There are many types of cancer, but they can all be characterized by uncontrolled growth and spread of abnormal cells. If the spread is not controlled, it can result in death as vital passage ways are blocked and the body’s oxygen and nutrient supply is diverted to support the rapidly growing cancer. The term cancer is used to indicate any of the more that one hundred types of malignant tumors or neoplasm’s. The leading cancer killer for both men and women is lung cancer, followed by prostate or breast cancer, and colorectal cancer. Dietary factors and cigarette smoking account for nearly two-thirds of all cancers. Other important risk factors include reproductive factors (especially for breast cancer), environmental factors (especially radiation and radon exposure, and air pollution), family history, and physical inactivity and obesity.

The American Cancer Society has urged that to reduce cancer risk, people should avoid all tobacco use, consume low fat, high fiber diets containing plenty of whole grains, fruits and vegetables, be physically active and maintain a healthy weight, limit consumption of alcoholic beverages, and limit exposure to ultraviolet radiation.

Evidence is mounting in human and animal studies that regular physical activity does contribute to the prevention of cancer. Exercise appears to enhance the activity of certain cells in the immune system, especially natural killer cells, cytotoxic T cells and macrophages, which improves cancer fighting proficiency. Large groups of people have been followed for extended periods to see if those who exercise regularly have less incidence of cancer than those who lead an inactive lifestyle. The most impressive results have shown a protective effect of exercise against three common cancer killers; colon, breast and prostate cancer. An International panel of cancer experts concluded that as many as 30-40% of all cancer cases worldwide could be avoided if people ate a healthy diet, avoided obesity and participated in an adequate amount of exercise.

The exercise benefits for a cancer patient undergoing treatment can help counter feelings of fatigue and anxiety, and loss of muscular and cardiorespiratory fitness. For cancer survivors, a fitness program can help them regain their formal state of health and function (and more, depending on their initial status).