Losing Sleep, Gaining Weight

(May, 2013)  Healthy adults gain almost two pounds of weight when they get just five hours of sleep per night during a work week and have unlimited access to food, according to a study by researchers at the University of Colorado Boulder and the CU Anschutz Medical Campus.

For the study, researchers monitored 16 young, lean, healthy adults who lived for about two weeks in a “sleep suite” at the University of Colorado Hospital in Aurora.

During the first week, half the people were allowed to sleep nine hours a night while the other half could sleep up to five hours. Everyone was given unlimited access to food. In the second week, the nine-hour sleepers were restricted to five hours of sleep, while the previously sleep-deprived were allowed the extra sleep time.

“When people are sleep-restricted, our findings show they eat during their biological nighttime when internal physiology is not designed to be taking in food,” says Kenneth Wright, PhD, director of CU-Boulder’s Sleep and Chronobiology Laboratory.

The study results were published in March in the Proceedings of the National Academy of Sciences.

Co-authors of the study are Rachel Markwarld and Mark Smith, both postdoctoral researchers in the lab, and the following School of Medicine faculty members: Edward Melanson, PhD; Leigh Perreault, MD; Robert Eckel, MD; and Janine Higgins, PhD, from the Anschutz Medical Campus.