me and my homie have started lifting weights recently, and he gets faded before each workout. surprisingly, he does great and seems to have no problems. i think it motivates him somewhat, because lifting weights sober is just something that isnt his idea of fun. so he gets high (which is fun) and lifts weights. i have no idea of its effect on the body while working out, but im pretty darn sure its ok. it depends on ur preference. if its too hard, then stop getting high before.