key: cord-0794962-332x838j
authors: Raman, Sudha; Coogan, Andrew N.
title: Effects of Societal-Level COVID-19 Mitigation Measures on the Timing and Quality of Sleep in Ireland
date: 2021-02-15
journal: Sleep Med
DOI: 10.1016/j.sleep.2021.02.024
sha: d9890cc1f4e3f9ba980be17ce19e5d9d1ac765b7
doc_id: 794962
cord_uid: 332x838j

OBJECTIVES: Under usual circumstances, sleep timing is strongly influenced by societal imperatives. The sweeping whole-of-society measures introduced in response to the COVID-19 pandemic may represent a unique opportunity to examine the impact of large-scale changes in work practices on sleep timing. As such, we examined the impact of the travel restrictions and work from home orders imposed in Ireland in March 2020 on sleep timing and quality. METHODS: We utilized a cross-sectional survey deployed shortly after the imposition of restrictions which assessed current and retrospective ratings of sleep timing and quality; the final response set analysed was from 797 adults. Participants completed the ultra-short Munich Chronotype Questionnaire, the Pittsburg Sleep Quality Index, and answered questions pertaining to work status such as working from home during the period of restrictions. RESULTS AND CONCLUSION: There was a significant shift to later sleep start and end times, as well as delayed time of midsleep on both work and free days, during the period of restrictions. Sleep duration was longer for work days, while free day sleep duration was shorter and there was a reduction in social jetlag during the restrictions. Those who worked from home during restrictions had longer sleep duration on work day and had a significantly larger difference in sleep end on work day than “essential” workers who continued to attend their normal place of work.

797 adults. Participants completed the ultra-short Munich Chronotype Questionnaire, the Pittsburg Sleep Quality 48 Index, and answered questions pertaining to work status such as working from home during the period of 49 restrictions. Results and conclusion: There was a significant shift to later sleep start and end times, as well as 50 delayed time of midsleep on both work and free days, during the period of restrictions. Sleep duration was 51 longer for work days, while free day sleep duration was shorter and there was a reduction in social jetlag during

Following the establishment of community transmission of the SARS-CoV2 virus and increasing rates of 60 the disease COVID-19 in Ireland, on March 12 th 2020 the Government of Ireland announced the implementation and were augmented on the 27 th March 2020 with the introduction of more radical "stay-at-home" measures, requiring home working except for designated key workers and the suspension of all non-essential travel (Government of Ireland, n.d.) . These measures remained in force until May 5 th 2020 when a phased relaxation 66 of restrictions was initiated. Various data indicate that social and travel restrictions implemented in response to 67 COVID-19 resulted in a remarkable decrease of human mobility across the globe (Bonaccorsi et al., 2020;  68 Hadjidemetriou et al., 2020) . For the vast majority of non-essential workers in Ireland, travel restrictions 69 resulted in a requirement to work from home, and students were tutored at home by their care-givers and/or 70 virtual tuition. As such, commuting was not required for the majority of workers and students, and there may 71 have been an increase in flexibility for scheduled work and study duties throughout the day; clearly, there are 72 potential implications for the timing and quality of sleep that may arise from such radical re-arrangements of 73 daily schedules.

Under usual circumstances, almost 80% of participants in Europe reported using an alarm clock on 75 workdays (Roenneberg et al., 2012) , indicating widespread sleep loss resulting from the conflict between the 76 circadian clock (the endogenous near 24 hour timekeeping system that imposes a temporal architecture on 77 physiology and partially dictates sleep time) and socially-required waking times to meet school or work 78 obligations. This conflict between internal biological time and social schedules is termed social jetlag, and is 79 formally described as the discrepancy in the timing of midsleep (the midpoint between sleep start and 80 wakening) between work and free days (Roenneberg et al., 2019) . The timing of midsleep on free days, when 81 corrected for sleep debt accumulated during work days, is believed to indicate the phase of entrainment of the 82 circadian clock (the timing of a circadian event relative to the 24-hour day; Roenneberg et al, 2007) . As such, 83 midsleep on "free" days may be used as an indicator of chronotype (individuals' tendency towards earlier or 84 later sleep/wake cycles), as inter-individual difference in circadian processes manifest themselves in sleep/wake 85 timing differences (Adan et al., 2012; Roenneberg & Merrow, 2007) . School and work schedules tend to be early 86 in industrialised societies leading to greater conflict and discrepancy between work and free day sleep for those 87 with a predisposition for later sleep start and wake times (Raman & Coogan 2019b) .

The radical societal-level mitigation measures introduced in Ireland and other countries during the 89 COVID-19 pandemic represents a unique "natural experiment" through which to examine the effects of work 90 schedules on the timing of sleep/wake activity. In the current study we sought to examine these effects by 91 assessing sleep/wake timings before and during restrictions, the relationship between changes in key sleep 92 parameters following imposition of the restrictions and the impact of essential worker status during restrictions on sleep timing and duration.

