Even modest reductions in nightly sleep can nudge the scales upward and tilt daily habits toward inactivity. That is the central finding from researchers at Columbia University Irving Medical Center, whose pooled analysis of two randomised controlled trials appeared in the Annals of Internal Medicine on 6 July 2026.
The work examined 95 adults who usually slept seven to eight hours per night. Over six weeks they delayed bedtime by 90 minutes, producing an average sleep curtailment of about 80 minutes. Participants gained one pound on average. Their daily sedentary time rose by 17 minutes, climbing to roughly 30 minutes among men and postmenopausal women.
Measurements relied on wrist monitors that tracked sleep and activity, alongside assessments of body weight, waist circumference, body composition and fasting hormone levels. The design deliberately mirrored the mild, chronic sleep restriction many adults experience in ordinary life rather than the extreme deprivation studied previously.
While the one-pound weight gain observed with modest sleep curtailment is not overwhelming, it is important to remember this is occurring over just six weeks.
Faris Zuraikat, assistant professor of nutritional medicine at Columbia’s Department of Medicine and Institute for Human Nutrition and first author of the paper, offered that caution. He added that even after accounting for extra waking hours, participants still chose more inactive time than when they slept adequately.
Marie-Pierre St-Onge, professor of nutritional medicine at the same institutions and leader of the study, placed the results in a broader health context.
Our study shows that getting adequate sleep may help reduce the risk of weight gain and obesity-related conditions like heart disease and diabetes.
Related lines of research connected to this work have noted increased insulin resistance in women and an influx of inflammatory cells in heart tissue. Together the findings point to measurable shifts in energy balance, physical activity and cardiometabolic markers when sleep slips by roughly an hour and a quarter each night.
