Short sessions of high intensity exercise may limit colorectal cancer (CRC) growth. Researchers recruited 20 patients who survived CRC and split them into an acute group who completed a single session of high intensity interval training (HIIT) (serum samples were collected at baseline and at 0 and 120 minutes after exercise) and a chronic group who participated in 12 HIIT sessions over 4 weeks (resting serum samples were collected before and after the 4 weeks of training). In addition, cells from the acute group were incubated and analyzed for number of cells present. Results showed significant increases in serum interleukin-6 & 8 as well as TNF-alpha – cytokines that are associated with cancer growth reduction. But these increased cytokine levels were only observed in serum collected immediately after exercise and not in those collected 120 minutes post-exercise. Journal of Physiology

→Takeaway: Past studies have shown a link between exercise and CRC survival. Researchers who conducted the study believe that repetitive exposure to the acute effects of high intensity exercise could help explain this link.