While the word “prevent” can be tricky in medicine—since nothing can provide a 100% guarantee—the scientific consensus is a resounding yes: regular physical activity significantly reduces your risk of developing several types of cancer.

Research from the National Cancer Institute (NCI) and the World Cancer Research Fund shows that higher levels of exercise are linked to a lower risk of at least 13 different types of cancer.

Cancers with the Strongest Link to Exercise:

For some cancers, the evidence is particularly robust. Those who are physically active often see risk reductions ranging from 10% to 42%:

• Colon Cancer: One of the most strongly linked; exercise may reduce risk by up to 24%.

• Breast Cancer: Particularly post-menopausal breast cancer, with reductions around 12–20%.

• Endometrial Cancer: Active women have about a 20% lower risk.

• Others: Significant risk reductions have also been found for cancers of the liver, kidney, esophagus, stomach, and bladder, as well as myeloid leukemia.

How Exercise Fights Cancer

It isn’t just about burning calories; exercise changes your body’s internal chemistry in ways that make it harder for cancer to start or grow:

• Hormone Regulation: It lowers levels of hormones like estrogen and insulin, which are linked to cancer development when they remain chronically high.

• Inflammation Control: Chronic inflammation can damage DNA; exercise is a natural anti-inflammatory.

• Immune System Boost: Physical activity improves the “surveillance” of your immune cells, helping them find and destroy abnormal cells more effectively.

• Digestion Speed: For colon cancer specifically, exercise helps move waste through the digestive tract faster, reducing the time the colon is exposed to potential carcinogens.

• Weight Management: Obesity is a major risk factor for 13 types of cancer; exercise helps keep body fat—which acts as a “metabolic factory” for inflammatory signals—in check.

How Much Do You Need?

To get these protective benefits, health organizations generally recommend:

• 150–300 minutes of moderate-intensity activity (like brisk walking or easy cycling) per week.

• OR 75–150 minutes of vigorous activity (like running or HIIT) per week.

• Strength training at least twice a week, as muscle mass is also linked to better metabolic health and lower cancer mortality.