Researchers Link Six Weeks of Poor Sleep to Weight Gain and Inactivity - Video

Losing just over an hour of sleep each night could quietly add extra weight over time. A new study from Columbia University and published in Annals of Internal Medicine found that adults who reduced their nightly sleep by about 80 minutes for six weeks gained an average of one pound and became more sedentary, highlighting the importance of adequate sleep for long-term health.

The researchers studied 95 healthy adults who typically slept seven to eight hours each night. Participants completed two six-week phases: one in which they delayed bedtime by 90 minutes, reducing sleep, and another in which they followed their normal sleep schedule. Throughout the study, wrist monitors tracked sleep and physical activity, while researchers measured body weight, waist circumference, body composition, and appetite-related hormones.

By the end of the sleep-restriction phase, participants had gained an average of one pound. Although the increase was modest, researchers noted that such weight gain could become clinically significant if poor sleep habits continue over months or years.

Sleep loss also affected daily activity. Participants spent an average of 17 more minutes per day being sedentary during the sleep-restricted period, with men and postmenopausal women showing increases of nearly 30 minutes daily. Even after accounting for the extra time they were awake, they were still less physically active than when they slept adequately.

The findings build on earlier research involving the same participants, which showed that mild sleep restriction increased insulin resistance in women with higher cardiometabolic risk, particularly postmenopausal women. Another related study also found increased inflammatory cells in the heart after prolonged mild sleep loss.

Researchers say these results suggest that even moderate, chronic sleep deprivation may contribute to weight gain and increase the risk of obesity-related conditions, including type 2 diabetes and heart disease. They emphasize that improving sleep habits could become an important strategy for maintaining a healthy weight and reducing long-term disease risk.

REFERENCE: Zuraikat, F. M., et al. (2026). Prolonged Short Sleep and Its Effect on Body Weight and Composition. Annals of Internal Medicine. DOI: 10.7326/annals-25-01660. https://www.acpjournals.org/doi/10.7326/ANNALS-25-01660