Congresso Brasileiro do Sono

Página Inicial » Inscrições Científicas » Trabalhos

Dados do Trabalho


Multiple positive outcomes of delaying school starting times in adolescents


Delaying school start time (DSST) is thought to be beneficial for reducing sleep deprivation in adolescents and may promote improvements in emotion and cognition.


We tested the impact of DSST in one hour on sleep, sleepiness, mood and cognition of adolescents.


Study comprises 3 consecutive weeks, with 1 for baseline evaluation (A) with regular school starting time (7:30AM), 1 for intervention with DSST (8:30AM) (B), and a recovery week (C) with school schedule back to regular time (07:30AM). 48 (18♀) High School students (14-18 years) participated in the study. We tested: Sleep, with continuous actigraphy and the Pittsburgh Sleep Quality Index (PSQI); Sleepiness, using the Karolinska Sleepiness Scale (KSS) continuously and twice a day, and the Epworth Sleepiness Scale (ESS); Emotion, adopting 2 scales: Profile of Mood States (POMS) and Hospitalar Anxiety and Depression Scale (HADS); and Cognition, with 2 tests, the Free Recall task and N-back. Besides the continuous evaluation all other variables were collected at the end of each week. Repeated measures ANOVA were performed to compare means within the three weeks of the study. 


We found an increasing on sleep duration during the intervention week (A=7:03±0:41; B=7:35±0:48; C=6:46±0:48 p<.01), due the delaying waking up time (A=6:54±0:12; B=7:42±0:30; C=6:46±0:15; p<.01) and no changes in bedtime (A=23:18±0:42; B=23:29±0:36; C=23:28±0:41; p=0.27. Delayed school start time also reduced somnolence (KSS p<0.01; ESS p<0.01) and improved multiple aspects of mood measured by POMS: Tension (p<0.01); Depression (p<0.05); Anger (p<0.01); Vigor (p<.01); Fatigue (p<.01); Confusion (p=0.01) and Total Mood Disturbance (p<0.01). Mood measured by HADS presented improvement for the Depression subscale (p=0.04) but not for the Anxiety (p=0.10). It was possible to identify an increasing in Total Hits for one aspect of N-Back (p<0.05), however, no significant effect on memory evaluated by Free-Recall was noticed.


Starting school later was effective to improve multiple aspects of students life. Adolescents slept longer and did not change bedtime. Furthermore, positive outcomes for sleepiness, emotion and cognition were found. This study adds compelling evidence to the affirmative effects of DSST and this practice must be considered by the educational sector.


School start times; Sleep; Adolescents.




Escola de Artes, Ciências e Humanidades, Universidade de São Paulo (USP) - Sao Paulo - Brasil, Programa de Pós-Graduação em Biociências, Universidade Federal da Integração Latino Americana (UNILA) - Parana - Brasil, Universidade Federal da Fronteira do Sul (UFFS) - Parana - Brasil


Laura Bruna Gomes Araújo, Sandiéli Bianchin, Mario Pedrazzoli, Felipe Beijamini