This study aimed to investigate the relationship between respiratory muscle strength and body fat percentage in women and to assess the predictive impact of these variables on overall fitness.
A cross-sectional study design was conducted, involving 63 women divided into two groups based on their body fat percentages: normal fat (NF, n=33) and higher fat (HF, n=30). Participants were recruited using non-probability convenience sampling. Body composition, including body mass index and body fat percentage, was measured through bioelectrical impedance analysis. Respiratory muscle strength was assessed using a MicroRPM device, which measured maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP), as indicators of inspiratory and expiratory muscle function, respectively. Cardiopulmonary fitness was determined using the Bruce Submaximal Treadmill Protocol, and the predicted VO2 peak was calculated as a measure of aerobic capacity.
The results demonstrated significant differences in body composition and respiratory muscle strength between the two groups. The average BMI and body fat percentage for the NF group were 21.06 ± 2.4 kg/m² and 32.25 ± 6.4%, respectively, while the HF group had significantly higher values of 30.90 ± 5.6 kg/m² and 44.30 ± 5.9%. Similarly, VO2 peak was lower in the HF group (33.20 ± 6.8 mL/kg/min) compared to the NF group (39.51 ± 6.1 mL/kg/min), with a statistically significant difference (p = 0.0003). Regarding respiratory muscle strength, the HF group exhibited lower MIP (52.25 ± 14.32 cmH2O) than the NF group (62.53 ± 13.0 cmH2O) (p 0.05). No significant differences were observed between the groups in terms of MEP. The linear regression analysis indicated that body fat percentage and MIP together accounted for 39% of the variance in VO2 peak (F(2, 61) = 19.62, p 0.001). This suggests that both body fat and respiratory muscle strength play significant roles in determining cardiorespiratory fitness levels in women.
This study highlights the detrimental effects of higher body fat percentage on both respiratory muscle strength and overall cardiorespiratory fitness in women. Individuals with higher body fat percentages not only had lower VO2 peak values, indicating poorer aerobic capacity, but also demonstrated reduced inspiratory muscle strength, which could further impair physical performance.
Importantly, the findings underscore that interventions aimed at improving fitness should not solely focus on weight loss but should also target strengthening respiratory muscles, particularly in women with higher fat percentages. Given the significant impact of both body fat percentage and MIP on cardiopulmonary fitness, healthcare professionals should consider incorporating respiratory muscle training as part of obesity management and fitness enhancement strategies.
Fitness
Respiratory Muscle Strength
