Romdhani, MohamedAmmar, AchrafTrabelsi, KhaledChtourou, HamdiVitale, Jacopo AntoninoMasmoudi, LiwaNedelec, MathieuRae, Dale ElizabethAl-horani, Ramzi A.BEN SAAD, HelmiBragazzi, LuigiDonmez, GurhanDergaa, IsmailDRISS, TarakFarooq, AbdulazizHammouda, OmarHarroum, NesrineHassanmirzaei, BaharKhalladi, KarimKhemila, SyrineMataruna-Dos-Santos, Leonardo JoseMoussa-Chamari, ImenMujika, IñigoHelú, Hussein MuñozFashkhami, Amin NorouziPaineiras-Domingos, Laisa LianeKhaneghah, Mehrshad RahbariSaita, YoshitomoSouabni, MaherSouissi, NizarWashif, Jad AdrianWeber, JohannaZmijewski, PiotrTaylor, LeeGarbarino, SergioChamari, Karim2022-06-132022-06-132022-06-30Romdhani, M., Ammar, A., Trabelsi, K., Chtourou, H., Vitale, J. A., Masmoudi, L., . . . Chamari, K. (2022). Ramadan observance exacerbated the negative effects of COVID-19 lockdown on sleep and training behaviors: A international survey on 1,681 Muslim athletes. Frontiers in Nutrition, 9. https://doi.org/10.3389/fnut.2022.925092https://doi.org/10.3389/fnut.2022.925092http://hdl.handle.net/20.500.12519/672Objective: Disrupted sleep and training behaviors in athletes have been reported during the COVID-19 pandemic. We aimed at investigating the combined effects of Ramadan observance and COVID-19 related lockdown in Muslim athletes. Methods: From an international sample of athletes (n = 3911), 1681 Muslim athletes (from 44 countries; 25.1 ± 8.7 years, 38% females, 41% elite, 51% team sport athletes) answered a retrospective, cross-sectional questionnaire relating to their behavioral habits pre- and during- COVID-19 lockdown, including: (i) Pittsburgh sleep quality index (PSQI); (ii) insomnia severity index (ISI); (iii) bespoke questions about training, napping, and eating behaviors, and (iv) questions related to training and sleep behaviors during-lockdown and Ramadan compared to lockdown outside of Ramadan. The survey was disseminated predominately through social media, opening July 8th and closing September 30th, 2020. Results: The lockdown reduced sleep quality and increased insomnia severity (both p<0.001). Compared to non-Muslim (n=2230), Muslim athletes reported higher PSQI and ISI scores during-lockdown (both p<0.001), but not pre-lockdown (p>0.05). Muslim athletes reported longer (p<0.001; d=0.29) and later (p<0.001; d=0.14) daytime naps, and an increase in late-night meals (p<0.001; d=0.49) during- compared to pre-lockdown. Both sleep quality (χ2=222.6; p<0.001) and training volume (χ2=342.4; p<0.001) were lower during-lockdown and Ramadan compared to lockdown outside of Ramadan in the Muslims athletes. Conclusion: Muslim athletes reported lower sleep quality and higher insomnia severity during- compared to pre-lockdown, and this was exacerbated by Ramadan observance. Therefore, further attention to Muslim athletes is warranted when a circadian disrupter (e.g., lockdown) occurs during Ramadan. © 2022 Romdhani, Ammar, Trabelsi, Chtourou, Vitale, Masmoudi, Nedelec, Rae, Al-horani, BEN SAAD, Bragazzi, Donmez, Dergaa, DRISS, Farooq, Hammouda, Harroum, Hassanmirzaei, Khalladi, Khemila, Mataruna-Dos-Santos, Moussa-Chamari, Mujika, Muñoz Helú, Norouzi Fashkhami, Paineiras-Domingos, Rahbari Khaneghah, Saita, Souabni, Souissi, Washif, Weber, Zmijewski, Taylor, Garbarino and Chamari.en-USCreative Commons Attribution License (CC BY)ConfinementpandemicReligious fastingSleep-wake patterntraining loadArticle© 2022 Romdhani, Ammar, Trabelsi, Chtourou, Vitale, Masmoudi, Nedelec, Rae, Al-horani, BEN SAAD, Bragazzi, Donmez, Dergaa, DRISS, Farooq, Hammouda, Harroum, Hassanmirzaei, Khalladi, Khemila, Mataruna-Dos-Santos, Moussa-Chamari, Mujika, Muñoz Helú, Norouzi Fashkhami, Paineiras-Domingos, Rahbari Khaneghah, Saita, Souabni, Souissi, Washif, Weber, Zmijewski, Taylor, Garbarino and Chamari. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.