i was just wondering what are some of the effects of exercising at a high altitude or just living in a high altitude climate. i read that colorado has the thinest people in america per capita. is this because of the altitude? also how high is a high elevation? there is a mountain by my house that is 4,000 feet high and i was thinking about going to the top every now and then to do some cardio. im trying to slim down. any body in here from denver or does anybody know about how elevation effects the body??