Reducing sleep by 1.5 hours per night linked to weight gain and inactivity

A new study published in Annals of Internal Medicine finds that reducing sleep by about 1.5 hours per night for six weeks leads to an average weight gain of 0.45 kg (1 lb) and increased sedentary behavior in adults with elevated cardiometabolic risk. Conducted by researchers at Columbia University, the study involved 95 adults who normally slept 7–8 hours per night. Participants underwent two six-week phases: one with their usual sleep and another where they delayed bedtime by ~90 minutes.

Key findings

• Weight gain and waist increase: Sleep restriction led to an average weight gain of 0.45 kg and a 0.52 cm increase in waist circumference. Source: Clarin
• More sedentary time: Total sedentary time increased by an average of 17 minutes per day overall, and nearly 30 minutes per day in men and postmenopausal women. Source: Infobae
• Hormonal changes: Leptin levels rose, which may reflect increased fat mass or leptin resistance. Source: Lavozar

Implications and expert views

Lead author Marie-Pierre St-Onge emphasized that focusing solely on diet and exercise is "a simplistic view" and that adequate sleep should be considered a key component of weight management. Source: La Vanguardia Co-author Faris Zuraikat noted that while half a kilo may seem small, "if extrapolated to a full year, it could result in clinically significant weight gain." Source: Lavanguardia The study's limitations include a small sample size and focus on high-risk individuals Source: El Confidencial, but researchers believe the findings apply broadly. Source: El Confidencial