Objective:

To investigate the effects of sleep restriction on body weight and related metabolic factors in adults at elevated cardiometabolic risk.

Approach:

• Study Design: Pooled analysis of two randomized crossover trials involving 95 adult participants aged 20 years or older who habitually slept at least 7 hours per night.
• Intervention: Participants underwent two 6-week outpatient intervention periods: one with adequate sleep (≥7 hours) and one with sleep restriction (delayed bedtime by 1.5 hours).
• Monitoring: Sleep was monitored using wrist actigraphy and sleep diaries.
• Outcomes: Primary outcomes included body weight, waist circumference, and body composition; secondary outcomes included appetite-related hormones, sedentary behavior, physical activity, and energy expenditure.

Key Findings:

• Sleep restriction led to a mean increase of 0.45 kg in body weight and 0.52 cm in waist circumference.
• Participants engaged in 17 more minutes of sedentary behavior during the sleep restriction period.
• Higher fasting leptin concentrations were observed during sleep restriction.
• No significant differences were found in body composition or levels of certain appetite-related hormones.
• Sleep restriction was associated with a mean increase of 0.56 L in whole-body volume.

Interpretation:

Sustained moderate sleep restriction may contribute to modest weight gain among individuals at elevated cardiometabolic risk.

Limitations:

• The 6-week intervention may have been too brief to detect meaningful changes in body composition.
• The relatively small sample size limited subgroup analyses and generalizability.
• Fasting metabolic measurements did not capture hormonal changes across the full 24-hour cycle.

Conclusion:

Longer-term studies are needed to determine if changes in body weight due to sleep restriction result in measurable alterations in body composition.

Sources:

• Annals of Internal Medicine