I have a friend who is a legal medical marijuana user and an intermediate level distance runner. She probably inhales a quarter ounce a month and to my knowledge does not eat or take her medicine via any other means. She claims to have experienced no negative effects on her running from her medication and on the eve of races that resulted in personal best times (which keep getting better), she took her medicine as prescribed. Although, she apparently did not take it before or during any races. Is this possible? Have their been studies related to marijuana smoke and running? Which is worse on your running, tobacco or marijuana? Or does it improve your running? Kinda like that study that found marijuana smoke to have a mild preventative effect against lung cancer.