Many people believe that stress is a leading cause of heart attacks. When your doctor evaluates your risk for a heart attack, he or she can measure your fitness and your nutritional status objectively, and can tell you about hundreds of studies on the effects of diet and exercise that are based on solid science. But stress is subjective, not clearly defined or measurable. What one person considers stressful may be a motivating source of success to another. A situation that causes you great distress may be just a minor annoyance for someone else, and vice versa. We don