|
 An article in the Public Library of Science Medicine (PLos Medicine) by sleep researchers from Bristol University along with colleagues from Stanford and University of Wisconsin studied 1,024 volunteers from the Wisconsin Sleep Cohort Study, a population-based study of sleep disorders. The participants underwent continuous sleep monitoring, and reported on their sleep habits through questionnaires and sleep diaries. The study found that individuals who habitually slept for 5 hours were found to have 15% more ghrelin than those who slept for 8 hours. They were also found to have 15% less leptin. Ghrelin increases feelings of hunger while leptin acts to suppress appetite. Essentially, individuals who spent less than 8 hours sleeping were shown to have a greater likelihood of being heavier.
Sleep duration may be an important regulator of body weight and metabolism. Over the last 50 years we have reduced the amount of time we spend asleep by up to two hours a night because of increasing pressures on our time (work, school, family, television, computer games and the internet). The research suggests that this lack of sleep may be contributing to the obesity pandemic. This is the first large population-based study to show a significant association between sleep duration and metabolic hormones.
These findings could explain, at least in part, why societies in which excess calories are much easier to come by than a good night's sleep are more prone to obesity. Additional studies are planned to evaluate the effect of sleep on body mass. According to the researchers, good sleep, healthy eating habits, and regular exercise each may have important roles in fighting obesity in modern society.
A similar study was reported by the North American Association for the Study of Obesity at their annual meeting last month. Researchers from Columbia University demonstrated a clear link of being obese and the number of hours of sleep each night, even after controlling for depression, physical activity, alcohol consumption, ethnicity, level of education, age, and gender. The study was an analysis of data taken from the National Health and Nutrition Examination Survey I (NHANES I). The researchers pointed out that "the results are somewhat counterintuitive, since people who sleep less are naturally burning more calories." It is believed that it has more to do with what happens to your body when you deprive it of sleep as opposed to the amount of physical activity that you get. Other studies have shown that leptin levels decrease and grehlin levels increase in people who are sleep-deprived, leading to increased appetite and consumption.
PLos Article (PDF)
PLos Medicine
North American Association for the Study of Obesity
National Health and Nutrition Examination Survey I Data
11:37:51 PM 
|
|
