Missing just over an hour of sleep each night could have lasting effects on your waistline.

A new study found that adults who slept about 80 minutes less than usual each night for six weeks gained an average of 1 pound and became more sedentary, suggesting that even mild sleep deprivation may contribute to weight gain over time.

Researchers at Columbia University Vagelos College of Physicians and Surgeons say the findings add to growing evidence that consistently getting too little sleep can increase the risk of obesity and related health problems.

When projected over a year, even a one-pound weight gain over six weeks could become clinically meaningful, according to Medical News Today.

The study, titled "Skimping on Sleep and Its Impact on Body Weight and Composition: A Pooled Analysis of Randomized Trials," was published in the Annals of Internal Medicine.

"Our study shows that getting adequate sleep may help reduce the risk of weight gain and obesity-related conditions like heart disease and diabetes," says Marie-Pierre St-Onge, a professor of nutritional medicine in Columbia's Department of Medicine and Institute for Human Nutrition and study leader.

"People tend to gain weight over the course of their adulthood, and obesity is a major risk factor for heart disease. But focusing on eating a healthier diet and getting more physical activity to offset weight gain is simplistic and can be difficult to maintain,” she adds.

To examine the effects of chronic, mild sleep deprivation—a pattern estimated to affect about 30% of adults—researchers enrolled 95 adults who normally slept seven to eight hours each night. During one six-week phase, participants delayed their usual bedtime by 90 minutes. During another six-week phase, they followed their normal sleep schedule.

Throughout the study, researchers used wrist monitors to track sleep and physical activity. They also measured body weight, waist circumference, body composition, and fasting levels of hormones involved in regulating appetite.

During the sleep-restriction phase, participants gained an average of 1 pound, and their waist circumference increased by an average of 0.52 centimeters over six weeks.

Participants also spent an average of 17 more minutes per day being sedentary during the sleep-restriction phase. Among men and postmenopausal women, sedentary time increased by nearly 30 minutes a day. Because spending less time sitting is linked to a lower risk of chronic disease, the researchers say the findings suggest that insufficient sleep may contribute to unhealthy lifestyle habits as well as weight gain.

"Though more research is needed to further understand how sleep restriction leads to weight gain, all of our findings suggest that insufficient sleep increases the risk of obesity-related conditions like Type 2 diabetes and heart disease," St-Onge says. "Now we need to understand the health effects of improving sleep in those who fail to get adequate sleep on a regular basis."