Study links modest sleep loss to weight gain and inactivity

A Columbia University analysis published in Annals of Internal Medicine found that trimming sleep by 78.4 minutes a night for six weeks led adults to gain 0.45 kilogram, or about one pound, while sedentary time rose by 17.2 minutes a day. The pooled study combined two randomized crossover trials with 95 adults age 20 and older who were already at elevated cardiometabolic risk and usually slept seven or more hours a night.

Researchers asked participants to delay bedtime by 90 minutes for one six-week phase and then return to their usual sleep schedule for another phase. Wrist monitors tracked sleep and activity, while the team measured body weight, waist circumference, body composition and fasting appetite hormones. During the sleep-restriction phase, waist circumference increased by 0.52 cm and leptin rose by 2.03 ng/mL.

The size of the changes was modest, but the pattern matters because the intervention was built to mirror the kind of chronic short sleep many adults accept when they stay up later than planned and still wake to the same alarm. Columbia said about 30% of adults have a similar pattern of short sleep, which makes the finding more relevant to everyday routines than to extreme sleep deprivation.

The results also fit earlier Columbia work in women with higher cardiometabolic risk, where cutting sleep by about 90 minutes a night for six weeks increased insulin resistance, with the effect more pronounced in postmenopausal women. Marie-Pierre St-Onge and first author Faris Zuraikat framed the intervention as a realistic chronic sleep deficit, not a laboratory exercise in exhaustion, because the concern is not one all-nighter but a repeated nightly cut that can push appetite signals, movement and energy balance in the wrong direction. For weight management and prevention of obesity-related conditions such as heart disease and diabetes, that makes sleep part of the equation rather than an afterthought.