Exercise & Cancer Immunity
topic
Exercise reduces cancer risk through direct immune surveillance enhancement (NK cells mobilized during aerobic exercise at higher concentrations and with enhanced cytotoxic activity against cancer cells), anti-tumor myokine secretion (SPARC from contracting muscle directly inhibiting colon cancer cell growth), reduction of the pro-carcinogenic hormonal environment of obesity and insulin resistance, and the exercise-induced mobilization of NK cells to tumor microenvironments that may reduce the immune-evasion capacity of established tumors. Exercise is associated with 20–40% reduced risk of at least 13 cancer types in epidemiological studies.
Role
Exercise's anti-cancer immune effects are the most consequential and least-known dimension of exercise oncology — with the majority of cancer prevention messaging focused on diet, tobacco avoidance, and screening while physical activity's direct anti-cancer immune mechanisms receive minimal public attention despite their magnitude. The person who understands that their aerobic exercise session is mobilizing NK cells that specifically target and destroy cancer cells is making a decision to engage their own immune system's cancer surveillance capacity — a reframe that makes exercise feel like a preventive medical intervention rather than a lifestyle choice.