"Many studies have examined how the 2019 Coronavirus Disease (COVID-19) has impacted sleep health. Early evidence suggests that lockdown policies worldwide have led to changes in sleep timing, duration, and quality 1,2,3,4.; however, few studies have attempted to look at the longer-term effects across multiple countries in a large data set.
This study uses self-reported data from 64,858 users of the Sleep As Android smartphone application from around the world over a 24-month period in 2019 to 2020. We found a significant but modest increase in time in bed (TIB), as well as a significant delay in sleep timing that was especially prominent on weekdays.
Our findings suggest that pandemic-induced changes in lifestyle, such as remote work and lockdown policies, may have facilitated later sleep timing but that these changes may diminish as restrictions are lifted.
While studies have identified that some people experienced shortened sleep durations 4,8, there is ample evidence that sleep duration has increased during the pandemic for a substantial proportion of the population, especially after more countries enacted lockdown policies 2,3,17.
Several studies have found decreases in sleep quality, especially in healthcare and frontline essential workers who report experiencing increased insomnia and stress 5,6,7,8,9,10,11. This effect was especially pronounced early in the pandemic among the general population as well 1,4,12,13,14,15. Indeed, we found that in the U.S., Google searches for “insomnia” increased by 58% in March through May 2020 compared to the same time frame in the previous three years 16, suggesting that sleep problems may have increased in the general population during the early months of the pandemic.
In an online survey of 7,517 respondents in 40 countries between April 4th–May 6th, 2020, average sleep duration was found to increase by 26 min on work days 17. Similarly, surveys of roughly 1000 participants in Argentina 3 and Italy 18 found that average sleep duration in non-healthcare workers increased during the pandemic.
Studies across multiple countries and in different subject populations have consistently found that people shifted their sleep timing later, perhaps because of the increased prevalence of remote work and school during the lockdown 2,3,17,19.
Studies across multiple countries and in different subject populations have consistently found that people shifted their sleep timing later, perhaps because of the increased prevalence of remote work and school during the lockdown 2,3,17,19.
Studies in university students 1,2 found that sleep times were delayed by 25–50 min on average. Studies of the general population report similar delays especially on week days 4,20,21,22, suggesting that social work schedules may be better aligned with internal chronotype during the pandemic 17.
Social jetlag, the discrepancy between people’s sleep timing on work days and free days (typically weekdays and weekends, respectively), is a well-known phenomenon 23.
In general, people report going to bed and waking earlier on weekdays compared to weekends. During the pandemic however, multiple studies found that social jetlag decreased—in other words, differences in week day and weekend sleep timing diminished, predominantly because of a delay in week day wake times 1,2,3,17.
Global changes in sleep duration and timing between 2019 and 2020. Worldwide average time in bed
Worldwide average time in bed (a) and midpoint of sleep (b) were calculated from self-reported bedtimes (c) and waketimes (d) for each quarter in 2019 (blue) and 2020 (red). Bonferroni-adjusted p values for comparisons between each quarter of 2019 to the corresponding quarter of 2020 are indicated as follows: *p < 0.05, **p < 0.01, ***p < 0.001. Means ± SEM are shown.
Changes in sleep duration and timing between 2019 and 2020 in 20 representative countries
full size image :https://www.nature.com/articles/s41598-022-14782-x/figures/2
Self-reported time in bed from 20 countries in year 2019 and 2020. Average time in bed (TIB) was calculated from self-reported bed and wake times for each day in 2019 (blue) and 2020 (red) for each country. Bonferroni-adjusted p values comparing average TIB in each quarter of 2019 to the corresponding quarter of 2020 are indicated as follows: *p < 0.05, **p < 0.01, ***p < 0.001. Bonferroni-adjusted p values comparing overall TIB in 2019 to 2020 is indicated next to each country name as follows: †p < 0.05, ††p < 0.01, †††p < 0.001. Means ± SEM are shown.
Changes in sleep timing were more widespread, with 17 countries out of 20 showing a significant delay in MOS (p < 0.05 for all), 19 countries showing a significant delay in bedtimes (p < 0.05 for all), and 16 countries showing a significant delay in waketimes (p < 0.05 for all) in 2020 compared to 2019. Only South Korea showed no change in any of the three sleep timing measures. Additionally, Japan showed no change in MOS or waketime, and Sweden and New Zealand showed no change in waketime.
Changes in sleep duration and timing between 2019 and 2020 in the United States
Self-reported sleep duration and timing in the United States during the years 2019 and 2020. Average time in bed (a) and midpoint of sleep (b) were calculated from self-reported bedtimes (c) and waketimes (d) for each month in 2019 (blue) and 2020 (red) in the United States. Bonferroni-adjusted p values for comparisons between each month of 2019 to the corresponding month of 2020 are indicated as follows: *p < 0.05, **p < 0.01, ***p < 0.001. Means ± SEM are shown.
Waketime was significantly delayed in 2020 compared to 2019 only during the months of April and May (p = 0.006 for both), by approximately 35 min. Our results suggest that in the United States, the pandemic caused shifts primarily in the timing of sleep.
Waketime was significantly delayed in 2020 compared to 2019 only during the months of April and May (p = 0.006 for both), by approximately 35 min. Our results suggest that in the United States, the pandemic caused shifts primarily in the timing of sleep.
Full article link is below.
Source:
Yuan, R.K., Zitting, KM., Maskati, L. et al. Increased sleep duration and delayed sleep timing during the COVID-19 pandemic. Sci Rep 12, 10937 (2022). https://doi.org/10.1038/s41598-022-14782-x
Yuan, R.K., Zitting, KM., Maskati, L. et al. Increased sleep duration and delayed sleep timing during the COVID-19 pandemic. Sci Rep 12, 10937 (2022). https://doi.org/10.1038/s41598-022-14782-x
2nd image Photo by cottonbro: https://www.pexels.com/photo/photo-of-a-person-sitting-on-the-floor-with-her-hands-on-her-head-6951513/
