In recent years, one of the most provocative questions in cancer research has been whether a regular exercise habit can prevent the onset of certain types of cancer.
The answer, as with any cancer-related question, is complicated. But a recent study published in The British Journal of Sports Medicine offered insight into how regular physical activity affects the risk of prostate cancer, the second most common and deadly cancer in the United States for men.
In one of the largest efforts of its kind to date, researchers collected data between 1982 and 2019 from 57,652 Swedish men who had participated in at least two physical fitness tests to see if those who were more active were less likely to develop cancer. . About 1% were subsequently diagnosed with prostate cancer. The team found that those who had improved their physical fitness over the years were 35% less likely to have been diagnosed with the disease.
The finding is in line with much of the latest research on the relationship between fitness and cancer diagnosis. According to a 2021 study, for example, if all adults in the United States met physical activity guidelines, cancer diagnoses could be reduced by 3%, or 46,000 cases, each year.
But while there has been extensive research on the relationship between exercise and conditions such as breast cancer, there has been less research specifically on prostate cancer. The likelihood of prostate cancer increases for all men after age 50; The risk appears to be hereditary. According to the American Cancer Society, approximately 1 in 8 men will be diagnosed with prostate cancer during their lifetime.
Some previous studies looking at the connection between physical activity and prostate cancer have been contradictory, according to Dr. Kate Bolam, co-author of the study. While some showed an increased risk of prostate cancer among those who were physically active, others found a lower risk.
But many of those studies had small samples or were biased toward healthier people, said Bolam, a researcher at the Swedish School of Sport and Health Sciences.
“Men who are generally more conscious about their health,” he said, “are also good at going to the doctor when they are called in for their prostate cancer screenings.”
More tests mean more diagnoses, even in men whose cancers will never progress. Sometimes cancer cells can exist in the prostate for a lifetime and not be dangerous, so many men who don’t get tested and don’t experience symptoms may never know they have prostate cancer.
The Swedish team was able to create a more nuanced picture using a national database with hundreds of thousands of lab results, including fitness tests that measure how well the heart and lungs supply oxygen to the muscles.
Unlike studies that rely on patients reporting their exercise habits, this provided experts with objective measurements. The results clearly showed a link between physical activity and a reduced risk of prostate cancer. It also showed that greater improvements in physical fitness were associated with greater risk reduction.
This adds to a growing understanding of the importance of exercise for cancer prevention in general. In 2019, a review by the American College of Sports Medicine found that regular physical activity significantly reduced the risk of bladder, breast, colon, endometrial, esophageal, kidney and stomach adenocarcinoma. The same analysis also found that having a regular exercise habit was linked to better treatment outcomes and extended the life expectancy of those already living with cancer.
While it’s unclear exactly how this happens, experts said one explanation may be that exercise helps fight cancer by improving the way the immune system attacks and eradicates cancer cells.
“We know that even a single session of exercise helps our body release immune cells into our circulation,” said Neil M. Iyengar, a medical oncologist and medical scientist at Memorial Sloan Kettering Cancer Center in New York City, who was not involved in the study. the study. “It also helps improve the population of immune cells in our tissues that fight cancer cells.”
He added: “In someone who exercises, you see more immune cells that are actually capable of killing cancer cells. Whereas for someone who is more sedentary, especially someone who is obese, you see the opposite.”
Researchers still don’t know exactly the right dosage and the type of exercise that might be most effective, but both the American Cancer Society and the American Society of Clinical Oncology recommend 150 minutes per week, or 20 minutes per day, of aerobic exercise. This could be light walking, jogging, or weight training.
Both Iyengar and Bolam recommended starting simple: find an activity that’s enjoyable and get moving. It could be playing with children or grandchildren, going for a walk, or joining a recreational sports league. They said consistency is key, so it’s important to find an activity that doesn’t feel like a chore.
“Everyone has the opportunity to do something that is really profitable here to decrease the risk of prostate cancer,” Bolam said. “And that’s something that’s totally within our control.”