Investigating Preferred Nap Schedules for Adolescents

The present study investigates whether a continuous stretch of night time sleep (8 hours) will lead to better neurobehavioural outcomes relative to nocturnal sleep restriction (6.5 hours) and daytime nap (1.5 hours) of the same total duration. The 15‐day protocol is conducted in a dormitory on 60 high school students, aged 15 to 19 years old. Participants are assigned to a nap or no‐nap group. Both groups start with two 9‐hour adaptation and baseline nights, followed by two successive cycles of sleep restriction (6.5‐h time in bed (TIB); 00:15‐06:45 or 8‐h TIB; 23:30‐07:30) and recovery (9‐h TIB; 23:00‐08:00). Following each sleep‐restricted night, the nap group receives a 1.5‐h nap opportunity, while participants in the no‐nap group watch a documentary. Throughout the protocol, sleep‐wake patterns are assessed with actigraphy and polysomnography. Sleepiness levels, mood, vigilance, working memory / executive functions, and speed of processing are assessed 3 times daily (10:00, 16:15, and 20:00). All participants stay in air‐conditioned, twin‐share bedrooms with en‐suite bathrooms. Bedroom windows are fitted with blackout panels to ensure participants are not woken up prematurely by sunlight. Earplugs are provided, and participants are allowed to adjust the temperature of their bedrooms to their personal comfort. Three main meals are served each day, with snacks being provided for upon request. Caffeinated drinks, unscheduled sleep, and strenuous physical activities are prohibited. Outside of scheduled sleep, meal, and cognitive testing times, participants spend the majority of their free time in a common room that is illuminated by natural and artificial lighting. They are allowed to read, play non‐physically exerting games, watch videos, and interact with research staff and other participants. Participants are under constant supervision by the research staff.