Hazard ratios of metabolic syndrome by meeting the 2008 US Physical Activity Guidelines for resistance (≥2 days/week) and aerobic activities (≥500 MET-minutes/week) at baseline. The bars present hazard ratios (95% confidence intervals). The model was adjusted for age (years), gender, examination year (year), body mass index (kg/m2), current smoking (yes/no), heavy alcohol drinking (yes/no), abnormal electrocardiography (yes/no), and parental history of cardiovascular disease, hypertension and diabetes (yes/no for each).