Amount and intensity of physical activity in relation to cardiorespiratory fitness in japanese middle-aged and elderly men

PURPOSE: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 (V̇O₂max/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.