Background and Aims : Peripheral artery disease (PAD) is more unrecognized compared to other cardiovascular diseases, and yet is the most common cause of tissue loss, infection and major amputation. It is reported that more than 200 million people have PAD worldwide. More than half of the patients diagnosed with PAD are asymptomatic. Despite the advanced nature of medical systems in many countries, the health hazard and economic burden of PAD remain high due to the requirement for frequent intervention.Thus, determining the aetiology of PAD and taking effective measures are very important to reduce the burden of this condition. Ankle brachial index (ABI) is the ratio of ankle to arm systolic pressure and a valid non-invasive measure that predicts for PAD as well as other cardiovascular events. Though there is good evidence for higher physical activity (PA) levels reducing risk of cardiovascular disease and exercise therapy is recommended for patients with intermittent claudication in latest European Society of Cardiology guideline for PAD, little is known about the association between the quantity, intensity of PA and the incidence of PAD. Besides, most of the studies included in the guideline are based on patients with intermittent claudication. The situation for general population is not clear and the dose-response relationship between PA and the incidence of PAD has not been reported before. This study aimed to determine whether there is a dose-response relationship between PA and the incidence of PAD in American adults by analyzing the data from National Health and Nutrition Examination Survey (NHANES) from 1999-2004.