They didn't "induce" me. I don't like needles. They had me use come contraption named after an animal, and match a workout video. This guy named Tony Little. On the video covers, he looked like a girl, and the pictures wouldn't be appropriate here, but this person:

Anyway, I guess his workout program develops muscle, but it's BORING. I am not a fan of gym workouts. Even wind sprints and running stairs are more interesting.
I don't recall him being in
Iron Man (not that I'm in that class), but I know a lot of the people who are. I doubt Tony Little would last. A lot of those tests are designed for non-athletes. I am no longer an athlete, but my body still remembers when I was. While I don't have the outright speed I had years ago, a few years ago, I foot-raced a college kid who won state in his event. I beat him, and he wanted a rematch. I'd have had to wait a few hours, because my body was drained. I doubt those heart-rate tests are worthwile on anyone who was a competitive athlete.
I don't remember the other details of the discussion, but one of the world athletes stated that the human heart is only good for a certain number of total beats. His theory was that, since his heart rate was much lower, it would last longer. Opposing theory was that his heart rate was much higher during his competitions and training. Data showed that his heart rate never reached what doctors claim is the target heart rate. Even at almost 80 years old, my dad's heart rate doesn't get above 115.