Have you ever heard of runner’s high? When we run, our bodies produce endocannabinoids, a naturally occurring form of THC, which, when combined with endorphins, produces a sense of euphoria in runners. Well, for veteran smokers, this won’t be the only form of THC released into the bloodstream during exercise. Trainer Joe Holder, drawing on a 2013 study, notes that exercise tends to enhance THC levels in the blood of frequent users. After it’s ingested, the THC from marijuana gets stored in fat, and exercise burns fat. As it burns, THC is released back into the bloodstream, resulting in an actual high.