A retrospective observational study found that many US federal holidays and holiday eves were associated with changes in sleep duration, decreases in sleep consistency, and later sleep onset and offset.
Data for this study were collected from subscribers to the biometric device platform of WHOOP, Inc., which is located in Boston, Massachusetts. The study interval lasted for 1 year from May 1, 2020, to May 1, 2021. WHOOP users were able to record their sleep-wake data with continuous monitoring from the device with optional daily surveys on health behaviors.
All participants were from the United States to avoid potential confounders. Those without sleep-wake data on any of the public holidays were excluded and individual sleep episodes that didn’t have complete data were not included in the final analysis. Participants were included if they were a US-based member of WHOOP who had data from 255 days or more and were aged 18 to 65 years for the data collection interval.
Included holidays in this analysis were Memorial Day, Independence Day, Labor Day, Columbus Day/Indigenous Peoples’ Day, Veterans Day, Thanksgiving Day, Christmas, New Year’s Day, Martin Luther King Jr Day, and Presidents’ Day. The days in which the clocks were set earlier and later by 1 hour in the fall and spring respectively were also included. The days before each holiday were analyzed separately.
There were 24,250 participants included in this study with 13,904 participants included in the subsample with data on alcohol use. Participants had a mean (SD) age of 37.6 (9.8) years and were primarily male (74.5%). Participants with sufficient data on alcohol use had an average age of 37.8 (9.7) years.
The mean absolute change from baseline sleep duration during federal holidays was 1.9% and the absolute change was 2.1%; 15 of the 20 holidays and eves were associated with increases in average sleep duration, with an average increase of 2.5%. There were also decreases in sleep duration in 2 of the 20 holidays, with an average decrease of 1.4%.
The largest average increases from baseline sleep duration happened on Thanksgiving Day (5.2% [0.3]), Christmas Day (5.1% [0.3]), the fall daylight savings transition (4.9% [0.3]), and New Year’s Day (4.8% [0.3]). The largest decreases from baseline sleep happened on New Year’s Eve (–2.5% [0.3]) and spring daylight savings transition (–0.8% [0.3]). Memorial Day was the only other holiday to see a decrease in sleep duration.
The mean absolute change from baseline sleep consistency was 2.1% with the absolute change of 2.8 when including the day before the holiday. There were 9 holidays and eves that were associated with a decrease in sleep consistency that had an average decrease of 4.2%. The 4 with the largest changes were New Year’s Eve (–13.8% [0.3]), New Year’s Day (–6.3% [0.3]), fall change in daylight savings (–6.1% [0.3]), and Christmas Eve (–5.0% [0.3]). The night before Labor day had the highest increase in sleep consistency (2.6%).
The mean absolute change from baseline in sleep onset was 11.8 mins with 12 of 20 holidays seeing delays in sleep onset. The largest average delay in sleep onset was on New Year’s Eve (88.9 [3.2] mins), with the spring and fall daylight savings days also having later sleep onset. The holidays with earlier sleep onset on average were Monday holidays.
The mean absolute change of sleep offset on federal holidays 21.5 mins, which was nearly twice the average change of sleep onset timing. Spring and fall daylight savings were associated with delayed sleep offset and New Year’s Eve had 78.1 (3.1) min sleep offset timing.
There were some limitations to this study. Selection bias could have amplified the Big Data Paradox and potential effects of the COVID-19 pandemic. The user base of WHOOP could be more informed about sleep and its impact on their health than the general population. The extent of the study sample’s representation of the United States is unknown, due to lack of demographic information. The study interval also occurred during the COVID-19 pandemic which may have affected the results.
The researchers concluded that changes in sleep duration, sleep consistency, and sleep timing occurred during federal holidays and their eves as well as daylight savings transitions throughout the year.
Heacock RM, Capodilupo ER, Czeisler ME, et al. Sleep and alcohol use patterns during federal holidays and daylight saving time transitions in the United States. Front Physiol. Published online July 11, 2022. doi:10.3389/fphys.2022.884154