As part of a study examining attitudes to the transition into daylight savings time, we had intended to assess sleep/wake timing and sleep quality briefly after the transition to Irish summer time (29 th March, 2020).

were characterized as before and during "lockdown" in the survey). Adults resident in Ireland were invited to 101 take part in an on-line survey, via the Qualtrics survey platform (an on-line research services provider, 102 www.qualtrics.com). The survey went online on 11 th April 2020 and concluded on 4 th June 2020 (when travel was still restricted to within five kilometers and non-essential workers and students were still required to work 104 and study from home). Recruitment was via the Brainstorm blog of the national broadcaster (Radio Television 105 Eireann), personal contacts, social media posts, and recruitment via Qualtrics research services. Ethical approval 106 was granted by the Research Ethics Committee of Maynooth University and informed consent was indicated by 107 all participants whose data was included in the analysis.

The ultra-short version of the Munich Chronotype Questionnaire (µMCTQ; Ghotbi et al.,2020) was used 110 to assess sleep/wake timing and calculate midsleep timings and social jetlag. The µMCTQ was modified so that 111 participants were asked to indicate their sleep and wake time for work day and free day before and during 112 restrictions. Social jetlag was calculated as the absolute difference between midsleep on work day and free day,

both before and during restrictions. A"free" day is any day when sleep start (the night before the free day) and 114 sleep end (in the morning of the free day) times are not dictated by work or school commitments and time 115 schedules. As per standard protocol for calculating mid-sleep values for free days, a sleep correction was 116 applied to free day midsleep timing (MSFsc) for participants who had longer sleep duration on free day; these 117 participants slept longer on free day to compensate for sleep debt accumulated over the week, which was 118 adjusted for to reflect their true free day midsleep timing as accurately as possible ((MSFsc=MSF-(SDf-

SDweek)/2); Roenneberg & Merrow, 2007) . Key sleep parameters, such as sleep start and end and duration 120 were also calculated for both before and during restrictions. To recognise the potential reduction in accuracy 121 associated with retrospective application of the µMCTQ for self-reporting of sleep sleep/wake timings before restrictions, we rounded the timings up or down to the nearest 15-minutes intervals, and for consistency the 123 same rounding was applied to the timings reported for during restrictions. The Pittsburgh Sleep Quality Index 124 (Buysse et al., 1989) was also administered to assess sleep quality during restrictions, but for the brevity of 125 survey, participants were not asked to complete the PSQI retrospectively. Instead we requested participants to 126 rate their sleep quality before and during restrictions with two questions, on a simple single item scale of zero 127 to ten, with higher scores indicating better sleep. Further demographic information was also obtained, including period of restrictions.

debt before and during restrictions, depending on whether the dependent variable was normally distributed.

Chi-square tests for independence were used for relationships between categorical variables. Correlation 

. 

Similarly, on free day, there was a decrease in number of participants with early mid-sleep between 2am-4am,

but there was an increase in mid-sleep between 4am-6am and after 6am (p<0.001). Notably the percentage of 161 participants reporting no social jetlag increased from 18% before restrictions to 45% during restrictions 162 (p<0.001). The proportion of participants who reported using an alarm clock on work day fell from 80% before 163 restrictions to 38% during restrictions (p<0.001).

During restrictions, work day sleep timing shifted closer to sleep timing on free days, resulting in a 165 number of changes in key sleep parameters and impacting sleep debt and social jetlag ( Participants were asked to rate their sleep quality before and during restrictions on a one to ten scale,

with higher scores indicating better sleep quality. This rating declined after the imposition of restrictions 203 (6.87+0.07 to 5.69+0.09, p<0.001, Table 2 and Figure 1F ). Further, the number of participants categorized 204 according to a sleep quality score of 5 or less increased from 22% to 49% during restrictions ( essential workers compared to those who were working from home. There were no significant differences 226 between essential and non-essential workers in the changes in sleep start or end times or sleep duration on 227 free days.

changes to sleep timing on work days could reduce social jetlag. Our study, along with other sleep studies 232 conducted during the first wave of the COVID-19 pandemic (Blume et al., 2020; Wright et al., 2020) financial worries (Brooks et al., 2020; Taha et al., 2014) . Similarly, during the COVID-19 pandemic high 248 prevalence of anxiety and worries have been noted (Jungmann & Withhof, 2020; Lades et al., 2020) . Given the 249 intimate relationship between sleep quality and affect (Konjarski et al., 2018) , it is therefore not surprising that 250 potential benefits from the reduction of social jetlag does not translate into increases in subjective sleep quality.

Further, a recent study from our group recently reported only weak association between social jetlag and 252 subjective sleep quality in a normative population (Raman & Coogan, 2019a) . However, we did not record 253 affective status in the current study, and as such we cannot directly test the relationships between changes in 254 sleep timing, sleep quality and affect.

Clearly the impact of the COVID-19 restrictions on sleep behaviors may not be homogenous across the 256 population and may be moderated by factors such as household composition and family structure, 257 socioeconomic status, age and caregiving duties (Usher et al., 2020) . In our study, we specifically examined one 258 important such variable, the requirement to continue to attend one's normal place of work rather than working 259 from home. Such essential workers included those working in healthcare and those working in essential retail 260 services and accounted for 17% of the study population. As expected, these essential workers experienced less 261 changes to their sleep timing and a significantly smaller reduction in social jetlag compared to those workers 262 who were required to work from home. This finding further reinforces the importance of working and 263 commuting schedules for determining sleep timing in our society.

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