Physical activity to prevent cardiovascular disease. How much is enough?

OBJECTIVE To review the role of physical activity in primary prevention of cardiovascular (CV) diseases with particular attention to the intensity and amount of physical activity needed to benefit health.

QUALITY OF EVIDENCE MEDLINE was searched for articles published in the indexed English literature from January 1991 to December 2000 using key words related to physical activity (e.g., exercise, physical fitness), CV and coronary artery disease (CAD) risk factors (e.g., diabetes, hypertension, hyperlipidemia, obesity). Findings were supplemented by consensus documents and other published literature. Most articles described prospective observational studies.

MAIN MESSAGE Clear evidence indicates an inverse linear dose response between amount of physical activity and all-cause mortality, total CV disease, and CAD incidence and mortality. The minimal effective dose is unclear, but physical activity that results in energy expenditure of approximately 4200 kJ.week-1 appears to be associated with substantial benefits. Physical activity need not be vigorous to benefit health.

CONCLUSION Moderate activity, such as brisk walking for 30 to 60 minutes a day most days of the week, is associated with significant reductions in the incidence and mortality of CV disease.