Adolescents Living in Homes Without Electric Lighting Have Earlier Sleep Times

Abstract

The aim of this project was to compare circadian rhythmicity of a group of 37 adolescents (14 girls), aged 11 to 16 (mean age = 13.1 ± 1.7 years), with and without electricity at home. Twenty students attended morning school (07:30–11:30), and 17 attended evening school classes (19:00–22:30). Eleven adolescents had no electric lighting at home (5 attended morning classes and 6 attended evening classes). They completed a sleep log and wore a wrist actigraph for 5 consecutive days. Saliva samples were collected to assess DLMO. Data were compared by ANOVA and showed later timing and a more extended sleep period for those who attended late classes. Those adolescents without electricity at home had significantly earlier sleep onset on school days. As to DLMO, a trend to a delay was observed in the groups who had electric lighting.

Notes

^aMain effect of school schedule, F(1, 33) = 71.24, p < .01.

^bMain effect of electricity, F(1, 33) = 4.83, p < .05.

^cMain effect of school schedule, F(1, 33) = 14.70, p < .01.

^dMain effect of school schedule, F(1, 33) = 19.87, p < .01.

^eInteraction of school schedule and electricity, F(1, 33) = 5.99, p < .05.

^fMain effect of school schedule, F(1, 33) = 5.23, p < .05.