Heart Diseases

Physician William Osler observed in 1910 that certain types of people were most likely to develop coronary artery disease, particularly individuals who were "keen and ambitious." Contemporary efforts to prevent heart disease focus on identifying types of behavior and activity that increase the risk of heart disease and on encouraging individuals to adopt healthier lifestyles.

The massive body of evidence linking various types of risk factors to heart disease derives from a series of ambitious twentieth-century studies of heart disease in large groups of people over a long period of time. One of the best known of these efforts is the Framingham study, which has traced thousands of residents since 1949. This and other studies have led to findings that individuals are at a greater risk of heart disease if they have high levels of certain types of cholesterol in the blood, if they smoke cigarettes, if they are obese, if they have high blood pressure, and if they are male. Blood cholesterol, a fat-like substance found in all human and animal tissue, is a primary focus of efforts to prevent heart disease. High cholesterol levels are shaped, in part, by diet and can be lowered. Experts suggest limiting consumption of foods high in saturated fats, such as cream, meat, and cheese. Such a diet reduces the risk of high levels of low-density lipoprotein, or LDL, the type of cholesterol which increases the risk of heart disease.

Exercise has also been promoted as a protection against heart disease. Numerous studies have shown that individuals who do not exercise are more likely to develop coronary heart disease. Exercise reduces blood pressure and eases blood flow through the heart. In addition, people who exercise are less likely to be overweight.

Individuals who burn more calories are also more likely to have higher levels of what has been called the "good" cholesterol—high-density lipoprotein, or HDL. This type of cholesterol is believed to reduce the risk of heart disease. Other activities that boost the level of HDL include maintaining average weight and not smoking cigarettes.