While physical activity has powerful disease prevention properties, it is no less of an ally when it comes to curing and managing diseases. The most striking example is perhaps its role in cardiac rehabilitation. That's only the tip of the iceberg however. Sandra O'Brien Cousins and her research team from the University of Alberta report that physical activity plays an important role in the following diseases as well:

Cancer — Sedentary people tend to have a higher risk of colon cancer and breast cancer than active people. Active living contributes multiple health benefits to cancer patients.

Diabetes — Physical inactivity and a sedentary lifestyle make diabetic symptoms and complications even worse. The type of diabetes that starts in adulthood can be controlled totally or in part with a regular exercise and nutrition program.

Mental disturbances — Physical activity can reduce the negative symptoms of dementia such as Alzheimer's disease. It can also temper other mental disturbances in older adults. Being active reduces anxiety, tension and depression, improves sleep quality, induces relaxation, reduces the need for psychotropic drugs, improves social interaction and reduces disruptive behaviour.

Arthritis — Physical activity can eliminate or reduce the need for pain medications in people with osteoarthritis. A lack of activity, on the other hand, increases the risk of osteoarthritic symptoms.

Osteoporosis — Present evidence suggests that exercise retards the rate of bone loss. Without exercise, bones tend to weaken with age and can reach a critical level in older adults, leaving individuals susceptible to fracture. As many as one in four women and one in eight men develop osteoporosis in their lifetime, which sometimes result in fatal fractures of the hip. Weight-bearing exercise, where people carry their weight on one leg at a time as in walking, and resistance training are needed to maintain and even strengthen bones.

Hormonal problems — There are growing indications that regular exercise helps to retard the loss of hormone function. Growth hormone, a builder of lean tissue, decreases with age but is released during exercise in young and old alike. Cortisol, a stress-fighting hormone, tends to stay too long in the blood in older people. Physical activity helps to keep it down. A similar balance is imposed on insulin, the sugar-controlling hormone. Norepinephrine — a waistline-destroying hormone — tends to be produced in abundance with age but can be kept in check by physical activity.

Lung disease — Exercise cannot restore damaged lung tissue but it can greatly improve lung endurance. People who experience progressive breathlessness due to chronic obstructive pulmonary disease (a disease strongly linked to smoking) sometimes find that trying to exercise leads to severe breathlessness and, understandably, a lack of enthusiasm for physical activity. For them, the optimum exercise program consists of walking for short periods with adequate rest intervals, resistance training to strengthen other weakened muscles and supervised breathing exercises.

If you or someone you know has any of the above conditions, physical activity may be the most positive step toward better health. Find an activity you really enjoy and seek out a friend to keep you company.