Authors: Peter A. Biro; FrédéricThomas; Beata Ujvari; Christa Beckmann

Source: Trends in Cancer (June 2020)

Brief summary of the paper:

Physical activity substantially reduces the risk of developing cancer. As such, exercise promises to be a powerful preventative measure against cancer.

However, if we are to ‘prescribe’ exercise, we should identify how and why exercise affects cancer risk to provide informed prescriptions.

We find that high energetic capacity is both a cause and consequence of high sustained activity levels, both at a genetic level and due to training effects.

High energetic capacity in turn can increase immune responses and reduce incidence and progression of cancer, and this effect can be independent of activity. Thus, exercise may reduce cancer risk via increasing one’s energetic capacity for immune function.

In light of this potential mechanism, prescriptions for exercise might consider those likely to increase one’s energetic capacity, which may differ among individuals given innate differences in our ability to generate energy on a sustained basis.

Increased physical activity reduces cancer risk in humans, but why this whole-organism attribute reduces cancer remains unclear. Active individuals tend to have high capacity to generate energy on a sustained basis, which in turn can permit greater immune responses crucial for fighting emerging neoplasia.

Thus, we suggest energetic capacity as a potential mechanism to explain the activity–cancer link, given that humans are intrinsically (not externally) energy limited.

Human and rodent studies show that individuals with high energetic capacity mount greater immune responses and have lower cancer incidence; these trends persist after controlling for actual physical activity, supporting a direct role of energetic capacity.

If true, exercise efforts might best target those that increase one’s energetic capacity, which may be both individual and exercise specific.