Physically fit adults are less likely to develop lung and bowel cancer - and more likely to survive them if they do, according to a new study.

Researchers found those with higher fitness levels before diagnosis were less likely to die compared to unfit adults.

There is limited data on the relationship between cardiorespiratory fitness and lung and bowel cancer risk and mortality.

But new research from Johns Hopkins School of Medicine in the US contributed the largest study to date.

Dr Catherine Handy Marshall and her colleagues studied 49,143 adults who underwent exercise stress testing from 1991-2009.

The participants were followed for an average of 7.7 years.

Those in the highest fitness category had a 77 per cent decreased risk of developing lung cancer and a 61 per cent decreased chance of developing colorectal cancer.

Among those who developed lung cancer, those with the highest fitness had a 44 per cent decreased risk of dying during follow-up.

Researchers found that among adults who developed colorectal cancer, those with the highest fitness had an 89 per cent decreased risk.

Dr Marshall said: "Our findings are one of the first, largest, and most diverse cohorts to look at the impact of fitness on cancer outcomes.

"Fitness testing is commonly done today for many people in conjunction with their doctors.

"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."

The team concluded that additional studies were needed to determine if improving fitness influences risk and mortality rates of all cancer.

The findings were published in the journal Cancer.