The first, lifting heavy weights is hard for a few seconds then it's like you are fine.
Lifting fairly heavy weight for higher reps is brutal.
LOL, no you are not fine after extremely heavy sets... LOL no way. It's like this, take a powerlifter setting a world record... it may take MONTHS to recover from the
few seconds of exertion. Pumping till you puke is brutal but recovering from low reps is a challenge too. Nervous system takes a beating, mentally you take beating. My training partner set a PR single in the squat last friday, he did nothing else, warming up for 90 minutes, then hit the PR. He has trained for 30 years, competed at an elite level for a long time. He was shaking for a couple of hours after that... felling beat up all weekend.
Told me he needs to downcycle his training for several months to recover. This ain't no guy afraid of hard work, an absolute animal in the gym.
Platz did "deat sets" in the squat for high reps but he could only do this twice a month. A guy who says he trains to the absolute limit twice weekly is not going all out, I guarantee that.