ABSTRACT
Objectives/Introduction: Sleep regulation in humans is tightly linked to social time pressure (STP) that assigns local time to meals, work, family time, and additional daily activities. The impact of the STP decrease on daily rest-activity cycles during COVID-19-mandated social restrictions (SR) has been studied epidemiologically by our and other research groups. These studies consistently showed that nocturnal sleep duration (SD) increased, social jetlag (SJL) decreased, and mid-sleep times on free days (MST, a proxy for chronotype) delayed during SRs. Here, we investigated in the Global Chrono Corona Survey (GCCS) dataset changes in the interrelationships between the temporal organization of daily sleep-wake and fasting parameters under regular, strict (before the SRs) and relaxed (during SR) STP in the general population. Method(s): The GCCS was conducted during the first wave of SRs between April 4 and May 6, 2020 in 40 countries. The final sample consisted of 7,517 respondents (68.2% females), who did not contract COVID-19 virus, and had been on average 32.7 +/- 9.1 days under SRs. Daily eating patterns were quantified in terms of fasting duration from the last to the first meal (FD) and its timing represented by the midfasting time (MFT). To assess the magnitude of fasting and sleep cycles (mis)alignment, we introduced two new factors: The difference in fasting and sleep duration (DELTAFDSD) and the difference between the two midpoints (DELTAMFMS). Result(s): Before SRs, sleep and fasting parameters showed multiple robust correlations, both in their timing (rho = 0.45), and their duration (rho = 0.25). DELTAMFMS correlated negatively with MST (chronotype), indicating that the later chronotype the larger fasting-sleep misalignment. DELTAMFMS correlated also with the SJL (rho = -0.47). During SRs, FD became longer by 41 min, mainly driven by later breakfast times. SD increased on average by 15 min. Mean DELTAFDSD increased by 15 min, while DELTAMFMS remained unchanged. The correlation between MST and MFT was substantially strengthened (rho = 0.65);MST became correlated with FD (rho = 0.21). Conclusion(s): During weeks-long reduced social time pressure, induced by social restrictions, sleep and fasting parameters became more tightly linked. Relaxed STP may promote co-alignment of daily fasting and sleep cycles and benefit overall health.