Exercise may be doing far more than keeping the heart healthy. New research from Newcastle University suggests that even 10 to 12 minutes of intense physical activity could help slow the growth of colorectal cancer cells by triggering faster DNA repair at a molecular level.

The study, published in the International Journal of Cancer, sheds new light on how physical activity may protect against cancer—not by treating it directly, but by altering biological pathways linked to tumour growth and genetic damage.

Looking beyond general benefits

Previous research has consistently shown that regular exercise reduces the risk of several cancers, including colorectal cancer. However, the precise biological mechanisms behind this protective effect have remained unclear. The Newcastle University researchers set out to explore how exercise influences cancer-related processes inside the body.

Their findings indicate that a single session of high-intensity exercise can lead to significant molecular changes that may make cancer cells less aggressive.

What the researchers did

The study involved 30 adults aged 50 to 78 who were overweight or living with obesity but otherwise healthy. Researchers selected this group because people with obesity and those with cancer often show similar acute molecular responses to exercise.

Participants completed a short, high-intensity exercise bike session, during which resistance was gradually increased until they reached maximum effort. The workout lasted just 10 to 12 minutes.

Blood samples were collected before and after the exercise session. Researchers then exposed colorectal cancer cells in the laboratory to serum derived from these blood samples.

Striking molecular changes

When cancer cells were treated with serum taken after exercise, researchers observed changes in the activity of more than 1,300 genes. Many of these genes were involved in DNA repair, tumour growth, and cell division.

One key finding was an increase in interleukin-6 (IL-6)—a protein known to play a role in DNA repair. At the same time, genes linked to rapid cell division were suppressed, suggesting a potential slowing of cancer cell growth.

Cancer cells exposed to post-exercise serum also showed faster DNA repair, even after being subjected to radiation in the lab—an important finding, as DNA damage is a hallmark of cancer progression.

Implications for colorectal cancer

Colorectal cancer—also known as bowel or colon cancer—is among the most commonly diagnosed cancers in the United States. According to the American Cancer Society, nearly 1.5 lakh people were expected to be diagnosed in 2025. Risk increases with age and is influenced by genetics and lifestyle factors, including diets high in red meat.

Treatment varies depending on the stage of diagnosis, ranging from surgery in early stages to chemotherapy and radiation in more advanced cases.

While the researchers caution that their findings do not mean exercise can treat cancer, they provide valuable insight into how physical activity may help reduce cancer risk or slow disease progression.

Not one-size-fits-all

The researchers also acknowledged that high-intensity exercise may not be feasible for all patients, particularly those undergoing cancer treatment. As a next step, the team plans to explore whether lower-intensity exercise could produce similar molecular benefits.

Still, the study highlights the remarkable biological impact of even a single short burst of intense exercise, reinforcing the growing view that physical activity plays a powerful role in cancer prevention and overall health.

As evidence continues to build, researchers say exercise should be seen not just as lifestyle advice, but as a key contributor to the body’s natural defence mechanisms against disease.