Understanding and Changing Social Physique Anxiety Among Women: Examining the Role of Cortisol and Exercise

The general purpose of this dissertation was to use a psychobiological approach to examine the psychosocial, biological and behavioural factors associated with social physique anxiety (SPA) in women. With this perspective in mind, the broad objectives of the present dissertation were as follows: (1) to examine the relationship between social physique anxiety and cortisol, (2) to implement an exercise intervention to change social physique anxiety and cortisol, and (3) to understand the mechanisms responsible for exercise-induced changes in social physique anxiety.;In Study 2, a controlled experimental design was used to compare the effects of an 8week exercise (aerobic versus resistance) training intervention on changes in SPA and changes in cortisol. In addition, this study examined the physical and psychosocial mechanisms underlying the effects of exercise training on SPA and explored the possible protective effects of exercise training on state SPA and cortisol responses to an acute physique evaluative threat situation. Forty six women were randomly assigned to one of two exercise conditions: aerobic or resistance training. Analyses indicated that the aerobic condition experienced greater improvements in trait SPA than the resistance training condition and both groups exhibited significant decreases in cortisol levels (compared to baseline). In addition, changes in aerobic self-efficacy and perceived physical endurance partially mediated the effect of the exercise intervention on trait SPA. Finally, the results demonstrated that 8-weeks of exercise training (regardless of mode) may buffer the state SPA response to a physique evaluative threat manipulation.;In summary, these studies provide a broader understanding of the factors associated with SPA. The results demonstrated that for women, situations that elicit physique evaluative threat elicit concomitant changes in cortisol. Exercise training is an effective strategy for improving SPA, reducing cortisol responses, and possibly providing a protective effect against the state SPA response among young women. Aerobic exercise training is more effective for improving SPA than resistance training and this is' due in part to increases in aerobic self-efficacy and perceived physical endurance. The dissertation studies provide momentum for extending the scope of research on SPA and for determining the best approach for improving SPA among women.;Specifically, in Study 1, the purpose was to experimentally manipulate physique evaluative threat in a controlled laboratory setting to determine if physique evaluative threat (i.e., social physique anxiety; SPA) produces concomitant changes in cortisol secretion. Additionally, this study examined if perceptions of physique evaluative threat were related to cortisol responses. Participants were 50 women who were randomly assigned to an experimental, or a control condition. Results indicated that post-manipulation, the experimental condition had higher cortisol levels than the control condition. Furthermore, regression analyses indicated that a post-manipulation measure of physique evaluative threat explained 7.2% of the variance in post-manipulation cortisol levels. Taken together, these findings suggest that acute changes in physique evaluative threat cause changes in cortisol levels and provide an empirical basis for studying cortisol's role in body image disturbance and related pathologies (e.g., eating disorders).