Outdoor physical activity and self-reported severe lifetime infections in midlife

Abstract Background Regular physical activity (PA) has been associated with lower risk of infections, and frequent nature contact with improved immune functioning. Population-based studies considering the associations between outdoor PA involving contact with nature and infections are lacking. This study examines how regular outdoor PA is associated with self-reported severe lifetime infections among urban and rural middle-aged residents. Regular outdoor PA may support exposure to nature contact and benefit immune health at population level. Methods Cross-sectional associations between outdoor PA based on self-reported frequency of different outdoor activities and occurrence of self-reported lifetime severe infections were analysed with binary logistic regression analysis among participants from the Northern Finland Birth Cohort 1966 living in urban and rural areas in midlife (N = 4472). Sex, marital status, household income, sleep duration, alcohol consumption, smoking, body mass index, moderate-to-vigorous physical activity and diet quality were adjusted for. Results In urban areas 85.5% and in rural areas 88.6% of the participants reported outdoor PA at least 12 times per month. A little over a fourth of the respondents reported having any severe lifetime infection. Participants living in urban areas who regularly engaged in outdoor PA had lower odds of reporting infections than those who engaged in outdoor PA less often (adjusted OR 0.76, 95% CI 0.60-0.96). Conclusions Living in urban areas and practicing regular outdoor PA was associated with lower risk of severe infections. Participation in outdoor activities should be encouraged, especially among urban residents. Key messages • Outdoor physical activity is a potential means of enhancing contact with nature and obtaining related health benefits. • Provision of natural areas and nature elements should be emphasized in urban planning for providing health promoting environments to all urban residents.