I can't speak to #1 and 2 - while I have my opinions, I have no fact basis to say.

From personal experience, I can vote on both 3 and 4 being true. I can exercise and maybe the outcome is #3 or maybe the outcome is #4! I never know when I start what the outcome will be.....but I have gotten a lot better at identifying the clues and adjusting my activity accordingly. (And then there are other times, when I just feel too weak/heavy to even start!)