12 In this study, the age-related decrease in peak oxygen uptake was also noted as per previous studies in Japanese subjects not taking any medications. The mean values obtained from this study also promise to be quite useful in reference databases for evaluating aerobic exercise levels defined by peak oxygen

uptake in Japanese subjects. In some literature, a relationship between aerobic exercise level and body composition has been reported. Watanabe et al.19 reported that maximal oxygen uptake was significantly and negatively correlated with body fat percentage in a small sample of 21 boys and 16 girls. Sanada et al.20 showed that the VT was significantly correlated with thigh skeletal muscle mass (men: r = 0.58, women: r = 0.47) in 1463 Japanese men and women. Yu et al. 21 also measured symptom-limited maximal oxygen uptake, and body composition using an impedance technique, click here and reported

that physical Trichostatin A molecular weight activity was an important determinant of the age-related decline in maximal oxygen uptake in Hong Kong Chinese. In patients with chronic heart failure, skeletal muscle mass was strongly predictive of maximal oxygen uptake at baseline and after exercise training. 22 In this study, peak oxygen uptake was significantly and negatively correlated with total body fat percentage using DEXA in apparently healthy Japanese men and women. In addition, peak oxygen uptake was weakly correlated with metabolic risk parameters. We have previously proved the link between the VT and leg strength per body weight in Japanese women in a cross-sectional study.23 In a longitudinal study, an increase in leg strength per body weight was associated whatever with improving metabolic syndrome and abdominal circumference in Japanese men.24 It was speculated to be difficult for subjects with

a smaller leg lean body mass to support the entire their body weight, and also difficult for those subjects with less leg lean body mass to carry out aerobic exercise, i.e., walking and jogging. In addition, peak oxygen uptake was also linked to total body fat percentage. It is well-known that fat is stored for energy, whereas muscle are the main engines that use energy. However, when aerobic exercise reached certain level, it starts to burn fat. Taken together, although aerobic exercise has been advocated as the most suitable activity for reducing body fat percentage and increasing aerobic exercise levels, such as peak oxygen uptake, it is important for subjects with smaller leg lean body mass to maintain or maximize the lean body mass of their lower limbs, as well as to carry out aerobic exercise, to reduce fat mass and increase peak oxygen uptake, thus resulting in improved metabolic risk factors in Japanese subjects. Potential limitations still remain in this study. First, our study was a cross-sectional but not a longitudinal study.