because I think that 'You don't need

as much sleep' is looked upon as something very positive, " Stahl

remarks.

" Humans love to keep asking, 'Can't we just get rid of sleep?' If you

had a poll in the United States and said, 'If we could safely

eliminate half of the time you sleep. And you wouldn't suffer any

deficit, you'd be good to go.' We could just magically make sleep go

away. How many people would want it? And I believe you'd find the

population votes easily overwhelmingly for it, " Dinges

predicts. " And yet I think the hedonic joy of sleeping and the need

for sleep and how good it feels…I would have to say that

consciousness, wake-consciousness is probably a bit overrated. "

Asked if she thinks we're going to figure out a way to get along with

less sleep, Eve Van Cauter tells Stahl, " I hope not. "

" You don't think that's where research should put its effort? " Stahl

asks.

" You know, Lesley, my impression is that sleep affects so many

aspects of mental and physical function, that there's not going to be

one magic bullet drug that will be able to compensate. Much better

idea is simply to sleep an hour more, " she says.

Well, what about an afternoon cat nap? Some new research is showing

that what counts is getting your seven and a half to eight hours

total. So naps do help. But not all the scientists are convinced

that's as good as sleeping straight through the night.

========================

Carruthers

Wakefield, UK

[Guest guest]

The link doesn't seem to work...

[Try:

http://www.cbsnews.com/stories/2008/03/14/60minutes/main3939721.shtml?source=sea\

rch_story]

Guy Holland

City? United Kingdom

The Science Of Sleep

The below may be of some interest:

The Science Of Sleep

http://www.cbsnews. com/stories/ 2008/03/14/ 60minutes/ main3939721_ page1.

shtml

We don't sleep just to rest our tired bodies? " Stahl asks

, the director of the Sleep and Neuroimaging Lab at the

University of California, Berkeley.

" Well, that's been one of the long-standing theories. But I think

what we're starting to understand is that sleep serves a whole

constellation of functions, plural, " explains.

One thing that's clear, says , is that sleep is critical. In a

series of studies done back in the 1980s, rats were kept awake

indefinitely. After just five days, they started dying.

says they started dying from sleep deprivation. " In fact,

sleep is as essential as food because they will die just about as

quick from food deprivation as sleep deprivation. So, it's that

necessary, " he says.

And it's not just rats: every animal studied so far needs sleep, from

the elephant right down to the fruit fly. But that's as far as the

similarities go. Some animals sleep 20 hours a day, others only two

or three. And still others sleep with half their brains at a time,

all making it hard to figure out what exactly it is about sleep that

makes it so essential, and that, in terms of evolution, makes it

worth the risks.

" You wonder why we developed this if survival is the whole point.

Because you're completely vulnerable when you're lying there, " Stahl

points out.

" Whatever the function of sleep, or the functions of sleep are, they

seem to be so important that evolution is willing to put us in that

place of potential danger by losing consciousness. It would be the

biggest evolutionary mistake if sleep does not serve some critical

function, " says.

One of the most exciting new discoveries in the field of sleep

research involves learning and memory.

Five college students were subjects in one of 's studies, and

they had been awake for more than 24 hours. He has found that

students like these do 40 percent worse memorizing lists of words

after a night without sleep. But he has discovered something far more

revolutionary about what happens when we do sleep.

" Sleep, we've been finding, actually can enhance your memories, so

that you'll come back the next day even better than where you were

the day before, " tells Stahl.

To prove it, put Stahl through a test he's given to more than

400 study subjects. Stahl had to type a series of numbers - 4, 1, 3,

2, 4 - over and over again with her left hand, making a new physical

memory.

CBS) By almost all measures, we are sleeping less than ever before.

In 1960, a survey by the American Cancer Society asked one million

Americans how much sleep they were getting a night. The median answer

was eight hours. Today that number has fallen to 6.7 hours - that's a

decrease of more than 15 percent in less than a lifetime. And from

what the scientists 60 Minutes met are finding, we may be putting

ourselves in a perilous situation.

Eve Van Cauter, an endocrinologist at the University of Chicago

School of Medicine, studies the effect of sleep on the body. At her

lab, healthy, young volunteers like Mrock are paid to come

one at a time and have virtually every system in their bodies

monitored while their sleep is interfered with.

