Two animal studies published in the journal Carcinogenesis show that exercise can offer protection against cancer. One study found that physically active mice that had a round the clock access to wheels took longer to develop skin tumors, while the other study found that exercise and a restricted diet had a healthy effect on mice by decreasing pre-cancerous bowel growths in the animals.
The first study exposed mice to ultraviolet B rays of the sun that is harmful to the skin. The study was led by Professor Allan Conney of Rutgers University, New Jersey, USA. He felt that exercise probably hastened the physiological cell death, "Preliminary indications from follow-up work in the laboratory suggest that voluntary exercise enhances UVB-induced apoptosis in the skin, and that it also enhances apoptosis in UVB-induced tumors," said Prof Conney. "So, although UVB is triggering the development of tumors, exercise is counteracting the effect by stimulating the death of the developing cancer cells."
The second study led by Dr Lisa Colbert, from the University of Wisconsin-Madison, USA, increasing the energy output, while at the same time decreasing calorific intake played a big role in inhibiting polyps, which are implicated in the formation of bower cancer.
Previous population studies have already found a positive relation between exercise and cancer reduction. "On average there were 16 polyps per mouse in the exercising mice compared to 22 polyps in the control mice, a decrease of 25%," said Dr Colbert.