Losing 80 Minutes of Sleep Each Night Can Lead to Weight Gain, Study Finds
A Columbia University study found that adults who lost about 80 minutes of sleep per night gained an average of one pound over six weeks. Researchers say the weight gain was driven mainly by increased inactivity, not by eating more.
Adults who cut their sleep by about 80 minutes a night gained an average of one pound over six weeks, according to a study published in the Annals of Internal Medicine.
Researchers at Columbia University's Vagelos College of Physicians and Surgeons tracked 95 adults who normally slept seven to eight hours a night. Participants were asked to delay their bedtime by 90 minutes for six weeks, simulating the kind of mild sleep loss that many people experience regularly.
The weight gain was modest, but researchers said the pattern is significant. One pound in six weeks, if sustained over a year, adds up to meaningful weight gain. The study also found that participants became more sedentary, spending an average of 17 minutes more per day sitting or lying down. Men and postmenopausal women showed even larger increases, close to 30 minutes of additional inactivity per day.
Dr. Marie-Pierre St-Onge, who led the research, said the findings challenge the assumption that sleep deprivation leads to weight gain mainly through increased appetite. In this study, the bigger driver was reduced physical activity. Sleep-deprived participants simply moved less.
The study also found metabolic effects. Women at risk for cardiometabolic disease developed increased insulin resistance during the sleep restriction period. Participants with elevated heart risk showed signs of cardiac inflammation.
Researchers said sleep should be treated as a health priority alongside diet and exercise. Practical steps include setting a consistent wake time, counting backward to find an appropriate bedtime, and avoiding caffeine and heavy meals in the hours before sleep.
