Right amount of sleep essential
2008-05-07 22:27
Atlanta - People who sleep fewer than six hours a night - or more than nine - are more likely to be obese, according to a new US-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 added weight to a stream of studies that have found obesity and other health problems in those who do not get proper sleep, said Dr Ron Kramer, a Colorado physician and a spokesperson for the American Academy of Sleep Medicine.
Short and long sleepers 'don't do well'
"The data is all coming together that short sleepers and long sleepers don't do so well," Kramer said.
The study was based on door-to-door surveys of 87 000 US adults from 2004 through 2006 conducted by the National Centre for Health Statistics, part of the Centres for Disease Control and Prevention.
Such surveys cannot prove cause-effect relationships, so, for example, it was not clear if smoking caused sleeplessness or if sleeplessness prompted smoking, said Charlotte Schoenborn, the study's lead author.
It also did not account for the influence of other factors, such as depression, which could contribute to heavy eating, smoking, sleeplessness and other problems.
Short sleepers smoke and drink most
Smoking was highest for people who got under six hours of sleep, with 31% saying they were current smokers. Those who got nine or more hours also were big puffers, with 26% smoking.
Results were similar, though a bit less dramatic, for obesity: About 33% of those who slept less than six hours were obese, and 26% for those who got nine or more. Normal sleepers were the thinnest group, with obesity at 22%.
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.
Long sleepers exercise least
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 could have serious health problems that make exercise difficult.
Stress or psychological problems could explain what was going on with some of the lighter sleepers, experts said.
- AP