The effects of sustained mild sleep restriction on stress and distress among healthy adults: Findings from two randomized crossover studies.
Level 2 - randomized trial
Pooled analysis of two randomized crossover trials
PubMed 38342031 · doi:10.1016/j.sleep.2024.02.001
What was done
Researchers pooled data from two randomized crossover studies evaluating healthy adults who regularly slept 7–9 h/night in a naturalistic home setting. Participants completed two 6-week intervention phases separated by a 6-week washout: habitual sleep (HS, maintaining habitual bed and wake times) and sleep restriction (SR, delaying bedtime by 1.5 h/night while keeping habitual wake times). Sleep adherence was verified using wrist actigraphy and daily sleep diaries. Measured outcomes included perceived stress, subjective anxiety, subjective depression, rumination, and cortisol at baseline and endpoint of each phase.
What was found
Among 62 participants (mean age 36.4 ± 14.0 years, 85.5% women, 63.3% racial/ethnic minority), mean total sleep time was 7.4 ± 0.4 h/night during HS compared to 6.2 ± 0.4 h/night during SR (p < 0.001). Significantly higher perceived stress (3.6 ± 1.0, p = 0.0007) and subjective anxiety (1.1 ± 0.5, p = 0.039) were observed after SR compared to HS. Sleep condition had no significant effect on subjective depression, rumination, or cortisol.
Why it matters
This study shows that prolonged mild sleep restriction typical of daily life directly elevates perceived stress and subjective anxiety in healthy adults. It indicates that even modest sleep deficits are clinically relevant targets for mental health promotion.
Limits
The total sample size was small (n = 62) and drawn from two combined studies. Participants were overwhelmingly female (85.5%), limiting generalizability to men. The study assessed only healthy adults, leaving effects on clinical psychiatric populations unknown, and no effect was detected on physiological cortisol or depressive symptoms.
Cited by
- supports In a controlled 5-night, 4-hour sleep restriction study with identical diet and supervised conditions, cortisol levels did not significantly differ compared to adequate sleep.