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

Area of Science:

• Sleep Science
• Metabolic Health
• Obesity Research

Background:

• Insufficient sleep is linked to obesity, but the causal impact of chronic, mild sleep restriction on weight status is not fully understood.
• The influence of gender and menopausal status on this relationship requires further investigation.

Purpose of the Study:

• To investigate the effects of 6 weeks of sleep restriction (SR) on energy balance and body weight regulation.
• To assess changes in adiposity, body weight, waist circumference, and related biomarkers.

Main Methods:

• Pooled analysis of two randomized crossover trials involving 95 adults at elevated cardiometabolic risk.
• Participants underwent 6 weeks of adequate sleep (AS) and 6 weeks of SR (1.5 hours less per night), separated by a washout period.
• Measurements included MRI for adiposity, body weight, waist circumference, and energy balance biomarkers.

Main Results:

• Sleep restriction reduced sleep duration by approximately 78 minutes per night compared to adequate sleep.
• Participants experienced increases in body weight (0.45 kg), waist circumference (0.52 cm), and whole-body volume (0.56 L) during SR.
• Leptin levels increased, and sedentary time rose by over 17 minutes per day with sleep restriction.

Conclusions:

• Prolonged, moderately reduced sleep duration can contribute to weight gain.
• Weight management and cardiometabolic disease prevention strategies should integrate sleep promotion to encourage adequate sleep duration.