PORPOSE: This study aimed to compare the prevalence of metabolic syndrome (MS) risk factors and its components in different levels of aerobic fitness established by “Exercise and Physical Activity Reference for Health Promotion 2006 (EPAR2006)” in Japanese middle-aged and elderly people.METHOD: Men (n=102) and women (n=133), aged 30-69yrs, participated in this study. The prevalence of MS risk factors was evaluated as the number of MS risk factors, according to the diagnostic criterion for Japanese-specific MS. Aerobic fitness was quantified as maximal oxygen uptake (VO₂max). Subjects were classified into the three groups by aerobic fitness level based on “Reference values” and “Reference range” established in EPAR2006; 1) High fitness group (H); VO₂max (mL/kg/min) is higher than “Reference values”, 2) Medium fitness group (M); VO₂max is below “Reference values” but within “Reference range”, 3) Low fitness group (L); VO₂max is lower than “Reference range”.RESULTS: In men, M and L groups showed significantly higher frequency of risk factors for MS than H group (H: 1.09±0.98, M: 1.81±1.07, L: 2.27±0.70, P＜0.01). In women, L group showed significantly higher frequency of risk factors for MS than H and M groups (H: 0.57±0.80, M: 0.81±1.01, L: 1.53±1.07, P＜0.01).CONCLUSION: These results suggest that higher MS risk appears when the VO₂max is lower than “Reference values” in men, and below “Reference range” in women, and that particularly, men with low aerobic fitness have higher MS risk.

PORPOSE: This study aimed to investigate the relation between cardiorespiratory fitness(CRF) and physical activity, especially vigorous physical activity, in Japanese middle-aged and elderly men.METHODS: Eighty-five men aged 30-69 years participated in this study. CRF was assessed by measuring the maximal oxygen uptake based on weight (VO₂max/wt) in an incremental test on a bicycle ergometer. METs·h/week was measured as the parameter of physical activity by using accelerometers. We defined the amount of physical activity higher than 3 METs as “Physical activity ; PA”in this study. Then, PA was divided into “Moderate physical activity ; MPA”(higher than 3 METs and below 6 METs)and “Vigorous physical activity ; VPA”(higher than 6 METs).RESULTS : CRF was positively correlated with PA(r=0.318, P<0.01), MPA(r=0.230, P<0.05), and VPA(r=0.301, P<0.01) and negatively correlated with age(r=-0.607, P<0.001), BMI(r=-0.369, P<0.01), and waist circumference(WC)(r=-0.486, P<0.001). After adjusting for age and WC, the multiple regression analysis revealed that PA was positively correlated with CRF(P<0.01). VPA was positively correlated with CRF(P<0.05) after adjusting for age, WC, and MPA. MPA was not correlated with CRF in the case of adjusting for age and WC.CONCLUSION : This study suggested that physical activity higher than 3 METs was positively associated with cardiorespiratory fitness independently of age and waist circumference, and particularly vigorous physical activity may contribute to increased cardiorespiratory fitness in middle-aged and elderly men. Thus physically active life with maintenance of adequate waist circumference may help to prevent age-related decline in cardiorespiratory fitness.