Researchers at the University of Bristol have announced findings from a number of studies that confirm physical activity could significantly reduce the risk of bowel (colorectal) cancer and may also help prevent breast, prostate, lung and endometrial cancer.
They also found data showing that exercise could help patients recover from cancer and are launching their own study into the benefits of exercise for people undergoing cancer treatment.
Researchers from the Department of Exercise and Health Sciences at the University of Bristol analyzed data from 15 studies on physical activity and cancer prevention and found that people taking part in occupational or leisure activity could substantially reduce their risk of dying from cancer.
Lead researcher, Professor Ken Fox from the Department of Exercise and Health Sciences at the University of Bristol, says: "Physical activity is a crucial component of a healthy lifestyle and we have found a growing body of evidence that indicates it's importance in keeping cancer at bay."
The researchers also reviewed data on specific cancer types and found that exercise could help prevent bowel, lung, breast, endometrial and prostate cancer.
They found compelling evidence from 37 of the 51 studies reviewed on bowel cancer that regular exercise could cut the risk of developing the disease by 40-50 percent. However, the protective effect appeared to be confined to cancer of the colon with no relationship demonstrated for rectal cancer.
Professor Fox says: "The evidence of the beneficial effects of exercise is the strongest for colon cancer. The data suggests that lack of physical activity alone could be a major risk factor for the disease."
From 37 of the 52 studies on exercise and breast cancer incidence, scientists found evidence that showed typically a 30 percent reduction in the risk of the disease in women who exercised on a regular basis. Generally, the benefits of exercise were stronger for post-menopausal women than pre-menopausal women. There was some evidence that physical activity in puberty could reduce the risk of developing the disease but women exercising throughout their lifetime had a greater reduced risk.
Six out of eleven studies on lung cancer and exercise indicated a protective effect. The most recent of the studies found moderate activity, after lifestyle factors were taken into account, could reduce the risk of developing lung cancer by as much as 40 percent.
The review also pointed to there being a small protective effect of activity on endometrial and prostate cancer.
Professor Fox says: "Looking at the evidence to date, to help reduce their risk of cancer, people should aim to engage in physical activity of at least moderate intensity, for approximately 30 minutes on three or more days a week throughout their lifetime."
Researchers also concluded from 36 studies that physical activity could enhance the quality of life for cancer patients and survivors across a range of cancers, including leukemia, breast, bowel and prostate cancer.
Study author Clare Stevinson, also from the University of Bristol, says: "Cancer treatments such as surgery, chemotherapy and radiotherapy have various negative side-effects such as loss of physical function, fatigue, nausea, depression and anxiety. Exercise has been shown to enhance aerobic fitness and muscular strength as well as body composition, self-perceptions and mood and so could help improve a patient's quality of life.
"Although rest is commonly recommended for patients experiencing fatigue, a number of patient trials suggest that moderate exercise during and following cancer treatment is associated with less fatigue and increased energy," she adds.
SOURCE:
Cancer Research UK (http://www.cancerresearchuk.org)
