Physical Activity and Cardiovascular Disease: Directions for Future Research

Abstract

Regular physical activity is widely accepted as playing a crucial role in cardiovascular disease (CVD) preven- tion. However, despite extensive research in this field there are crucial gaps in our knowledge. This paper discusses future research directions including population subgroup-specific exercise doses, research in under represented populations, the role of cardiorespiratory fitness in predicting CVD risk, and novel biological mechanisms that might mediate the inverse association between physical activity and CVD risk. Regular physical activity is widely accepted as playing a crucial role in cardiovascular disease (CVD) prevention (1- 6). Current physical activity recommendations for the gen- eral population advocate the accumulation of at least 30 minutes of moderate intensity physical activity on five or more days a week or vigorous activity at least three times per week (7). However, despite extensive research in this field there are crucial gaps in our knowledge. Several important areas have emerged that include examining population sub- group-specific exercise doses that are required for primary and secondary CVD prevention; the association between physical activity and CVD in under-represented populations such as women, children, ethnic minorities, and clinical pa- tient groups; the role of physical activity and cardiorespira- tory fitness (CRF) in predicting future risk for CVD, and novel biological and physiological mechanisms that might mediate the inverse association between physical activity and CVD risk. There is surprisingly little epidemiological evidence on the cardio-protective effects of physical activity in relation to current recommendations. In a large prospective study of over 200,000 participants, those meeting the physical activ- ity recommendations had the lowest risk of CVD, although those that met the recommendations through vigorous activ- ity benefited to a greater degree (32% risk reduction) than those meeting recommendations through moderate activity (27% risk reduction) (8). One of the key messages of these recommendations is that activities performed during daily living, (e.g. walking or cycling, stair-climbing, gardening, home improvement work, intense housework) may be suffi- cient for the prevention of CVD and premature death. Al- though the evidence on the health benefits of walking, cy- cling, or stair-climbing is compelling, the degree of protec- tion conferred from intense domestic physical activity is less clear and future research must address this issue. Several large scale prospective cohort studies in men suggest that vigorous activity is more beneficial for protection against CVD (3,4). For example, in the Health Professional's follow up study, men who ran for an hour or more per week had a