Marijuana belongs in the same category as alcohol – you need to pull a joker! If however, you are a chronic or very heavy user, then this activity falls into the tobacco side, meaning you should give it up. Studies have shown that one of the long-term effects of chronic or heavy use includes low levels of dopamine (as mentioned above, a neurochemical linked to motivation and reward), in other words, it can stifle motivation. Considering that this workout needs all your attention (and a lot of motivation), it would be contradictory to continue the regular use during the program.