Exercise may protect against cancer, study says

Physical fitness may protect against both lung and bowel cancers.

Researchers from Johns Hopkins School of Medicine in Baltimore used data from nearly 50,000 health patients, who had undergone exercise stress tests between 1991 and 2009.

They found the fittest adults had the lowest risk of lung and colorectal cancer.

Researchers also linked higher fitness before diagnosis to better survival rates among those who developed either cancer.