Although survival rates in patients with heart disease are improving, coronary heart disease remains the leading cause of morbidity and mortality in adults over 65 years of age. More older adults are living longer with chronic heart disease. The prevalence of heart disease increases with age and is one of the major causes of disability associated with aging. Heart disease also interacts with other diseases such as arthritis to synergistically increase the degree of disability. Shortness of breath is the most common symptom associated with decreased exercise tolerance. Fried and associates review the risk factors for cardiovascular disease in older adults and discuss prevention strategies.
Risk factors for myocardial infarction in older adults include elevated systolic blood pressure, cigarette smoking and elevated serum glucose levels. Subclinical cardiovascular disease is associated with a number of risk factors also associated with clinical disease. These include age, elevated systolic blood pressure, fasting glucose levels, high blood pressure and smoking in both men and women and, in addition, in women, diastolic blood pressure, low-density lipoprotein-cholesterol levels, high-density lipoprotein-cholesterol levels and leukocyte count. These data point to the importance of behavioral risk factors.
Cardiovascular changes that occur with aging include structural changes in the arterial vessel wall that lead to decreased vascular elasticity and result in an increase in systolic blood pressure and afterload. Resulting myocardial changes include left ventricular wall thickening and decreased left ventricular compliance. Diastolic abnormalities can be seen on echocardiography. Systolic function is less affected by the aging process. The resting ejection fraction does not appear to change with age. The resting heart rate and cardiac output remain relatively constant because of an increase in catecholamine levels offsetting decreased beta-adrenergic receptor activity. Overall, the resting heart adapts well to the structural and functional changes associated with aging.
Exercise emphasizes age-associated cardiovascular system changes. Notably, maximum oxygen consumption with exercise decreases substantially. Older adults increase their end-diastolic volume through the Frank-Starling mechanism to increase cardiac output during exercise. In the presence of stressors on the heart, such as exercise, the ability to increase heart rate and contractility is impaired in older adults, as is oxygen extraction by functioning myocardium. An exercise training program, defined as 30 minutes of strenuous exercise three to four times a week for several years, can attenuate some of the adverse age-related changes that occur in the cardiovascular system. Exercise training can also positively affect body fat, blood pressure, cholesterol level and muscle mass.
The authors conclude that modifying risk factors by stopping smoking, controlling blood pressure and managing glucose levels is the key to improved cardiac health. Exercise training appears to be clearly beneficial in augmenting primary and secondary prevention, including directly reducing the incidence of myocardial infarction and lessening the symptoms of angina.
editor's note: Primary and secondary prevention of cardiac disease in the older adult has well-documented beneficial effects, including a decrease in cardiovascular disease and disability rates. In addition, an increased sense of well-being and functional capacity have been documented. Family physicians can encourage patients to initiate regular exercise programs in a manner most applicable to the individual patient's interests and values. Some patients will do well with organized exercise groups while others will prefer more individualized programs. Exercise should be initiated slowly and steadily increased to the recommended 30 minutes of strenuous aerobic exercise at least three times per week. Patients who need motivation may do best under direct supervision, increasing their heart rates at maximal exercise to 60 to 80 percent of maximum for their age—r.s.