• Posted July 3, 2023

Staying Fit Lowers a Man's Cancer Risk, Study Confirms

A man's cardio fitness might influence whether he'll develop -- or survive -- three of the most common cancers in males, a new Swedish study reports.

Higher levels of cardio fitness are associated with a significantly lower risk of developing colon and lung cancers, researchers report.

Cardio fitness also plays a role in a man's likelihood of surviving prostate, colon and lung cancers, results show.

"Better cardiorespiratory fitness [CRF] is not only important for reducing cardiovascular disease risk, which is often communicated, but also for reducing cancer risk in men,"said lead researcher Elin Ekblom-Bak, a senior lecturer with the Swedish School of Sport and Health Sciences in Stockholm.

"Current cancer prevention guidelines focus on physical activity, but these findings show that CRF is also very important for both reducing cancer risk and risk of death from common cancers in men,"Ekblom-Bak said.

For this study, Ekblom-Bak and her colleagues analyzed data on nearly 178,000 Swedish men, all of whom completed an occupational health assessment between October 1982 and December 2019.

As part of this assessment, the men tested their cardio health on an exercise bike, with doctors registering their blood oxygen levels as they pedaled.

Researchers then tracked the men's health using Swedish health registries, to see which men wound up developing cancer.

They specifically found a strong dose-response association between cardio fitness and lower risk either developing or dying from certain cancers, Ekblom-Bak noted.

In other words, the better a man's fitness, the lower their cancer risk.

For example, moderate and high levels of cardio fitness were associated with a 28% and 37% lower risk of developing colon cancer, compared to very low fitness.

Men with moderate and high levels of cardio fitness were also 43% and 71% less likely to die from prostate cancer than men with very low fitness, results show.

The risk of death from lung cancer was 59% lower in men with high cardio fitness, after adjusting for smoking, researchers found.

The findings were published June 29 in the journal JAMA Network Open.

The study is unique in that so many men received a "gold-standard test"of their cardio fitness, as well as doctor-measured reports of their height and weight, said Dr. Jennifer Ligibel, director of the Leonard P. Zakim Center for Integrative Therapies and Healthy Living at the Dana-Farber Cancer Institute in Boston.

"This was a very large study with great follow-up and gold-standard measurements for these patients,"Ligibel said.

Previous research has shown that better fitness can improve the cancer risk of both men and women, she said.

"There's a lot of physiologic things that can happen when somebody exercises and becomes more cardiovascularly fit that we know can be linked to the risk of developing cancer or the risk of dying from cancer,"Ligibel said.

For instance, people tend to have less inflammation and better blood sugar levels if their cardio fitness is better, said Dr. Nicholas Rohs, a thoracic oncologist at Mount Sinai Tisch Cancer Center. They also are leaner and can have lower cholesterol levels.

"These things place stress on our cellular systems, and the more stress we have on our body, the more likely that cancer is to occur,"Rohs said.

Given these results, men should be aware that the health benefits of exercise are many and varied, Ekblom-Bak said.

"The physical activity guidelines from the World Health Organization promotes the message 'Every move counts,' meaning any amount of physical activity is better than none, and more is better,"Ekblom-Bak said.

"To increase or maintain your fitness, the intensity has to be at least moderate, which often is described as the feeling of somewhat hard, with your breathing quickening,"Ekblom-Bak said. "However, the increase in fitness is both related to the intensity and the amount of physical activity performed, but also to individual genetic factors."

Rohs agreed.

"For an everyday person trying to act on this, higher cardiovascular intensity exercise like brisk walking, biking, jogging, swimming are ways to really get our heart rates up, get better cardiovascular output,"Rohs said.

"That's how we really train our heart and lungs to be healthier,"Rohs continued. "Anything that gets your heart going at a faster rate, your breathing increased, you're sweating -- these are all signs that your body's working extra hard. Pushing yourself to that level where you're feeling that kind of stress means that you're trying to push your body further and get stronger."

And it's very likely that these benefits would hold for women as well, Ligibel said.

"We know that women who exercise are at lower risk of cancer, too,"Ligibel said. "That's been shown for breast cancer, for colon cancer, for some of the gynecologic malignancies, so you would expect for this to be seen in women as well."

More information

The U.S. Centers for Disease Control and Prevention has more about measuring physical activity intensity.

SOURCES: Elin Ekblom-Bak, PhD, senior lecturer, Swedish School of Sport and Health Sciences, Stockholm, Sweden; Jennifer Ligibel, MD, director, Leonard P. Zakim Center for Integrative Therapies and Healthy Living, Dana-Farber Cancer Institute, Boston; Nicholas Rohs, MD, thoracic oncologist, Mount Sinai Tisch Cancer Center; JAMA Network Open, June 29, 2023