Social Network Negativity and Physical Activity: New Longitudinal Evidence for Young and Older Adults 2015-2018.

Purpose: Physical activity (PA) has considerable public health benefits. Positive aspects of the interpersonal environment are known to affect PA, yet few studies have investigated whether negative dimensions also influence PA. This study examines the link between changing social network negativity and PA, net of stable confounding characteristics of persons and their environments. Method: Polling respondents in the San Francisco Bay Area over three waves (2015-2018), the UCNets project provides a panel study of social networks and health for two cohorts of adults. Respondents were recruited through stratified random address sampling, and supplemental sampling was conducted through Facebook advertising and referral. With weights, the sample is approximately representative of Californians aged 21-30 and 50-70. Personal social networks were measured using multiple name-generating questions. Fixed effects ordered logistic regression models provide parameter estimates. Results: Younger adults experience significant decreases in PA when network negativity increases, while changes in other network characteristics (e.g. support, size) did not significantly predict changes in PA. No corresponding association was found for older adults. Results are net of baseline covariate levels, stable social and individual differences, and select time-varying characteristics of persons and their environments. Conclusion: Leveraging longitudinal data from two cohorts of adults, this study extends understanding on interpersonal environments and PA by considering the social costs embedded in social networks. This is the first study to investigate how changes in network negativity pattern PA change. Interventions that help young adults resolve or manage interpersonal conflicts may have the benefit of helping to promote healthy lifestyle choices.