Changes in sleep patterns of college students in Israel during COVID-19 lockdown, a sleep diaries study.

To prevent and reduce the spread of COVID-19, governments around the world apply social restrictions and lockdowns. Such lockdowns significantly alter daily routine and habits. A growing body of research indicates that lockdowns affect sleep and circadian rhythms. The current study further explores this effect using sleep logs for a relatively long duration including lockdown and post-lockdown periods in Israel. For two consecutive months, both during lockdown and during post-lockdown periods, from March 13th, 2020 to May 12th, 2020, Israeli students were asked to fill out daily sleep logs in which they report their sleep and wake times. The participants were also asked to fill out the Morningness-Eveningness Questionnaire (MEQ) in the beginning of the study. Data show increase in sleep duration and a delayed midsleep point during lockdown, compared to post-lockdown periods, both on workdays and on weekends. An interaction between chronotype and lockdown was also observed; morning types sleep more both during lockdown and during post-lockdown periods. Interestingly, the midsleep point of late chronotypes is later during both workdays and weekends even during lockdown when social constrains on sleep time are in part removed. Overall, the current results based on detailed and relatively long-term sleep logs analysis confirm previous work using limited measures, such as one-time questionnaires. A lockdown period affects sleep-wake behavior: during lockdown people sleep duration is increased and their sleep onset is delayed. Nevertheless, the circadian preference of individuals is conserved across conditions.