I think you're being a bit ignorant. When I blaze a joint before I play basketball I always perform better. The focus it brings me on the court is great, generally speaking weed is also known as a vasodilator which means it expands your blood cells allowing for better blood circulation. I run 6 to 8 km everyday and when I blaze I usually get a better time and feel better than when I don't blaze. Mind you if I never smoked weed before and I smoked for a week or something I'm sure it would have negative impacts on my cardiovascular system as my body and lungs would not be use to the smoking aspect.
