Is physical activity in natural environments better for mental health than physical activity in other environments?

Experimental evidence suggests that there may be synergy between the psychological benefits of physical activity, and the restorative effects of contact with a natural environment; physical activity in a natural environment might produce greater mental health benefits than physical activity elsewhere. However, such experiments are typically short-term and, by definition, artificially control the participant types, physical activity and contact with nature. This observational study asked whether such effects can be detected in everyday settings at a population level. It used data from the Scottish Health Survey 2008, describing all environments in which respondents were physically active. Associations were sought between use of each environment, and then use of environments grouped as natural or non-natural, and the risk of poor mental health (measured by the General Health Questionnaire (GHQ)) and level of wellbeing (measured by the Warwick Edinburgh Mental health and Wellbeing Score (WEMWBS). Results showed an independent association between regular use of natural environments and a lower risk of poor mental health, but not for activity in other types of environment. For example, the odds of poor mental health (GHQ ≥ 4) among those regularly using woods or forests for physical activity were 0.557 (95% CI 0.323-0.962), compared to non-users. However, regular use of natural environments was not clearly associated with greater wellbeing, whilst regular use of non-natural environments was. The study concludes that physical activity in natural environments is associated with a reduction in the risk of poor mental health to a greater extent than physical activity in other environments, but also that activity in different types of environment may promote different kinds of positive psychological response. Access to natural environments for physical activity should be protected and promoted as a contribution to protecting and improving population mental health.