Exploratory Study on Chronotype, Sleep Habits and Presence of Sleepiness in Teenagers Who Study in the Mornings at a Public School Located in Bogota, Colombia

*Corresponding author e-mail; acamargos@unal.edu.co Introduction and Objective: To examine the relationship among chronotype, sleep habits and somnolence in a group of teenagers who study in the morning at a public school located in Bogota, Colombia. Methods: An exploratory study was carried out including a questionnaire that was designed in order to gather information taking into account social and demographic variables and their relationship with the sleep pattern. In order to evaluate the chronotype of the students, a Composite Morningness Scale (CSM) was applied. Furthermore, an assessment of the presence of somnolence was carried out by means of an Epworth scale of somnolence (ESE-VC). Results: 72 teenagers participated in this study (38 women-34 men) with an average age of 15.57 (between 15 and 18 years old). All of them are students at the CED JUAN LOZANO Y LOZANO Junior High school in the morning shift (the arrival time is 6:30 a.m, dismissal time 12:15 p.m). A diurnal chronotype of 30.6% was found as well as a neutral chronotype of 65.3% and a matinal or vespertine chronotype of 4.2%. It could be determinate an average of 7.32 ± 0,9 daily sleep hours. An inverse correlation was found between the CSM and the ESE-VC (P<0,05), as well as between the ESE-VC and the sleep hours (P<0,01), and also a direct correlation between the CSM and the sleep hours (P<0,01). Conclusion: a strong association was found among the chronotype, sleep hours and the presence of somnolence in teenagers who study in the morning. It is also evident that teenagers with Morningness tendencies can express themselves with extreme values barely compatible with school schedules making difficult the academic performance. 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