Association of morningness-eveningness preference with physical activity during the COVID-19 pandemic social distancing: a cross-sectional survey in Brazil Circadian rhythm, physical activity and isolation

Social distancing (SDIST) to contain COVID-19 pandemic spread implies reduced sunlight exposure and social daily life, which delay the circadian system and increase eveningness preference. The regular practice of physical activity (PA) is a time cue that decreased during SDIST. However, it is unknown if decreased PA may be associated with increase of eveningness preference. This study aimed to investigate if PA changes might be associated with changes in the morningness-eveningness preference of individuals practicing SDIST in Brazil. For this, 322 adults (18-89 years-old) regularly living in Brazil between March and October 2020 answered an online survey including questions considering the before and during SDIST period on PA (min/week) and morningness-eveningness questionnaire score. Sociodemographic, SDIST, anthropometric, and health characteristics were also included in the online survey. Participants self-reported an increase of eveningness preference comparing Before-SDIST with During-SDIST scores (56 +/- 12 vs. 52 +/- 13, p < .0001). Self-reported PA decreased comparing Before-SDIST with During-SDIST (230 +/- 170 vs. 149 +/- 155 min/week, p < .0001). Decrease in the total volume of PA and hours spent outside per day, and higher body mass index were associated with the increase in eveningness preference (R-2 = .077), although the decrease in the total volume of PA was the strongest association (R-2 = .037). In summary, our results show that SDIST may cause a delay in the circadian system, which is associated with the decrease of PA, a reduction in the hours spent outside per day with sunlight exposure, and obesity.