Background. The prevalence of metabolic syndrome (MetS) has been increasing, and its risk is positively correlated with age. Due to ageing society in Taiwan, how to treat metabolic syndrome and decrease the complications is an important health issue. Relatively few studies have been focusing on the effects of exercise training in patients with MetS with long-term follow-up. Recently, high-intensity interval training or aerobic interval training (AIT) consisting of high intensity separated by active recovery has been proposed to be more effective than isocaloric continuous moderate-intensity exercise (CME) in raising exercise capacity (VO2max) in some specific patient population.