You shouldn’t have to wait until daylight savings ends to get that long-awaited extra hour of sleep, and a new study sheds light as to why you may wish to hit the hay a little sooner each night. A study just published in the Annals of Internal Medicine randomized 10 overweight or obese individuals to receive either 8.5 hours of sleep or 5.5 hours over a 14-day period of time (1). Each group consumed a moderate calorie-restricted diet. Although the duration and the number of individuals in the study was short and small, those who received 5.5 hours of sleep were 55 percent less likely to have any weight they lost coming from stored fat and 60 percent more likely to lose muscle mass. In addition, lack of sleep led to increased hunger and changes in metabolism. This makes perfect sense since it is known from previous studies that sleep deprivation increases both insulin levels (making it difficult to access stored body fat) and cortisol levels (that leads to breakdown of muscle mass). Who wouldn’t want a prescription to get more sleep, and wouldn’t it be a shame to work so hard to reduce your calorie intake only to find out you were cannibalizing your muscles rather than losing your stored body fat? So here’s to getting those Zzzzzzzzzzz’s.
- Nedeltcheva, A.V, J.M. Kilkus , J. Imperial, D.A. Schoeller, P.D. Penev. Insufficient Sleep Undermines Dietary Efforts to Reduce Adiposity. Ann Intern Med 153:435-441 (2010).