Objective The anxiety-related insomnia and other sleep disorders were mentioned as possible side effects of quarantine and stay-at-home conditions. The questions to be explored were: Are there discernable differences in hours of sleep and sleep habits between the normal operational environment and the stay-at-home condition? and How seriously anxiety-induced insomnia or other sleep disorders may affect individuals during the stay-at-home? Methods This international prospective study analyzed results from the sleep-wake patterns questionnaire, daily logs, and interviews. During COVID-19 pandemic, surveys were administered to the healthy volunteers with stay-at-home for 14 days or more, without previous sleep disorders; volunteers were not involved in online education/work daily timetable-related activities. Results We analyzed 14,000 subjects from 11 countries with average stay-at-home of 62 days. The most significant changes in sleep occurred during the first 14 days of stay-at-home. The difference in the sleep duration between weekdays and weekends disappeared. Most of the participants discontinued using alarm clocks. The total sleep time increased in duration up to 9:10 ± 1:16 to the end of the quarantine/stay-at-home (+1:34, p = 0.02). The age-dependent changes in napping habits occurred. Only 1.8% of participants indicated insomnia during the first 14-day period with a decline to 0.5% after two months of stay-at-home. Conclusion During the stay-at-home situation, both duration and timing of sleep significantly differ from those of daily routine and most humans sleep longer than in a schedule-dependent operational environment. An appearance of anxiety-induced insomnia is extremely rare if a healthy individual is already in the stay-at-home situation.

Background The coronavirus pandemic presented a unique opportunity to study the daily temporal patterns and sleep habits of humans. The question to be explored was: Are there discernible differences in sleep between the normal operational environment and the stay-at-home condition? Methods This international prospective study analyzed results from the sleep-wake patterns questionnaire, daily logs, and interviews. Surveys were administered to the healthy volunteers (age 15–60 y) with stay-at-home for a month or more, without previous sleep disorders and mood-related complaints; volunteers were not involved in online education/work daily timetable-related activities. Results We analyzed 3787 subjects with average stay-at-home of 65 ± 9 days. The most significant changes in sleep occurred during the first ten days when the difference between weekdays and weekends disappeared and changes occurred in napping habits. The majority of the participants (66.8%) shifted toward eveningness when the self-selected sleep was possible and 1869 volunteers appeared to be owls (49.4%), 823 (21.7%) exercised “typical” sleep, 478 (12.6%) were larks, and 617 (16.3%) participants were completely desynchronized to the end of stay-at-home. In addition, 497 participants (13.1%) alternated their sleep habits. The most of the desynchronized participants (n = 414) were older than 50 years (age correlation r = 0.80), and predominantly males (n = 297, r = 0.76). Conclusion In self-selected sleep conditions, the timing of sleep and sleep habits significantly differ from those of socially and economically fixed daily routine conditions. The changes in daily temporal patterns of humans during a prolonged stay-at-home situation indicate that human sleep habits may change according to existing living conditions.

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Aim We aimed to establish a normative range of surface skin temperature (SST) changes due to blood redistribution in adolescents and to register the time needed for complete postural change-related blood redistribution. Methods The healthy volunteers (age 15–18, n = 500, M 217, F 283) were recruited for this prospective multicenter study. The volunteers were asked to keep one extremity down and another extremity up in supine rest, sitting with straight legs, and upright rest. We obtained temperature readings being taken from the tips of the middle fingers and temperature readings from the tips of the first toes at the ambient temperature of 25 °C and 30 °C. The control group consisted of a 100 of adult volunteers. Results The resting temperature of the middle fingers for a sitting participant was 28.6 ± 0.8 °C. The physiological change of this temperature during body position changes was 4.5 ± 1.1 °C and for most of the participants remained within the 26.5–31.5 °C range at 25 °C. For the toe, physiological skin temperature range was 25.5–33 °C. At 30 °C, these ranges were 27–33 °C for the fingers and 27–34 °C for the toes. On average, 2–3 min were needed for such temperature changes. Conclusion At normal room temperature, the SST of thermoneutral adolescents may vary within a range of approximately 5 °C only due to the blood redistribution in the body. This range is specific for each person due to individual peculiarities of the vasomotor activity. This normative range of SSTs should be taken into account during investigations of thermoregulation.