Association between skeletal muscle mass and cardiorespiratory fitness in community-dwelling elderly men

Background: Sarcopenia reduces physical ability and cardiorespiratory fitness (CRF), leading to poor quality of life. Aim: The aim of this study was to investigate the relationship between skeletal muscle mass and CRF in elderly men. Methods: We assessed 102 community-dwelling men over 60 years old. Appendicular skeletal muscle mass (ASM) was determined using bioelectrical impedance analysis, and the skeletal muscle mass index (SMI) was calculated as ASM divided by the square of height. Subjects with an SMI less than 7.0 kg/m were included in the sarcopenic group, as recommended by the Asian Working Group for Sarcopenia. To investigate CRF parameters, a cardiopulmonary exercise test was performed using the Bruce protocol. CRF parameters were subdivided into aerobic capacity, cardiovascular response, and ventilatory response. Results: Of the 102 subjects, 15 (14.7%) were included in the sarcopenic group. There were significant correlations between SMI and peak oxygen consumption (VO ) (r = 0.597, p < 0.001), and between SMI and VO /weight (r = 0.268, p = 0.024). Moreover, there were positive correlations between SMI and first ventilatory threshold (VT1) (r = 0.352, p = 0.008) and between SMI and VT1/weight (r = 0.189, p = 0.039). Additionally, peak oxygen pulse (O pulse ) was significantly correlated with SMI (r = 0.558, p < 0.001). VO , VO /weight and O pulse showed significant differences between the sarcopenic and non-sarcopenic groups (p < 0.05, all). In multiple linear regression analyses, the factor related to VO was SMI (β = 0.473, p < 0.001) and that related to O pulse was also SMI (β = 0.442, p < 0.001). Discussion and conclusions: This study demonstrated that skeletal muscle mass might be closely associated with CRF. Therefore, sarcopenia should be appropriately managed to improve an individual’s CRF.