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A growing number of Americans are both overweight and sleep deprived, and there
is mounting evidence that the two are related. Several recent studies have
suggested that sleep deprivation may at least partially explain the epidemic of
obesity in the U.S, and research strengthens the argument.
Sleep Times Predicted Weight
Investigators surveyed roughly 1,000 people about their sleep patterns and also
determined if they were normal weight, overweight, or obese by calculating
their body mass index. Total sleep times tended to decrease as body weight
increased, with the exception of people who were morbidly obese.
The difference in total sleep time between patients who were normal weight and
those who weren't was only 16 minutes per day, or 1.86 hours over a week.
The findings are reported in the Jan. 10, 2005 issue of the Archives of Internal
Medicine .
Lead researcher Robert D. Vorona, MD, says even though his study does not prove
that sleep deprivation leads to obesity, the research as a whole certainly
points in that direction. Vorona is an assistant professor of internal medicine
and a sleep specialist at Eastern Virginia Medical School.
"Obviously there are reasons besides curtailed sleep to explain why Americans
are increasingly obese," he tells WebMD. "Lack of exercise, supersized
portions, and other things are certainly important. But it is also very
possible that the reductions in sleep that so many of us are experiencing may
also be playing a role."
Sleep, Obesity 'A Two-Way Street'
According to a poll conducted in 2000 by the National Sleep Foundation, the
average American gets just under seven hours of sleep each night -- about an
hour less than is optimal for most people. That is about 90 minutes less than
Americans tended to sleep in the early 1900s.
Psychologist Michael Breus, PhD, who specializes in treating sleep problems,
tells WebMD that sleeping eight hours or more each night doesn't necessarily
mean a person isn't sleep deprived. Obese people often suffer from sleep apnea,
a condition characterized by repeated waking during the night leading to
poor-quality sleep.
"It really does appear that sleep and obesity are a two-way street," he says.
"Bad sleep may lead to weight gain, and weight gain can lead to bad sleep."
Recent studies suggest that sleep deprivation plays a role in the secretion of
appetite-regulating hormones, increasing levels of a hormone that triggers
hunger and reducing levels of one that signals fullness.
Eat Less, Exercise, and Get Those Zzzs
So is it time to include "Get more sleep" in the dieter's mantra of "Eat less
and exercise more"? The experts say yes.
Fred Turek, MD, who directs the sleep center at Northwestern University, says
raising public awareness about the link between sleep deprivation and weight is
a top priority because obesity is a leading cause of death and illness in
America.
"Sleep is really a behavior that has been ignored," he tells WebMD. "Everybody
talks about diet and exercise, but nobody pays much attention to sleep."
Vorona says he hopes to get funding for an intervention study to measure the
impact of sleep times on the success or failure of people trying to lose
weight.
"If we were able to show that increasing sleep actually aids in weight loss,
that would go a long way to proving cause and effect," he says.
By Salynn Boyles
Reviewed By Kathleen Zelman, MPH, RD, July 25, 2007.
Medically updated July 25, 2007.
SOURCES: Vorona, R. Archives of Internal Medicine , Jan.
10, 2005; vol 165: pp 25-30. Robert D. Vorona, MD, assistant professor of
internal medicine, Eastern Virginia Medical School, Virginia Beach, Va. Michael
Breus, PhD, sleep medicine specialist, Atlanta. Fred Turek, MD, professor and
director of the Center of Sleep and Circadian Biology, Northwestern University
Feinberg School of Medicine, Evanston, IL.
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