The effects of sustained mild sleep restriction on stress and distress among healthy adults: Findings from two randomized crossover studies

Objective/background: Experimental studies suggest that sleep loss affects psychological outcomes. However, most studies focus on acute severe in-laboratory sleep restriction, with limited ecological validity. This study examines the impact of sustained mild sleep restriction (SR) on stress and distress among healthy adults in a naturalistic home environment. Patients/methods: We analyzed data from two randomized crossover studies. Individuals who regularly slept 7-9 h/night completed two 6-wk intervention phases separated by a 6-wk washout: habitual sleep (HS: maintenance of habitual bed and wake times) and SR (delayed bedtime by 1.5 h/night and maintenance of habitual wake time). Adherence to sleep duration requirements was verified with wrist actigraphy and daily sleep diaries during each intervention phase. Measures of perceived stress, subjective anxiety, subjective depression, rumination, and cortisol were collected at baseline and endpoint of each intervention phase. Results: Sixty-two participants (age 36.4 +/- 14.0 y, 85.5 % women, 63.3 % racial/ethnic minority) were included in our analyses. Mean total sleep time was 7.4 +/- 0.4 h/night during HS and 6.2 +/- 0.4 h/night during SR (p < 0.001). 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. No effect of sleep condition was observed on subjective depression, rumination, and cortisol. Conclusions: Our findings suggest that prolonged mildly insufficient sleep, similar to what commonly experienced in the real world, can lead to increased perceived stress and subjective anxiety in healthy adults. Addressing sleep loss, even if mild, should be a key component of interventions aimed at promoting mental health in the general population.