Losing just 80 minutes of sleep per night can have a greater impact on health than it might seem. Researchers from the Vagelos College of Physicians and Surgeons at Columbia University found that adults who reduced their nightly sleep by approximately 80 minutes over six weeks gained an average of one pound (about 0.45 kg) and spent more time in a sedentary state.
These findings contribute to a growing body of evidence that regular, sufficient sleep plays a crucial role in preventing weight gain and reducing the risk of obesity-related diseases. “Our study shows that adequate sleep can help reduce the risk of weight gain and obesity-related conditions such as heart disease and diabetes,” said Marie-Pierre St-Onge, a professor of nutritional medicine in the Department of Medicine and at the Institute of Human Nutrition at Columbia University, who also served as the lead researcher. She noted that people tend to gain weight throughout adulthood, and obesity is a significant risk factor for heart disease. However, focusing solely on a healthier diet and increasing physical activity to counteract weight gain is an oversimplified approach that is difficult to maintain.
Chronic mild sleep deprivation
A significant portion of previous studies linking poor sleep to obesity has focused on severe sleep deprivation, often limiting it to just four hours. These studies demonstrated that extreme sleep loss can increase appetite and lead to overeating, contributing to weight gain. However, such severe sleep restriction is challenging for most people to endure for more than a few days.
“These studies only show us what happens under extreme conditions and do not tell us whether people with mild sleep deprivation, like many Americans who sleep 5 or 6 hours a day, will gain weight,” explained St-Onge. To better reflect real-world conditions, researchers examined the effects of chronic, mild sleep loss, which affects about 30% of adults. The study involved 95 adults who typically slept between 7 to 8 hours each night.
Less sleep — more sitting
During one six-week period of the study, participants went to bed 90 minutes later. In another six-week period, they followed their usual sleep schedule. Throughout both phases, participants wore wrist monitors that tracked their sleep and physical activity. Researchers also measured body weight, waist circumference, body composition, and levels of several hormones involved in appetite regulation.
“Although the weight gain of one pound observed with moderate sleep reduction is not extreme, it is important to remember that this occurred in just six weeks,” noted Faris Zuraikat, an assistant professor of nutritional medicine in the Department of Medicine and at the Institute of Human Nutrition at Columbia University, who was the first author of the study. He added that the study was designed to mimic sleep patterns that many adults experience chronically. Over the course of a full year, losing less than an hour and a half of sleep per night could lead to clinically significant weight gain.
Researchers found that participants became less active during the sleep restriction phase. On average, the time spent in a sedentary position increased by 17 minutes per day. Among men and postmenopausal women, sedentary time increased by nearly 30 minutes daily. “Even accounting for the fact that they stayed awake longer due to reduced sleep, participants still spent more time in a sedentary state than when they got adequate sleep,” said Zuraikat. Individuals who lead a more sedentary lifestyle face an increased risk of chronic diseases.
The same group of participants was also studied in related research. In one study, women with elevated cardiometabolic risk who reduced their sleep by approximately 80 minutes each night for six weeks showed increased insulin resistance — a significant risk factor for type 2 diabetes. This effect was particularly pronounced in postmenopausal women. Another study revealed that in men and women with an elevated risk of heart disease, moderate sleep restriction led to the accumulation of inflammatory cells in heart tissue.
“While additional research is needed to better understand how sleep restriction leads to weight gain, all our findings suggest that insufficient sleep increases the risk of obesity-related diseases, including type 2 diabetes and heart disease. The next step should be to study how improving sleep affects the health of people who regularly do not get enough sleep,” summarized Marie-Pierre St-Onge. The study titled “Sleep curtailment and its effects on weight and body composition: a pooled analysis of randomized studies” was published on July 6 in the journal Annals of Internal Medicine.
