Annals of Internal MedicineProlonged Short Sleep and Its Effect on Body Weight and Composition: A Pooled Analysis of Randomized Trials

⚠️ Small Study / Early Comparative Evidence

A pooled analysis of randomized crossover trials found that reducing sleep by ~78 minutes nightly for 6 weeks increased body weight and waist circumference in adults at cardiometabolic risk. The findings suggest modest but measurable effects of sustained sleep restriction on energy balance, though long-term clinical impact remains uncertain.

Clinical Considerations

• Sleep restriction (−78 minutes/night) increased body weight by 0.45 kg and waist circumference by 0.52 cm over 6 weeks.
• Leptin levels increased with sleep restriction, alongside 17.2 additional minutes of sedentary time daily.
• Participants were 95 adults with ≥7-hour baseline sleep and elevated cardiometabolic risk, studied in randomized crossover design.
• Short intervention duration and modest effect sizes limit conclusions on body composition or long-term weight trajectories.

Practice Applications

• Recognize sleep duration as a contributing factor in weight management discussions
• Interpret findings as modest, short-term changes rather than definitive causal drivers
• Incorporate sleep history into cardiometabolic risk assessments
• Avoid overstating sleep extension as a primary weight-loss intervention