BMI, Social Physique Anxiety, and Affective Responses to Physical Activity in Sedentary, Middle-aged Women

Abstract

0455 Women's participation in physical activity (PA) decreases with age and is lower than men's at all ages. Affective responses to PA may influence participation, but the moderators of these responses during the critical early stages of engagement in PA are poorly understood. PURPOSE: To examine the relationship of BMI and social physique anxiety (SPA) with affective responses to a graded treadmill test (GXT) and a bout of treadmill PA of self-selected (SS) intensity among healthy, sedentary, middle-aged women. METHODS: 26 women (mean age ± SD = 43.1 ± 4.7 yrs; BMI = 28.5 ± 6.1 kg•m2; VO2peak = 23.3 ± 5.4 m1•kg−1•min−1) participated in (a) GXT and (b) a 20-min treadmill PA during which they could self-select their speed (0% grade) at min 0, 5, 10, 15. The ventilatory threshold (VT) was estimated from the GXT. Affective valence (Feeling Scale; FS) and activation (Felt Arousal Scale; FAS) were assessed every min of the GXT and every 5 min of the SS. SPA was assessed with the 9-item version of the SPA Scale (SPAS; Martin, et al. 1997). RESULTS: In the early stages of GXT and SS, as intensity increased, activation increased and affective valence became more positive. Beyond 40% VO2peak, valence declined during the GXT but remained positive and virtually unchanged during the SS. SPAS and BMI were negatively correlated with valence during both sessions. Regression analyses showed that BMI accounted for 36% (P < .01) of the variance in valence at VT during the GXT and 17% (P < .01) of the variance in average valence during SS. SPA did not account for any additional variance during GXT, but accounted for 13% (P < .01) beyond BMI during SS. CONCLUSION: Sedentary women with higher BMI generally had a more negative affective valence response to PA. Furthermore, higher SPA was associated with more negative valence responses to PA of SS intensity, even after BMI was taken into account. These findings suggest that PA programs for formerly sedentary women should be designed to help allay self-presentational concerns. Supported by NIMH Grant RO3 MH069724.