Columbia University study links 80‑minute nightly sleep loss to weight gain

Researchers at Columbia University’s Vagelos College of Physicians and Surgeons conducted a six‑week experiment in which 95 healthy adults reduced their nightly sleep by roughly 80‑90 minutes. Participants, who normally slept seven to eight hours, ended the trial averaging 5.5–6 hours of sleep per night. By the end of the period they had gained an average of 0.45 kg (about one pound), their waist circumference increased, and they spent about 17 minutes more per day in sedentary activities. The weight gain and added inactivity were observed despite the extra waking hours, suggesting that mild chronic sleep restriction can alter metabolism and behavior. Lead investigators Faris Zuraikat and Marie‑Pierre St‑Onge noted that the findings reinforce earlier evidence that inadequate sleep disrupts hunger hormones, raises blood pressure, and may elevate long‑term risks of type‑2 diabetes and cardiovascular disease. The study, published in Annals of Internal Medicine, has been reported in media outlets in the United States, Romania, and Italy.