Staying physically fit may help reduce the risk of developing lung and colorectal cancer, according to a study.

The researchers from Johns Hopkins School of Medicine in the US studied 49,143 adults who underwent exercise stress testing from 1991-2009 and were followed for about 7.7 years. The research, published in the journal Cancer, showed that adults who were the most fit had the lowest risk of developing lung and colorectal cancer.

Among those who developed lung or colorectal cancer, people who had high fitness levels before their cancer diagnosis were less likely to die compared with those who had low fitness levels. There is limited data on the relationship between cardiorespiratory fitness and lung and colorectal cancer risk and mortality.

The study represents the largest of its kind, as well as the first of its kind to involve women and a large percentage of non-white individuals. Participants in the highest fitness category had a 77 per cent decreased risk of developing lung cancer and a 61 per cent decreased risk of developing colorectal cancer.

Among individuals who developed lung cancer, those with the highest fitness had a 44 per cent decreased risk of dying during follow-up, and among adults who developed colorectal cancer, those with the highest fitness had an 89 per cent decreased risk.

“Our findings are one of the first, largest, and most diverse cohorts to look at the impact of fitness on cancer outcomes,” said Catherine Handy Marshall, from Johns Hopkins.

“Fitness testing is commonly done today for many people in conjunction with their doctors,” Handy Marshall said in a statement. “Many people might already have these results and can be informed about the association of fitness with cancer risk in addition to what fitness levels mean for other conditions, like heart disease,” she said.
Additional studies are needed to expand on these results and to determine if improving fitness can influence risk and mortality rates of cancer.