Exercise Produces Anti-Cancer Hormones in your body called endorphins, so called happy hormones. They have a drug-like effect, even at very low levels: they can actually unblock silenced genes, thus reversing the loss of crucial health messages. In addition, they can greatly reduce stress hormone cortisol levels. Cortisol has been shown to cause severe inflammation in the body linking to two cancer-causing genes; furthermore, cortisol helps cancer spread.