ATLANTA - People who sleep fewer than six hours a night — or
more than nine — are more likely to be obese, according to a new
government study that is one of the largest to show a link between
irregular sleep and big bellies.
The study also linked light sleepers to higher smoking
rates, less physical activity and more alcohol use.
The research adds weight to a stream of studies that have found
obesity and other health problems in those who don't get proper
shuteye, said Dr. Ron Kramer, a Colorado physician and a spokesman for the American
Academy of Sleep Medicine.
The data is all coming together that short sleepers and long
sleepers don't do so well," Kramer said.
The study released Wednesday is based on door-to-door surveys of
87,000 U.S. adults from 2004 through 2006 conducted by the
National Center for Health Statistics, part
of the Centers for Disease Control and Prevention.
Such surveys can't prove cause-effect relationships, so — for
example — it's not clear if smoking causes sleeplessness or if
sleeplessness prompts smoking, said Charlotte Schoenborn, the
study's lead author.
It also did not account for the influence of other factors, such
as depression, which can contribute to heavy eating, smoking,
sleeplessness and other problems.
Smoking was highest for people who got under six hours of sleep,
with 31 percent saying they were current smokers. Those who got
nine or more hours also were big puffers, with 26 percent
smoking.
The overall U.S. smoking rate is about 21 percent. For those in
the study who sleep seven to eight hours, the rate was lower, at 18
percent.
Results were similar, though a bit less dramatic, for obesity:
About 33 percent of those who slept less than six hours were obese,
and 26 percent for those who got nine or more. Normal sleepers were
the thinnest group, with obesity at 22 percent.
For alcohol use, those who slept the least were the biggest
drinkers. However, alcohol use for those who slept seven to eight
hours and those who slept nine hours or more was similar.
In another measure, nearly half of those who slept nine hours or
more each night were physically inactive in their leisure time,
which was worse even than the lightest sleepers and the proper
sleepers. Many of those who sleep nine hours or more may have
serious health problems that make exercise difficult.
Many elderly people are in the group who get the least sleep,
which would help explain why physical activity rates are low. Those
skimpy sleepers who are younger may still feel too tired to
exercise, experts said.
Stress or psychological problems may
explain what's going on with some of the lighter sleepers, experts
said.
Other studies have found inadequate sleep is tied to
appetite-influencing hormone imbalances and a higher incidence of
diabetes and high blood pressure, noted James Gangwisch, a
respected Columbia University sleep
researcher.
"We're getting to the point that they may start recommending
getting enough sleep as a standard approach to weight loss and the
prevention of obesity," said Gangwisch, who was not involved in the
study.