" We did a study where we restricted sleep to four hours per night for

six nights, " Van Cauter explains. " And we noticed that they were

already in a pre-diabetic state. And so, that was a big finding. "

The study's subjects were on the road to diabetes in just six days,

and that's not all - they were also hungry. Van Cauter has made a

radical discovery: that lack of sleep may be contributing to the

epidemic of obesity in this country through the work of a hormone

called leptin that tells your brain when you're full.

" We observed that the volunteers, they actually had a drop in leptin

levels, " Van Cauter explains. " Leptin was telling the brain, 'Time to

eat. We need more food.' "

" Even though they'd eaten, " Stahl remarks.

" But in fact they had plenty of food, " Van Cauter agrees.

Several large-scale studies from all over the world have reported a

link between short sleep times and obesity, as well as heart disease,

high blood pressure, and stroke.

" I think it tells us that sleep deprivation is not a challenge for

which biology has wired us. There's no other mammal that sleep

deprives itself than the human. So it is read by our biology as a

stress, " Van Cauter says.

Van Cauter and Tasali are investigating a novel theory that some of

the health problems we typically associate with old age may in fact

be caused by the loss of deep sleep.

" We lose deep sleep at a very early age. So a young, healthy person

may have 100 minutes of deep sleep, and at 50 years old it may be as

little as 20 minutes. So it really… goes down very quickly, " Van

Cauter explains.

Tasali's goal is to turn 19-year-old , sleep-wise, into a 70-

year-old.

The next morning - 346 sounds later - it's time for testing.. Now

's going to have fat extracted from his body for analysis, go

through a PET scan to see how his brain is metabolizing sugar, and

between procedures, he's answering questions about how he feels. His

doctors assure 60 Minutes that will be fine once he goes

back to his normal sleep routine, but after four nights without deep

sleep they have found that, like prior study subjects, he is

hungrier, less alert, and most importantly, his body is no longer

able to metabolize sugar effectively, putting him temporarily at

increased risk for Type 2 diabetes.

" We usually think of diabetes as something that's a disease of old

age. But really it may be a disease of sleep deprivation, " Stahl

remarks.

" I would say that sleep deprivation may be a new risk factor for

diabetes, " Van Cauter says. " Not just aging, not just being

overweight or obese, not just having a family history of diabetes,

which are the three major risk factors. But this is an added one. And

we have really an epidemic of diabetes now. And Type 2 diabetes is

now occurring in children, in adolescents. And, you know, adolescents

and children too are also being sleep deprived. Maybe high schoolers

are amongst the most sleep deprived individuals in our society,

because they have an enormous sleep need - nine to ten hours. Yet

they sleep less than seven hours per night. "

She says this research proves we all need to rethink what we consider

essential for good health - that the diet and exercise formula also

has to include sleep. " You know, our attitude about sleep flies in

the face of what you're saying. Because I think that 'You don't need

as much sleep' is looked upon as something very positive, " Stahl

remarks..

" Humans love to keep asking, 'Can't we just get rid of sleep?' If you

had a poll in the United States and said, 'If we could safely

eliminate half of the time you sleep. And you wouldn't suffer any

deficit, you'd be good to go.' We could just magically make sleep go

away. How many people would want it? And I believe you'd find the

population votes easily overwhelmingly for it, " Dinges

predicts. " And yet I think the hedonic joy of sleeping and the need

for sleep and how good it feels…I would have to say that

consciousness, wake-consciousness is probably a bit overrated. "

Asked if she thinks we're going to figure out a way to get along with

less sleep, Eve Van Cauter tells Stahl, " I hope not. "

" You don't think that's where research should put its effort? " Stahl

asks.

" You know, Lesley, my impression is that sleep affects so many

aspects of mental and physical function, that there's not going to be

one magic bullet drug that will be able to compensate. Much better

idea is simply to sleep an hour more, " she says.

Well, what about an afternoon cat nap? Some new research is showing

that what counts is getting your seven and a half to eight hours

total. So naps do help. But not all the scientists are convinced

that's as good as sleeping straight through the night.

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