LAUSR

Many individuals do not meet physical activity (PA) guidelines, and individuals with asthma report even lower PA levels. In healthy individuals, affective responses to PA have been shown to impact PA levels. Furthermore, several studies show that exercise-related fear-avoidance beliefs (beliefs that exercise may result in negative outcomes and should therefore be avoided) predict PA levels as well as clinical outcomes in a variety of chronic conditions. In this study, we investigated the association between exercise beliefs and self-reported PA in 1004 young adults (n=65 with self-reported asthma diagnosis). Participants reported expectations of positive and negative affective responses to exercise (measured using exercise vignettes), and exercise fear-avoidance beliefs. Participants with asthma reported increased fear-avoidance beliefs (FA) compared to participants without asthma; difference= 2.42 [95%CI 1.07-4.55]. Expectations about positive (PE) and negative (NE) affective responses to exercise were associated with self-reported time spent in vigorous PA (1SD increase in PE: 27% [95CI 8-48%] increase in vigorous PA, 1SD increase in NE: 19% [95% CI 6-31%] reduction in vigorous PA). Effects of NE were mediated by fear-avoidance beliefs (1SD increase in FA resulting in a 24% [95CI 12-35%] reduction in vigorous PA). Our findings suggest that negative expectations and fear-avoidance beliefs could explain avoidance of vigorous physical activity. Targeting fear-avoidance beliefs and increasing positive expectations may help improving physical activity levels, especially in individuals with respiratory conditions.