Sleep duration during COVID-19 lockdown: systematic review and meta-analysis

In attempts to slow down the spread of COVID-19 pandemic, countries took different measures including lockdowns. Several studies reported the effects of lockdowns on sleep mostly suggesting an increase in sleep duration during lockdowns. This is an interesting outcome as life in the modern world were associated with insufficient sleep. The present study is a systematic review and meta-analysis of work regarding sleep duration during lockdowns. We searched PubMed using the terms “COVID-19”, “SARS-CoV-2”, “lockdown”, “stay at home”, “quarantine” and “sleep” and found 262 papers. After applying exclusion criteria, we identified 26 papers (with 35 discrete studies) for the meta-analysis. A fixed effect model was used with effect sizes estimated using Cohen’s d and heterogeneity of effect sizes tested using the Cochran’s Q test statistics. Most studies (31/35) report an increase in sleep duration during lockdown periods with a mean (± STD) of 31.5 ± 21.2 minutes. Effect sizes (Cohen’s d) ranged between 0.08 and 3.34, which are considered between very small and huge. Q statistics was 4859.3 (p < 0.0001) and with no indication for publication bias (Egger’s test, p = 0.45). Eight studies also reported measures of “sleep quality” with 6/8 reporting worsening of sleep quality with small to large effect sizes Cohen’s d range between 0.09 and 1.86). The study demonstrates increased sleep duration during lockdowns. Increased sleep duration is a positive change, but effects on well-being during lockdowns might be overshadowed by reduced sleep quality, increased stress, and lowered mood. It is interesting whether longer sleep duration habits may survive to post-COVID-19 days.