It is not as obvious as diet and exercise, so let me provide a little background. The classical stress reaction is designed to prepare the body for ''fight or flight'' action. Under stress, blood pressure begins to rise. Blood flow to the skin and the digestive system is reduced, and a greater supply is directed toward the large muscle groups. In preparation for any potential injury, platelets, the blood components that help stop bleeding, increase in number.
Danger exists for individuals under chronic stress who are at high risk for cardiovascular disease.
Blood clots are involved in heart attacks and strokes, so when you figure in the increased level of clot-producing platelets and the higher blood pressure, it's easy to see why stress is associated with a higher incidence of heart disease. The method one chooses for stress reduction is personality-dependent. General guidelines would include having outlets for stress, such as your exercise program and other recreational activities. It also helps to have friends with whom you can share both the good times and the bad. And finally, some find relief in relaxation techniques such as meditation and yoga.