International Journal of Research in Medical Sciences | September 2022 | Vol 10 | Issue 9 Page 1858 International Journal of Research in Medical Sciences Chahine KR et al. Int J Res Med Sci. 2022 Sep;10(9):1858-1864 www.msjonline.org pISSN 2320-6071 | eISSN 2320-6012 Original Research Article Morning exercise improves sleep quality in university students Krystel R. Chahine 1 , Nathalie R. Chahine 2 *, Moni Nader 3 INTRODUCTION One third of human’s life is consumed by sleeping due to its importance in maintaining the body’s homeostasis particularly the regenerative aspect. This is also essential for mind reset in order to drive better performance during the diurnal activities. 1 Nowadays, the importance of sleep has been ignored and replaced by nightlife styles, thus accumulating a debt of sleep which translates into elaborate stress and unhealthy life. During the course of 50 years, a total of 1.5 hours of sleep time is being lost on average. 2 For instance, 45% of individuals aged 25-45 years lack the adequate time for sleep; a serious misfortune exposing them to various health issues. 3 Moreover, it is becoming more evident that sleep disorders are increasingly afflicting humans due to the current COVID-19 lockdowns and its imposed mobility restrictions. 4-6 Typically, a night’s sleep has four stages: falling asleep, light sleep, deep sleep and rapid eye movement (REM) sleep, which is being the most important step for 1 Department of Endocrinology, Faculty of Medical Sciences, Centre Hospitalier Universitaire (CHU), Carémeau, Nîmes, France 2 Faculty of Public Health, Lebanese University, Lebanon 3 Department of Physiology and Immunology, College of Medicine and Health Sciences, Khalifa University, United Arab Emirates Received: 06 July 2022 Revised: 31 July 2022 Accepted: 08 August 2022 *Correspondence: Dr. Nathalie R. Chahine, E-mail: nathaliechahine@hotmail.com Copyright: © the author(s), publisher and licensee Medip Academy. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT Background: Although sleep is influenced by exercise, a proper management of physical activity’s time promotes the quality of sleep. The objective of this study was to evaluate, in university students, the effect of morning or evening physical exercise on sleep pattern, along with the dynamics of hormones controlling sleep quality. Methods: We recruited 92 healthy sedentary adolescents, 18-20 year-old, poor sleepers, with normal anthropometric characteristics and no musculoskeletal or neurological problems. They were randomly distributed into 3 groups: 34 subjects practicing morning physical activity, 28 subjects practicing evening physical activity, and 30 subjects remained sedentary. The quality of their sleep was assessed using the Spiegel validated questionnaire. Body temperature was recorded in the morning and evening, and saliva samples were collected. Saliva cortisol and melatonin levels were evaluated by ELISA. Results: The group practicing exercise in the morning experienced a better quality of sleep (71.4%) versus the one exercising in the evening (44.1%, p<0.05). In parallel, the levels of melatonin and cortisol significantly increased, at night and morning simultaneously, in participants exercising in the morning. Moreover, body temperature significantly decreased in participants that exercised in the morning compared to those who practiced evening exercise, or maintained a sedentary lifestyle (p<0.05). Conclusions: Our data indicate that morning physical activity exerts a positive impact on the sleep quality, probably by decreasing cortisol and increasing melatonin levels in the evening. We presume that morning activity may efficiently reduce the burden of sleep disorders, particularly those caused by COVID-19 lockdown. Keywords: Adolescents, Cortisol, Melatonin, Physical activity, Sleep quality DOI: https://dx.doi.org/10.18203/2320-6012.ijrms20222259