The question here is it depends. If you are referring to people similar to the those in the show, the answer is no (for all the reasons the others have mentioned). But, if you are referring to individuals who’s lives might depend on their training , for example those in the military (and especially those in Special Operations), then the answer is yes (with a few exceptions). Also, it all depends on your goals, the races/event’s which you are training for and your fitness level and conditioning. I know people who train close to that many hours a day (one way or another) and they are fine, but it takes a lot of time to get to that level and even longer to maintain it…but this is not the norm.