Obesity and Sleep Trouble sleeping? By Harry Jackson Jr. ST. LOUIS POST-DISPATCH Monday, Aug. 20 2007
If you can't tame your appetite and your weight keeps rising, you may not be
getting enough sleep.
Poor sleep habits have become so closely associated with obesity that some
scientists want obesity therapists to address sleep with the same intensity as
diet and exercise, according to the National Sleep Foundation.
"There's an association between (poor, inadequate) sleep and obesity," says Dr.
Joseph Ojile, head of the Clayton Sleep Institute.
There's also a double whammy, says Dr. Joseph Espiritu, an expert in sleep
medicine with St. Louis University School of Medicine.
Once you're obese, you're more prone to sleep apnea, the collapse of the upper
windpipe which interrupts breathing during sleep. That's the vicious circle:
sleep apnea can help cause obesity, and obesity can cause sleep apnea.
THE SMOKING GUN
For decades, studies found that overweight and obese people tended to have poor
sleep habits. But all the evidence was statistical, not scientific.
The physiological proof — albeit in a relatively small study — came in December
of 2004 when a University of Chicago researcher in endocrinology, Eve van
Cauter, found that poor sleep disrupted two hormones associated with appetite.
It works this way:
Sleep and insulin choreograph the dance between leptin, which tells the brain
there's no need for food, and ghrelin, which tells the brain it's chow time.
Poor sleep, researchers learned, causes the dancers to start tripping over one
another.
Here's what happened: The test subjects slept only four hours a night rather
than eight. In only two nights, the hormones malfunctioned.
Leptin production decreased by 18 percent; ghrelin production increased by 28
percent.
On top of that, the test subjects — healthy, young, male college students —
started eating like they were at a frat party. They reported craving more
high-calorie, high-density, high-carbohydrate foods — including a 24 percent
increase in appetite for candy, cookies, chips, nuts and starchy foods such as
bread and pasta.
A week into the experiment, blood tests showed an inability to use insulin so
intense that it mimicked diabetes. Also, lack of sleep increased the production
of cortisol, a hormone associated with increased belly fat.
The researchers concluded that sleep starvation boosted appetite; increased
appetite caused overeating; overeating caused weight gain; and weight gain
causes obesity.
A major effect of the study has been to change the medical community's
perception that sleep problems only cause mental problems, not physical
problems, experts say.
While the medical community is encouraged, researchers want bigger studies on a
bigger selection of people and a wider range of physiological effects before
saying poor sleep actually "causes" obesity.
"But the association is clear," Ojile says. "As a health-conscious society,
this is enough data that we should incorporate good sleep health into our total
health package.
"If I'm going to go exercise, watch my diet, go low-fat, good sleep should be
part of that."
As for the test subjects from the University of Chicago study, all of them
returned to normal health immediately upon paying their "sleep debt," the
amount of sleep they lost during they study.
IT'S IN USE
Dietitian Lisa Galati of St. Anthony's Medical Center says that, after 25 years
of connecting the dots, she found that many of her clients who needed help with
obesity also needed help with sleeping problems.
One of the first questions she asks her patients is how much sleep are they
getting. "They look at me as if to say, 'Why are you asking that?'"
She says she finds a concentration of people with sleep-weight problems in
high-tension corporate jobs. She sends them to their doctors for sleep
assessments, she says.
After a while, she says, "They come back to me and say they're feeling better
or they had sleep apnea and didn't know it."
Among her first questions are: Do you sleep uninterrupted for at least seven
hours a night? And do you wake up and have trouble returning to sleep or do you
go over your work or get up and get something to eat?
"I know their sleeping pattern is a whole part of the package," Galati says.
"Those are the people who will be less motivated to make changes in their lives
because during the day they're just tired."
STATISTICS
The parallel between sleep deprivation and American weight gain has nudged
scientists for decades.
The University of Chicago study and the National Sleep Foundation note that in
1960 only one out of four adults was overweight and about one out of nine was
considered obese.
By 2002, two out of three adults were overweight and nearly one out of three
obese.
In that same time period, American adults cut their average sleep time by
nearly two hours. In 1960, U.S. adults slept an average of 8.5 hours a night.
By 2002, that had fallen to less than seven hours a night.
Meanwhile, doctors in sleep therapy centers generally don't see patients for
obesity problems. Patients visit for sleep problems, and weight loss might be a
byproduct.
POST-DISPATCH NEWS SERVICES CONTRIBUTED TO THIS STORY.
Obesity and Sleep