MORNINGSIDE HEIGHTS, N.Y., July 28 (Our New York News) — For many people, the practical question is simple: does shaving an hour or so off sleep for weeks really matter? Columbia University researchers in New York City say it can.
What the study found
In a study published in Annals of Internal Medicine, adults who slept about 80 to 90 minutes less per night for six weeks gained about 1 pound on average. The same participants also became a little more sedentary and saw a small increase in waist size.
Sedentary time means time spent sitting or lying down with little movement.
The average change in waist circumference was modest, at about half a centimeter. That is not a dramatic shift, but it points in the same direction as the weight gain: less sleep was linked with a small move toward more body weight and less activity.
Why does that matter?
A 1-pound gain over six weeks may sound minor, and the researchers did not report major changes in body fat or muscle mass. But the study’s first author, Faris Zuraikat of Columbia University, said the pattern could become more meaningful if it adds up over a year.
The Columbia team said the study was designed to mimic the kind of chronic sleep loss many adults experience in daily life.
How sleep loss may affect the body
The study followed 95 adults already at risk for heart or metabolic disease and compared periods of adequate sleep with periods of sleep restriction. During the shorter-sleep phase, participants spent an average of 17 more minutes per day being sedentary.
Among men and postmenopausal women, sedentary time rose by nearly 30 minutes per day.
That matters because even small changes in daily movement can affect how many calories a person uses across a day. The study did not suggest that sleep loss caused a sudden or extreme health change. Instead, it showed a slow pattern: less sleep, less movement, and a small average gain in weight and waist size.
What the study does not show
The findings do not mean one short night will automatically lead to weight gain. The trial looked at repeated sleep restriction over six weeks, not a single late night.
The researchers also did not report a crisis-level change. The average gain was small. But for readers trying to understand whether sleep is only about feeling rested, the study suggests it may also be part of the body weight picture.
In other words, sleep is not just downtime. In this Columbia study, trimming it by a little each night was linked with a slight shift toward more sitting and more weight gain over time.
