probably not the best thing in the world, but hey i still do it.... (once in a awhile) the only thing i think it would mess up would be cardio... but i suppose everyone now and then won;t have a huge influence on it.... just like everyone esle said moderation is the key... don;t go overboard and you'll save yourself a ton of money... plus i think by smoking every now and than less does the job then those who do it ED...