Independent and Joint Associations of Physical Activity and Sleep on Mental Health Among a Global Sample of 200,743 Adults

BackgroundPrevious research has demonstrated that both sleep and physical activity (PA) are independently associated with various indicators of mental health among adults. However, their joint contribution to mental health has received limited attention. The present study used cross-sectional data from the Mental Health Million Project to examine the independent and joint effects of sleep and PA on mental health among a global sample of adults, and whether these effects differ among individuals receiving mental health treatment.MethodThe sample included 200,743 participants (33.1% young adults, 45.6% middle-aged adults, 21.3% older adults; 57.6% females, 0.9% other) from 213 countries, territories, and archipelagos worldwide that completed a comprehensive 47-item assessment of mental health including both problems (i.e., ill-being) and assets (i.e., well-being): the Mental Health Quotient. Participants also reported their weekly frequency of PA and adequate sleep, and mental health treatment status. A series of generalized linear mixed models were computed.ResultsIndependent dose-response associations were observed, whereby greater amounts of PA and adequate sleep were each associated with better mental health. In addition, a synergistic interaction was observed in which the positive correlation of PA with mental health was strengthened with greater frequency of adequate sleep. These benefits were less pronounced among adults receiving mental health treatment.ConclusionWhile findings suggest sleep can help to offset the negative influence of a physically inactive lifestyle (and vice versa), our results point to a “more is better” approach for both behaviors when it comes to promoting mental health.