Does Sleep Loss Up Weight by Lowering Energy Use?

NEW YORK (Reuters Health) - Sleep deprivation makes the day drag and appears to put a drag on metabolism, causing the body to use less energy, European researchers found in a small study.

The results, which appear in the American Journal of Clinical Nutrition, add to evidence that a lack of shut-eye can promote weight gain—not just by boosting hunger, but by slowing the rate at which calories get burned.

The study suggests that getting plenty of sleep might prevent weight gain, said Dr. Christian Benedict of the Uppsala University in Sweden, who led the new work.

Approximately 50 to 70 million Americans—including a significant number of shift workers—suffer from chronic sleep loss and sleep disorders, according to the National Institutes of Health.

Previous studies have linked sleep deprivation with weight gain, and shown how disrupted sleep also disrupts levels of stress- and hunger-related hormones during waking hours.

To help identify the exact mechanisms by which a lack of sleep might pack on the pounds, Benedict and his colleagues put 14 male university students through a series of sleep "conditions" - curtailed sleep, no sleep, and normal sleep - over several days, then measured changes in how much they ate, their blood sugar, hormone levels and indicators of their metabolic rate like oxygen use.

The team found that even a single night of missed sleep slowed the volunteers' metabolisms the next morning, reducing their bodies' energy expenditure for tasks like breathing and digestion by 5 to 20 percent, compared with the morning after a good night's sleep.

The young men also had higher morning levels of blood sugar, appetite-regulating hormones like ghrelin, and stress hormones like cortisol after sleep deprivation. Still, the sleep loss did not boost the amount of food the men consumed during the day.