Adults who are the most fit are at lower risk of developing lung and colorectal cancer, while those who do develop these cancers and have high fitness levels are more likely to survive, according to a new study published in the American Cancer Society’s journal Cancer, reports Wiley.

Researchers studied nearly 50,000 adults who received exercise stress testing from 1991 through 2009 and were tracked for almost eight years. The adults were between 40 and 70 years old and didn’t have cancer.

After adjusting for several factors, such as age, sex and body mass index, people who exercised the most had a 77% decreased risk of developing lung cancer and a 61% decreased risk of developing colorectal cancer.

Among those who were eventually diagnosed with these cancers, researchers found that people with the highest level of fitness saw a 44% decreased risk of death from lung cancer and an 89% reduced risk of death from colorectal cancer.

“Fitness testing is commonly done today for many people in conjunction with their doctors,” said Catherine Handy Marshall, MD, MPH, of Johns Hopkins School of Medicine in Baltimore. “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.”

Despite these findings, experts say more research must be done to conclude whether fitness improvements can influence cancer risk and death rates. But for people with cancer, evidence has shown that exercise can help reduce fatigue, anxiety and depression and lead to better physical function, improved quality of life and fewer and less severe side effects.

For related coverage, read ‘Exercise Tied to Lower Liver Cancer Risk” and “Quick Reminder: Exercise Could Reduce Your Risk for Cancer.”