MORNINGSIDE HEIGHTS, N.Y., July 28 (Our New York News) — Cutting sleep by a little under two hours a night may not feel dramatic in the moment, but a Columbia University study suggests the effect can still show up on the scale. Over six weeks, adults who slept about 80 to 90 minutes less than usual gained about 1 pound on average and spent more time being sedentary, according to Columbia University Vagelos College of Physicians and Surgeons.
Sedentary time means time spent sitting or lying down with little physical movement. The study also found a modest increase in waist size during the sleep-restriction phase, according to the paper published in Annals of Internal Medicine.
The researchers said the pattern matters because it adds up. Faris Zuraikat, the study’s first author and an assistant professor in Columbia’s Department of Medicine and Institute for Human Nutrition, said, “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.” He added that if the same sleep loss continued for a year, losing less than an hour and a half of sleep per night could lead to clinically meaningful weight gain.
The study compared periods of adequate sleep with periods of shorter sleep in adults who were already at elevated risk for heart or metabolic disease. That short-term design matters: the findings do not mean every person will gain the same amount from a few late nights, but they do suggest that repeated sleep loss can affect body weight and daily activity over time.
The paper did not report major shifts in body fat or muscle mass over the short study window. Even so, the Columbia team’s message was simple: sleep is part of the body-weight equation, and shaving off sleep night after night may have a measurable effect even when the change seems small.
