Colon or colorectal cancer begins in the colon (large intestine) or in the rectum. It is one of the leading causes of cancer among U. S. Citizens according to the American Cancer Society. Over the years, research has shown that a nutritious diet may help reduce risks for colon cancer, and now it appears that walking and other forms of exercise may also help lower these risks.

Results from a large study conducted at the Washington University School of Medicine in St. Louis found that women who walked an hour per week appeared to lower risks for colon cancer, and more activity brought even better outcomes. Researchers followed 79,295 female participants of the Nurse's Health Study who ranged from 40 to 65 years of age. Over the course of 16 years, 547 of the subjects developed colon cancer.

It was concluded that women who walked from 1 to 1.9 hours per week reduced their chances for developing colon cancer by 31 percent. Further, women who participated in moderate to intense physical exercise for more than 4 hours per week reduced chances for colon cancer by 44 percent, as compared to women who exercised less than one hour per week.

The researchers concluded, "Leisure-time physical activity should be encouraged for all adults for health benefits, including colon cancer prevention."

A recent review of 52 studies over the last 25 years also concluded that walking and other forms of exercise may reduce the chances for developing colon cancer. In fact, it was determined that regular physical exercise can lower risks by up to 25 percent.

The study - published in the British Journal of Cancer looked at research involving many forms of physical activity including walking, jogging, gym workouts and manual labor. Out of thousands of subjects, those who were the most active were the least likely to develop colon cancer, with the benefits equal for both men and women. Remarkably, the protective effects persisted even when other risk factors like poor diet and smoking were present.

It has been suggested that exercise helps to lower chances for colon cancer by helping the individual maintain a healthy weight and boosting the speed at which toxic substances pass through the large intestine and out of the body. Exercise has also been shown to help reduce inflammation in the bowels and lower levels of certain hormones linked to tumor growth.

While a sedentary lifestyle and obesity have been linked to an increased risk for colon cancer, here are a few other factors that may also increase risks:

Family history of colon cancer
A history of ovarian, uterine or breast cancer in women
A poor diet high intake of red meats and processed foods and low intake of whole grains, fruits and vegetables
Cigarette smoking especially in those who have smoked long term