In brief:There is little evidence that isometric exercise benefits the cardiovascular system, and many physicians believe that it imposes undue demands on the myocardium, so they prohibit such exercises for middle-aged or coronary disease patients. This review article examines the validity of this conclusion by summarizing the effects of isometric exercise on heart rate, blood pressure, myocardial demand, cardiac output, peripheral blood flow, and left ventricular function. Dr. Fardy concludes that isometric exercise is less hazardous than has been presumed and says guidelines should be established according to each patient's history.