Social anxiety moderates the relationship between body mass index and motivation to avoid exercise.

Higher weight individuals experience frequent weight-related discrimination, which is associated with exercise avoidance. Exercise is a health behavior with multiple physical and mental health benefits and should be accessible to all. The current study examined another factor that might influence exercise in addition to weight stigma: social anxiety (SA). Given the often public nature of exercise, individuals with SA may feel scrutinized when exercising, which may lead to avoidance. This study examined whether SA moderates the relationship between body mass index (BMI) and exercise and whether SA and its interaction with BMI predict exercise behavior after accounting for weight stigma. We administered an online survey to 603 undergraduates (72 % female, 60 % White). SA was not significantly associated with BMI, but it was positively associated with weight stigma and exercise-avoidance motivation and negatively associated with self-reported exercise. SA moderated the relationship between BMI and exercise-avoidance motivation; individuals with higher BMIs were motivated to avoid exercise, but only if they reported higher SA. This interaction predicted exercise-avoidance motivation after accounting for weight stigma and its interaction with BMI. However, SA did not moderate the relationship between BMI and self-reported exercise. SA may be associated with exercise avoidance among higher weight individuals.