My question was more out of curiosity about the why choose altitude training (especially if you are using a tent) vs not. I was surprised about the controversy over this in my local (midwest) running group. Over 50% saying it was dangerous to use an altitude tent citing a 1/1000 scenario. Frankly, my main reservation is simply cost and lifestyle impact.
Huh, I'm out of the loop on this controversy. I really hadn't thought that far ahead. But I did note, sadly, that Pam Smith used an altitude tent training for her win at Western States this year. WS is my top running priority for 2014, and I want to do everything I can to run it well. But I also have reservations about lifestyle impact. I guess what really bothers me is that this is a case where whoever is willing to spend more and suffer more inconvenience gains an advantage. But it's not like training, which is more "honest". It's just a stupid arms race. Can't we all agree to just not do to that, and save everyone the hassle? But then those who live at altitude have an advantage. Oh well.
Anyway, what is this supposed danger?
I don't recall exactly but one person was talking about how their friends using it developed blood clots, several other people jumped in citing people they "know" that had health issues they believed were a result from stressed immune system. I personally haven't seen anything I would call fact to create this level of alarm, but the group "think" dynamic often goes in the face of facts...