Weight training in coronary artery disease and hypertension

Abstract

0 VER THE PAST 10 to 15 years, physical exercise has played a role in the therapeutic management of coronary artery disease (CAD) and hypertension. Individuals who exercise regularly realize increased physical working capacity, improved cardiac risk factor profiles, and for CAD patients, better control of symptoms. The prevailing point of view has been to encourage as much physical activity as possible within the physiological and medical limitations of the patient, ie, angina, excessive blood pressure, ischemia, and left ventricuiar dysfunction. For CAD and coronary-prone patients, the major emphasis has been on developing cardiovascular fitness. Activities for cardiovascular fitness entail rhythmic movements of the larger muscle groups against relatively small resistance during efforts lasting minutes or longer, ie, walking, jogging, swimming, cycling, running, and rowing. These activities increase the demand for oxygen, which is the reason they are called “aerobic” exercise. As a result of aerobic training, there is better distribution of cardiac output, more oxygen extraction from a given blood flow by the muscles, and lower heart rate and blood pressure at rest and during submaximal work. Consequently, the patient can do more work with less cardiac effort. This is especially important to CAD patients who may have limited blood supply through the coronary arteries. Additional emphasis has been placed on cardiovascular fitness in high-risk individuals because this trait is linked to coronary disease risk factors such as hypertension, hyperlipidemia, diabetes, and obesity. Another approach to exercise training has been weight lifting using machines or free weights. Weight training is widely used to increase strength, power, and muscular endurance. Strength-trained individuals show a marked degree of muscle hypertrophy and lean body mass. Improvement in strength, especially upper body strength, is important for many high-risk patients (Table 1). In the past, patients have been restrained from weight lifting largely because of concern that increased exertional blood pressure can lead to a markedly elevated rate pressure product, myocardial ischemia, and ventricular arrhythmias. For many CAD patients with occupations requiring moderate weight lifting, return to work has often been delayed because of fear of complications, resulting in individual anxiety and economic hardship. However, increased strength should benefit CAD patients during activities requiring lifting, pushing, pulling, or carrying constant loads. Because the magnitude of the pressor response to static work is proportional to the percentage of maximal voluntary contraction,’ increased strength should lower the pressor response at a given work load because the load after training now represents a lower percentage of maximal. This article examines the benefits and risks of weight training for CAD and hypertensive patients, and provides specific recommendations for patient selection as well as guidelines for training and safety.