I live and work pretty close to sea level and I've never really trained at high altitude. A friend of mine recently moved to a town in the mountains (~7000ft) about 2.5 hours from me. If I were to go and train with him on weekends, would I get any "altitude training" benefits from just running there 2 or 3 days at a time? Or do you have to train there consistently for several weeks for it to make any difference?