A systematic review and meta-analysis to assess the relationship between sleep duration/quality, mental toughness and resilience amongst healthy individuals.

The majority of sleep research has focused on deleterious health outcomes, with little attention to positive sequels. A systematic review of the literature regarding sleep duration and/or sleep quality in relation to mental toughness and resilience amongst non-clinical, healthy populations was completed. Eight databases and selected sources for grey literature were searched from their inception to April 2021. A total of 1925 unique records (1898 from the database search and 27 from grey sources) were identified and screened against the pre-set inclusion and exclusion criteria. Of these, 68 studies were eligible and 63 were included in the meta-analysis. Pooled results indicated a weak, positive correlation between sleep duration and resilience (r = 0.11, p < 0.001), and sleep quality (r = 0.27, p < 0.001). The pooled correlation was slightly attenuated for prospective studies pertaining to sleep quality and resilience (r = 0.18, p < 0.001). We found evidence of high publication bias for studies that explored the relationship between sleep quality and resilience. Sleep and resilience are positively correlated but additional research is needed to verify the direct relationship through carefully designed, prospective studies that capture both subjective and objective sleep estimates. For a more comprehensive understanding, complementary reviews that explore the sleep-resilience association are needed for clinical populations, and those who have suffered extreme hardship.