Kanchana Taothong. Sports bra might possibly affect cardiovascular function in active women. Master's Degree(Sports Science). Mahidol University. Mahidol University Library and Knowledge Center. : Mahidol University, 2015.
Sports bra might possibly affect cardiovascular function in active women
Abstract:
The aim of this study was to investigate the effect of sports bras on cardiovascular functions at rest, during and after exercise. Thirteen young habitual active females volunteered to complete 3 randomized running trials with different bra conditions of no bra (NB), casual bra (CB) and sports bra (SB) on a motor-drive treadmill at a constant speed of 6.5 km/h, 0% grade up to 60, 70 and 80% of age-predicted maximal heart rate (MHR). Continuous cardiovascular variables, including heart rate (HR), stroke volume (SV), cardiac output (CO), cardiac index (CI), end-diastolic volume (EDV), ejection fraction (EF), systemic vascular resistance (SVR), blood pressure (BP), blood perfusion (BPF), were collected at rest, during and after exercise. Results showed that all resting cardiac variables were not significantly different between groups. As exercise was started, all three conditions showed patterns of significant increase in heart rates (HR), stroke volume (SV), cardiac output (CO) and cardiac index (CI) from its corresponding resting values (p<0.05). Within group comparisons, SVR showed reduction at the beginning of exercise, EDV in SB and EF in NB and SB showed no significant differences from initial resting values. Between group comparisons during exercise showed no significant differences of most of the variables with the exception of differences of SV (p<0.05) and CO (p<0.05) between SB and CB at 60%MHR. No significant differences of other variables were detected at any intensity. During recovery period, there was an immediate decline, compared between 80%MHR and 1st min, in HR in all groups (p<0.05), SV in CB (p<0.05), CO and CI in NB (p<0.05) and CB (p<0.05) (Figure1A, 1B, 1C and 1D). There was reduction in EDV in CB (p<0.05). During recovery period, when compared to resting values, SV and EDV in all groups had no significant difference; HR, CI and CO showed significant difference throughout 5 min period (p<0.05). When compared between resting values and 1st min of recovery, EF in all groups showed significant difference (p<0.05); SVR had significant increased in all groups (p<0.05); SBP in all groups showed significant difference only in NB group (p<0.05); DBP in NB and CB showed significant difference (p<0.05); blood perfusion outside the strap in all groups showed no significant differences (p<0.05) and lastly blood perfusion inside the strap in all groups showed significant differences only in CB (p<0.05). In conclusion, both central and peripheral cardiac functions including rate and contractility, systolic and diastolic blood pressures and total vascular resistance exhibit similarly as when subjects were in no bra or casual bra. Thus, it is recommended from this study that sports bras can be used safely with no cardiovascular limitations.