In vivo assessment of muscle mitochondrial function in healthy, young males in relation to parameters of aerobic fitness

摘要

PurposeThe recovery of muscle oxygen consumption (mVO(2)) after exercise provides a measure of skeletal muscle mitochondrial capacity, as more and better-functioning mitochondria will be able to restore mVO(2) faster to the pre-exercise state. The aim was to measure muscle mitochondrial capacity using near-infrared spectroscopy (NIRS) within a healthy, normally active population and relate this to parameters of aerobic fitness, investigating the applicability and relevance of using NIRS to assess muscle mitochondrial capacity non-invasively.MethodsMitochondrial capacity was analysed in the gastrocnemius and flexor digitorum superficialis (FDS) muscles of eight relatively high-aerobic fitness (VO(2)peak >= 57mL/kg/min) and eight relatively low-aerobic fitness male subjects (VO(2)peak <= 47mL/kg/min). Recovery of whole bodyO(2), i.e. excess post-exercise oxygen consumption (EPOC) was analysed after a cycling protocol.ResultsMitochondrial capacity, as analysed using NIRS, was significantly higher in high-fitness individuals compared to low-fitness individuals in the gastrocnemius, but not in the FDS (p=0.0036 and p=0.20, respectively). Mitochondrial capacity in the gastrocnemius was significantly correlated with VO(2)peak (R-2=0.57, p=0.0019). Whole body VO2 recovery was significantly faster in the high-fitness individuals (p=0.0048), and correlated significantly with mitochondrial capacity in the gastrocnemius (R-2=0.34, p=0.028).ConclusionNIRS measurements can be used to assess differences in mitochondrial muscle oxygen consumption within a relatively normal, healthy population. Furthermore, mitochondrial capacity correlated with parameters of aerobic fitness (VO(2)peak and EPOC), emphasising the physiological relevance of the NIRS measurements.