Exercise as Cancer Medicine: How Physical Activity Prevents and Treats Cancer

Exercise represents a paradigm shift in cancer care, transitioning from supportive therapy to essential medical intervention. Dr. Kerry Courneya's extensive research demonstrates that structured physical activity fundamentally alters cancer biology, treatment outcomes, and survival rates across multiple cancer types.

For prevention, exercise ranks as the fourth most important lifestyle factor after smoking cessation, weight management, and alcohol reduction. The protective effects follow a clear dose-response relationship, with benefits plateauing around 300 minutes of moderate-intensity exercise weekly. Remarkably, exercise reduces cancer risk even in high-risk populations including smokers and obese individuals, suggesting mechanisms beyond weight control.

During treatment, exercise serves multiple critical functions. It helps preserve muscle mass, which directly correlates with survival outcomes, as cancer-related muscle wasting (cachexia) significantly increases mortality risk. Exercise also enhances treatment tolerance and may directly combat cancer through increased blood flow shear stress that destroys circulating tumor cells. Pre-diagnosis fitness acts as crucial 'prehabilitation,' preparing patients for intensive multimodal treatments that often include surgery, chemotherapy, radiation, and newer immunotherapies.

The research emphasizes that structured moderate-to-vigorous exercise provides superior benefits compared to general daily activities. Both aerobic exercise and resistance training offer distinct advantages, with resistance training becoming increasingly important for maintaining the muscle reserves essential for surviving cancer treatments. This evidence positions exercise not merely as lifestyle medicine, but as a fundamental component of comprehensive cancer care that influences prevention, treatment tolerance, and long-term survival outcomes.