School Schedule Provokes to Irregularity in the Sleep- Wake Cycle

*Corresponding authors e-mail: rafaella.kaline@yahoo.com.br Introduction: Most brain and body functions are influenced by sleep quality. Sleep-wake irregularity can lead to cognitive and physical impairment, and increase the risk of pathologies development. Taking this into consideration, the aim of this work was to evaluate the sleep-wake pattern in medical students under natural conditions. Methods: All volunteers (n = 32) filled questionnaires with their personal data, and health status. The students also answered the Pittsburgh Sleep Quality Index (PSQI), the Portuguese version of the Horne and Östberg Morningness/Eveningness Questionnaire (HO), the Health and Sleep Questionnaire and Epworth sleepiness scale (ESS). Activity rhythms of nine volunteers were monitored with actigraphs set to record in a 2 min-interval for 14 days, including two weekends. During this period they filled a sleep diary. During the experiment the students had classes everyday starting at 7 a.m., except on weekends. Actigraphic analyses were performed on Actiware-Sleep, version 3.4. Results: The volunteers were 18 men e 14 women (19.69 ± 1.9 years old). Analysis of the questionnaires showed values of 48.94 ± 8.65 (HO), 6.88 ± 2.06 (PSQI) and 7.2 ± 2.85 (ESS). Data were compared between weeks and weekends using the paired t-test. Data from questionnaires were different between weekdays and weekends for bed time (p < 0.001) and get up (p < 0.001). The students went to bed and got up earlier on weekdays than on weekends. Actigraphic data showed the same differences between weekdays and weekends (p < 0.007 for bed time, and p < 0.001 for get up time). Time in bed was not different between weekdays and weekends (p > 0.31 for questionnaire data, and p > 0.38 for Actigraphic data). According to students’ reports the main reason for getting up (90.6 %) on weekdays was the need to be in the class in the morning (X2 = 66.02, p < 0.001). Conclusion: The medical students had irregular sleep-wake cycle. This irregularity may be provoked by the classes’ onset, because the students had to wake up too early on weekdays due to school schedule. Support: Capes, CNPq and FAPERN. Publication History Article published online: 16 June 2026 © 2009. Brazilian Sleep Academy. This is an open access article published by Thieme under the terms of the Creative Commons Attribution-NonDerivative-NonCommercial License, permitting copying and reproduction so long as the original work is given appropriate credit. Contents may not be used for commercial purposes, or adapted, remixed, transformed or built upon. (https://creativecommons.org/licenses/by-nc-nd/4.0/) Thieme Revinter Publicações Ltda. Rua Rego Freitas, 175, loja 1, República, São Paulo, SP, CEP 01220-010, Brazil