Chronic obstructive pulmonary disease (COPD) is one of the leading causes of morbidity and mortality and a major burden on healthcare systems worldwide, but the search for potential preventive strategies is ongoing. While smoking is the most significant risk factor for COPD, 1 only around 20% of smokers develop it. 2 Therefore, other environmental and lifestyle factors are likely to impact the development of this disease. Physical activity (PA) is beneficial for mental health and a proven protective factor for non-communicable diseases including but not limited to cardiovascular disease, type-2 diabetes, breast cancer, and colon cancer. Thus, the World Health Organization (WHO) has recommended at least 150 minutes of moderate-intensity or 75 minutes of vigorous PA per week for good health. 3,4 In addition, some previous research indicated that COPD patients who engaged in PA were less likely to experience severe forms of the disease or to be hospitalized with it. 5 However, little research has been done on the role of PA in the primary prevention of COPD. A case-control study from Japan showed that lifelong PA is associated with a nearly 40% reduction in COPD risk. 6 Another cohort study in the U.S. also suggested that PA is linked to a reduced risk of developing COPD. 7 Nevertheless, research on the temporal relationship between different levels of PA and the risk of developing COPD in a representative population has been limited. Hence, we conducted this population-based longitudinal follow-up study in Taiwan to investigate whether PA is associated with a lower risk of subsequently developing COPD.