Multiple studies have now shown that people who maintain appropriate body fitness, using judicious regimens of exercise and weight control, have the additional benefit of prolonged life. Especially between the ages of 50 and 70, studies have shown mortality to be three times less in the most fit people than in the least fit. But why does body fitness prolong life? The following are the two most evident reasons.

First, body fitness and weight control greatly reduce cardiovascular disease. This results from (1) maintenance of moderately lower blood pressure and (2) reduced blood cholesterol and low-density lipoprotein along with increased high-density lipoprotein. As pointed out earlier, these changes all work together to reduce the number of heart attacks and brain strokes. Second, and perhaps equally important, the athletically fit person has more bodily reserves to call on when he or she does become sick. For instance, an 80-year-old nonfit person may have a respiratory system that limits oxygen delivery to the tissues to no more than 1 L/min; this means a respiratory reserve of no more than threefold to fourfold.

However, an athletically fit old person may have twice as much reserve. This is especially important in preserving life when the older person develops conditions such as pneumonia that can rapidly require all available respiratory reserve. In addition, the ability to increase cardiac output in times of need (the “cardiac reserve”) is often 50 per cent greater in the athletically fit old person than in the nonfit person.

Buy the Book that holds this excerpt: Textbook of Medical Physiology: With STUDENT CONSULT Online Access

Related Articles