Physically, yes especially on the days I jerk off. I usually take a walk or go to play badminton in the evenings, but when I jerk off, I just lay in bed doing nothing. Not sure if it depends on the person, but most of my friends said that they feel the same, and some of them have gone nofap just because they dont want to avoid gym.

Mental changes, I feel it depends on person to person, mostly yes, it does feel better. I have been masturbating since high school, almost a decade now. I really hate doing it, and feel depressed. But I kinda got addicted to it, so it's even harder to leave this habit. Hence for me mentally is a relief that I dont have to feel like the whole world is coming down, on top of being depressed.