Extending weeknight sleep duration in late-sleeping adolescents using morning bright light on weekends: a 3-week maintenance study
Study Objectives
Our sleep extension intervention in adolescents showed that gradually shifting weekday bedtime earlier plus one weekend of morning bright light advanced circadian phase and increased weeknight sleep duration. Here, we examine at-home maintenance of these changes.
Methods
Fourteen adolescents (15.3-17.9 years; 7 female) completed a 7-week study. After usual sleep at home (2-week baseline), intervention participants (n=8) gradually advanced weekday bedtime (1h earlier than baseline during week 3; 2h earlier in week 4) and received bright light (~6000lux; 2.5h) on both mornings of the intervening weekend. During 3 maintenance weeks, intervention participants were instructed to maintain their school-day wake-up time on all days, keep their early week 4 bedtimes, except on weekends when they could go to bed up to 1h later, and get a 2.5-h light box exposure within 5 min of waking on one morning (Saturday/Sunday) of both weekends at home. Control participants (n=6) slept as usual at home and did not receive weekend bright light. DLMO was measured after the 2-week baseline, 2-week intervention, and 3-week maintenance in all participants. Actigraphic sleep/wake was collected throughout.
Results
After the 2-week intervention, DLMOs advanced more compared to control (37.0±40.0 mins vs. -14.7±16.6 mins), weekday sleep duration increased by 69.7±27.8 min and sleep onset was 103.7±14.2 mins earlier compared to baseline. After 3 maintenance weeks, intervention participants showed negligible DLMO delays (-4.9±22.9 mins); weekday fall asleep times and sleep durations also remained stable.
Conclusions
Early circadian phase and extended sleep can be maintained with at-home weekend bright light.