I. Perspective
The death of exercise enthusiast James Fixx is a good example of nonprotection by exercise. In his early 30s he recognized that he was at high risk because his family history was strong for heart attacks before age 50. A daily run of 5–10 miles for more than 15 years did not protect him from the silent killer. Note that during jogging and running the systolic blood pressure may be slightly or moderately increased. The combined increase in blood pressure and high-velocity blood flow may, over a period of years, increase atherosclerosis.
Strenuous exercise can precipitate death in individuals who have a very rare heart muscle problem called obstruc¬tive cardiomyopathy. The division (septum) between the right and left ventricle becomes extremely thick for reasons unknown and obstructs the blood flow from the left ventricle into the aorta. This condition explains the rare sudden death that occurs in some athletes under the age of 30. This obstructive heart muscle problem is fortunately very rare and is easy to exclude. This is done by a doctor listening with a stethoscope and with added tests such as an ECG and an echocardiogram. (See chapter entitled Cardiomyopathy.)
All patients with known heart disease or with symptoms that suggest heart disease — pain or discomfort in the chest, throat, jaw, or arms during activity; shortness of breath; palpitations (fast, pounding heartbeats or skipped heartbeats) — should have an assessment by a doctor and a stress test before engaging in moderate or vigorous exercise. Patients with previous heart failure or marked heart enlargement should engage only in moderate exercise such as walking or its equivalent. Exercise is well known to precipitate heart failure in such individuals; therefore, further advice from your doctor is necessary if you want to do exercise other than the equivalent of walking one mile daily.

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