Physical activity, cardiorespiratory fitness, and exercise training in primary and secondary coronary prevention
Abstract by Dr. Laurie Malone
As we know, physical inactivity or a sedentary lifestyle is associated with numerous health issues. Given this month’s focus on heart health, this article will provide an overview of the relationship between physical activity and cardiovascular disease (CVD). The main forms of CVD are coronary heart disease (CHD) and stroke. About half of all deaths from CVD are from CHD and about a quarter are from stroke. As noted by the American Heart Association (www.americanheart.org), physical inactivity is a major modifiable risk factor for CHD. A recent review by Swift et al. (2013) highlights the role of physical activity and exercise in protecting against heart disease.
Numerous epidemiological studies have shown an inverse relationship in both men and women between level of physical activity and cardiovascular risk factors such as type 2 diabetes mellitus, hypertension, metabolic syndrome, and obesity. As level of physical activity increases from moderate to high, corresponding reductions in risk of CHD are seen. In addition, a strong relationship between low levels of physical activity and CVD mortality has been established. The reduction in CVD mortality associated with greater levels of physical activity also applies to higher risk populations such as older adults and individuals with diabetes.
Beyond leisure-time physical activity, activity gained during work also plays a role in reducing CHD and CVD mortality risk. Significant reductions in risk have been found in both men and women with high levels of job-related physical activity independent of age, body mass index, systolic blood pressure and leisure-time physical activity.
In looking at the interaction between level of physical activity and obesity on risk of CVD/CHD, mortality studies have found that although higher levels of physical activity attenuate the risk associated with obesity, they do not completely eliminate it. Also important to consider is level of cardiorespiratory fitness. Similar to level of physical activity, fitness level is inversely related to CVD and CHD mortality, including in otherwise high-risk individuals (i.e., diabetes, metabolic syndrome). Especially important to note is the independent effect of fitness on obesity. Regardless of BMI or level of fat mass, CVD mortality risk is reduced with a high level of fitness. It is important to note that being lean but unfit still increases CVD mortality risk.
Given the benefits of physical activity and exercise on CVD risk factors, numerous health organizations such as the American Heart Association, American Diabetes Association, American College of Sports Medicine, and the National Institutes of Health have released position stands and recommendations on this topic. Swift et al. (2013) provide a nice outline of the recommendations in Table 2 of the article, which can be accessed by clicking the link at the bottom of the page.
The exercise recommendations are based on the necessary dosage to produce health benefits. The benefits of exercise on specific CVD risk factors and other components of health (physical and mental) are shown in the Table 1 in the article.
As we can see, being physically active and maintaining a high level of cardiovascular fitness are critical to maintaining the health of our hearts. Engaging in exercise may help us live longer by reducing many of the risk factors associated with CVD/CHD. Leading a sedentary lifestyle is a key modifiable risk factor that we can change. So, take charge, get moving, and keep your heart healthy.
The article, including the tables referenced in this abstract, can be viewed in its entirety by clicking here and then clicking "Full Text PDF [1291 k]."
Swift, D. L., Lavie, C. J., Johannsen, N. M., Arena, R., Earnest, C. P., O’Keefe, J. H., Milani, R. V., Blair, S. N., & Church, T. S. (2013). Physical activity, cardiorespiratory fitness, and exercise training in primary and secondary coronary prevention. Circulation Journal, 77, 281-292.