Effects of Sports Bras and Breast Volume on Pulmonary System and Respiratory Symptom Responses to Exercise in Healthy Females.

Purpose: This study assessed the individual and combined effects of sports bras and breast volume on pulmonary system and respiratory symptom responses to exercise in recreationally-active females.

Methods: Twenty-three healthy females (18-27 y; bra sizes 32B-36DDD) were divided into small and large breast volume groups (SBV and LBV, respectively) around median volume (324 ml; mean ± SD SBV: 284 ± 38 ml vs. LBV: 560 ± 97 ml; p < 0.001, g = 3.84). Participants completed three 5-minute bouts of constant-load cycle exercise at 30, 60, and 90% of their peak power output while wearing a high-support sports bra, low-support sports bralette, or their own (self-selected) sports bra in randomized order. Measurements included ventilation, breathing pattern, respiratory pressures, diaphragm electromyogram (EMGdi), and ratings of perceived exertion (RPE), breathlessness (intensity and unpleasantness) and chest tightness due to bra.

Results: Compared to low-support and personal sports bras, the high-support sports bra evoked stronger sensations of restricted breathing and chest tightness ('slight' to 'moderate' restriction in n = 7 [30%] vs. n = 1 [4%] in low-support and personal bras; p = 0.014). There was, however, no evidence of greater concomitant inspiratory constraints, EMGdi, or inspiratory muscle pressure generation in either bra (all p > 0.05). Notably, LBV compared to SBV participants reported greater RPE (p = 0.037, ηp2 = 0.20), breathlessness intensity (p = 0.039, ηp2 = 0.20) and unpleasantness (p = 0.041; ηp2 = 0.19), which, in the setting of comparable pulmonary system responses to exercise, was likely driven by stronger perceived chest tightness and/or bra awareness in LBV participants.

Conclusions: Despite evoking mild-to-moderately severe chest tightness due to bra during exercise - correctly fitted sports bras, whether low- or high-support, do not impose a physiological burden to the respiratory system and its response to mild-to-heavy intensity exercise in otherwise healthy females.