Exercise is widely known to improve health, but a recent high-quality clinical trial shows it can also significantly reduce the risk of colon cancer returning—matching the effectiveness of some chemotherapy treatments. This new evidence brings hope to cancer survivors looking for ways to improve their long-term outcomes through lifestyle changes.

The Study: How Exercise Helped Colon Cancer Survivors

Led by Canadian researchers, this phase 3 randomized clinical trial involved nearly 900 colon cancer patients who had already undergone surgery and chemotherapy. After those treatments, participants were divided into two groups: one followed a structured, supervised exercise program for three years, while the other received only health education.

The results were striking. Over an eight-year follow-up, the exercise group experienced a 28% lower risk of cancer recurrence, new cancers, or death compared to the education group. In numbers, 80.3% of the exercisers remained cancer-free after five years, compared with 73.9% in the education group.

Survival Benefits Visible Within a Year

Researchers found the benefits started showing after just one year and increased over time. The overall survival rate (whether cancer returned or not) was 90.3% in the exercise group versus 83.2% in the education group, a difference of 7.1 percentage points. The risk of death was reduced by 37%—41 deaths in the exercise group compared to 66 in the control group.

According to the study published in the New England Journal of Medicine, the positive impact of exercise was comparable to many standard drug therapies currently used in cancer treatment.

What Kind of Exercise Made a Difference?

Interestingly, the exercise regimen wasn’t extreme. Participants were encouraged to do any recreational aerobic activity they enjoyed, such as brisk walking or jogging. Typical recommendations were 45 to 60 minutes of brisk walking three to four times a week or jogging 25 to 30 minutes for the same frequency.

The goal was to achieve 20 MET hours per week. MET, or Metabolic Equivalent of Task, measures the energy burned compared to resting. Brisk walking counts as about 4 METs, and jogging about 10 METs. So five hours of walking or two hours of jogging weekly could meet the target.

Exercise Group Showed Better Fitness and Function

During the study, the exercise group received coaching and supervision for six months, which helped them reach over 20 MET hours weekly by the end. In comparison, the education group averaged about 15 MET hours.

The exercisers also showed improved cardiorespiratory fitness and physical functioning. The control group, despite only receiving health education, still increased their exercise from about 10 MET hours per week, suggesting the real effect might be even greater if compared to completely inactive individuals.

Why Does Exercise Help Fight Cancer?

The exact biological reasons exercise reduces cancer risk are still being studied. Theories include enhanced immune surveillance, reduced inflammation, better insulin sensitivity, and changes to the environment where cancer might spread.

The study found exercise lowered the chance of both local and distant colon cancer recurrence and helped prevent new cancers like breast and prostate cancer.

Experts Praise the Findings

Experts outside the study were impressed. Marco Gerlinger, a gastrointestinal cancer expert, called the results "quite impressive," noting that oncologists can now confidently recommend exercise as a way to reduce cancer recurrence.

David Sebag-Montefiore, a clinical oncologist, highlighted the appeal of exercise as a treatment without the side effects of chemotherapy. He called it a breakthrough for improving cure rates with moderate, structured exercise.

This study strengthens the case for regular physical activity as a powerful, accessible way to improve survival and quality of life for colon cancer survivors.