• A new study found a link between higher fitness levels and lower risk of cancer of the lungs, liver, esophagus, stomach, kidney, head and neck, bowel, pancreas, and rectal cancer.
• While the research was done on men, other studies point to cancer-prevention benefits of exercise for women, too.

Can adopting an active lifestyle early help manage your risk of cancer? Although it’s never too late to improve your cardiorespiratory fitness, a recent study in the British Journal of Sports Medicine highlights how building your endurance when you’re younger can pay off in major ways decades later—particularly when it comes to cancer prevention.

Researchers drew on Swedish registry data of more than 1 million military conscripts who began their service between 1968 and 2005. This provided initial info on cardiorespiratory fitness, as measured by VO2 max and maximum wattage, through the use of a cycling test.

Looking at how many participants developed cancer by 2019, researchers found those with higher cardiorespiratory fitness levels when younger had significantly lower incidence of cancer over time. This included lower risk for cancers of the lungs, liver, esophagus, stomach, kidney, head and neck, bowel, pancreas, and rectal cancer.

Because this is an observational study, we can’t draw conclusions about cause and effect, particularly because there was no data on other risk factors like diet, alcohol intake, and smoking, as well as genetic factors. However, the results were strong enough that researchers recommended public health policymaking that centres around boosting cardiorespiratory fitness for younger people.

The best ways to increase cardiorespiratory fitness include doing aerobic activities like cycling, even at lower intensities. But HIIT workouts, tempo rides, and hill repeats, can also help to increase VO2 max and your overall fitness levels.

Another note: Although the recent study focused on reduced cancer risk in men, previous studies have shown similar results for women as well.

For example, in a meta-analysis of 33 studies, highly physically active women had a lower risk of endometrial cancer than women with lower exercise levels. Another meta-analysis that included 38 cohort studies showed a reduced risk for breast cancer, and the National Cancer Institute (NCI) noted that women who increase their physical activity after menopause may have lower risk of breast cancer than those who are more sedentary.

In terms of why this connection exists, the NCI reported that exercise has numerous biological effects on the body that can affect cancer growth. For example, physical activity reduces inflammation, improves immune system function, helps regulate hormone function, and prevents high blood levels of insulin, and all of those have significant effects when it comes to cancer prevention.

“Prevention strategies are obviously crucial when it comes to cancer risk, especially since we don’t have regular screenings for the majority of cancers,” said Elena Pereira, M.D., an ob-gyn.  She told Bicycling that routine screening is not done for endometrial cancer, for example, which is why knowing the signs of that cancer (like bleeding or discharge) is important, but lifestyle habits that reduce risk are also key.

Even for those who’ve already had cancer, exercise can be a boon, research suggests. In a review of observational studies, breast cancer survivors who were the most physically active had better longevity compared to survivors who were least active. The same has been shown for other types of cancer too, including colorectal cancer and prostate cancer.

A report from an American College of Sports Medicine roundtable on cancer prevention noted there’s strong evidence that moderate-intensity aerobic training or resistance exercise during and after cancer treatment can reduce anxiety, depressive symptoms, and fatigue, while improving physical function.

The takeaway from all this research? You might not be thinking about cancer prevention or treatment when you grab your bike and head out on a ride, but it’s very likely you’ll be affecting your cancer risk levels when you do, so keep going the distance.