Reducing sleep by as little as 80 minutes per night can lead to weight gain at a rate of approximately one pound every six weeks, according to a study from Columbia University. The research, which focused on a more common scenario of mild sleep deprivation rather than extreme restriction, also found that individuals who skimp on sleep tend to spend more time sitting during the day, further amplifying health risks.
Professor Marie-Pierre St-Onge, who led the study, indicated that adequate sleep may help lower the risk of weight gain and obesity-related conditions such as heart disease and diabetes. "People tend to gain weight over the course of their adulthood, and obesity is a major risk factor for heart disease," she stated.
The study involved 95 adults who typically slept seven to eight hours per night. For one six-week period, they were asked to delay their bedtime by 90 minutes, followed by a six-week period of sleeping their usual amount. Participants wore wrist monitors to track sleep duration, and their body weight, waist circumference, body composition, and fasting hormone levels related to appetite were measured.
Faris Zuraikat, assistant professor of nutritional medicine at Columbia and the study's first author, noted that while the observed weight gain of about one pound over six weeks might not seem substantial, it occurs over a short period. He suggested that when extrapolated to a full year, losing less than an hour and a half of sleep per night could result in clinically significant weight gain. Participants in the study averaged about 80 minutes less sleep per night.
During the six-week period of reduced sleep, sedentary time increased by an average of 17 minutes per day. This increase was nearly 30 minutes per day for men and postmenopausal women. "Even when we accounted for the fact that they were awake longer when sleep was shortened, participants spent more time being inactive than when they got adequate sleep," Zuraikat said. "This is notable, as people who are more sedentary have elevated risk for chronic diseases."
Previous findings from the same research group indicated that women with increased cardiometabolic risk who reduced their sleep by about 80 minutes a night over six weeks showed increased insulin resistance, a precursor to type 2 diabetes, with more pronounced effects in postmenopausal women. Another related study of the same participants found an increase in inflammatory cells in the heart among men and women with elevated heart risk after sleep loss.
While further research is needed to fully elucidate the mechanisms by which sleep restriction leads to weight gain, the findings collectively suggest that insufficient sleep elevates the risk for obesity-related conditions like type 2 diabetes and heart disease. The researchers aim to further understand the health benefits associated with improving sleep in individuals who habitually get inadequate sleep.