Variation in day length is proposed to impact sleep, yet it is unknown whether this is above the influence of behavioural factors. Day length, sleep hygiene, and parent-set bedtime were simultaneously explored, to investigate the relative importance of each on adolescents' sleep.
An online survey was distributed in four countries at varying latitudes/longitudes (Australia, The Netherlands, Canada, Norway).
Overall, 711 (242 male; age M = 15.7 ± 1.6, range = 12-19 yrs) adolescents contributed data. Hierarchical regression analyses showed good sleep hygiene was associated with earlier bedtime, shorter sleep latency, and longer sleep (ß = -0.34; -0.30; 0.32, p