Physical activity and structured exercise for patients with stable ischemic heart disease.

EXERCISE WAS RECENTLY DESCRIBED AS “A MIRACLE drug” that can benefit every part of the body and substantially extend lifespan. ” The authors suggested that the cardioprotective and systemic health benefits of regular exercise are underestimated by many clinicians, who often fail to emphasize the importance of regular physical activity, as well as the harms of physical inactivity, even though they routinely counsel patients about other modifiable cardiovascular risk factors, such as cigarette smoking, elevated cholesterol levels, and hypertension. If exercise is a central and indispensible component of a comprehensive strategy for the primary prevention of coronary artery disease, the mantra “exercise is medicine” may be even more valid and is too often undervalued as a critical element in secondary prevention. However, many patients with heart disease who qualify for and require exercise training as an essential part of their recovery process are not receiving this therapy, often because of a lack of awareness by patients, health care professionals, and payers of the necessity, appropriateness, and effectiveness of this intervention. This gap between scientific evidence and clinical practice is the focus of this Viewpoint, which discusses the importance of structured exercise and increased physical activity for patients with stable ischemic heart disease and the need to highlight the poor prognosis associated with being in the least fit, least active cohort (bottom 20%) for the 12 to 13 million US residents who comprise this population. One of the most puzzling aspects of the medical community’s failure to recommend regular exercise for patients with stable ischemic heart disease may be the fundamental simplicity and affordability of this intervention, particularly compared with other widely accepted preventive measures. For instance, the Clinical Outcomes Utilizing Revascularization and Aggressive Drug Evaluation (COURAGE) trial showed no difference in clinical outcomes in patients with stable ischemic heart disease (eg, death, myocardial infarction, hospitalization for unstable angina) during a mean 55-month follow-up between those who underwent percutaneous coronary intervention (PCI) and optimal medical therapy (including both risk-reducing and symptom-reducing therapies) and those treated with optimal medical therapy and lifestyle modification. Anginal symptoms were reduced in both groups, and there was no significant difference in health status between the groups, demonstrating that optimal control of risk factors could favorably affect outcomes. Despite clinical guideline recommendations that, among patients with stable ischemic heart disease, revascularization may be deferred until the effects of optimal medical therapy and lifestyle modification have been assessed and validated, more than half of the 1.3 million annual PCI procedures in the United States are performed electively for patients with stable ischemic heart disease, and only about 45% of these patients receive optimal medical therapy prior to their procedure. Equally concerning is that many of these patients do not participate in medically supervised or home-based exercise training programs, even after revascularization. Increased exercise or physical activity and cardiorespiratory fitness appear to mitigate cardiovascular disease progression. Exercise has antiatherosclerotic, antithrombotic, anti-ischemic, antiarrhythmic, and positive psychological effects, and secondary prevention exercise training regimens in conjunction with optimal medical therapy have been shown to reduce total mortality by 20%, cardiac mortality by 26%, and nonfatal myocardial infarction by 21%. Cardiorespiratory fitness may be expressed as metabolic equivalents (METs), for which 1 MET isapproximately 3.5 mL of oxygen per kilogram of body weight per minute (mL/kg/ min), which is equivalent to the energy requirement for basal homeostasis. Multiples of this value are often used to quantify relative levels of energy expenditure. Each 1-MET increase in exercise capacity is associated with an 8% to 35% (median, 16%) reduction in mortality, which compares favorably with the survival benefit conferred by low-dose aspirin, statins, -blockers, and angiotensin-converting enzyme inhibitors after acute myocardial infarction. Current guidelines recommend 30to 60 minutes of moderate-intensity aerobic activity at least 5 days a week for patients with stable ischemic heart disease to augment peak oxygen uptake and modify cardiovascular risk factors, as well as complementary resistance training at least 2 days a week to increase weight-carrying tolerance and skeletal muscle strength. Resistance training also attenuates the rate-