Back when I tried exercising a lot more for a bit, I actually experienced way more calmness in my life. A part of that might have been that a lot of physical exhaustion brought about unparalleled ease of falling asleep and actually improved the quality of the rest I got.
Another part might have been the fact that for a while it felt like the "baseline" of how much energy I had slightly increased. It was easier to find motivation to do things and I didn't need to rely upon discipline so much as I do now, a zen sort of feeling instead of (as much) procrastination doom and fidgety thoughts. One might also talk of some minute cardiovascular/metabolism improvements as well.
Maybe I should take up more exercise again, it's been a few months and even though I hate actually exercising the benefits, even if relatively minor, are hard to argue against. Just need to find a podcast or something of that sort to keep myself busy and make the experience less mundane.
Though exercise alone won't have any really significant effects, you also need to eat right, take care of yourself in other ways (e.g. sleep schedule, mental state, any addictions or unhealthy habits), so there are a lot of factors to consider.
Disclaimer: these are my subjective and anecdotal experiences.
Regular people workout as well, not just steroid junkies.
One could speculate why folks who are already prone to exercising aren’t necessarily calm folks but that’s just speculation.
If anything, I’m always looking around for empty syringes. They act like they are gonna climb a mountain then come back and try to make me do Beachbody and chalean extreme, then yell at me about what I eat ;)
Not saying exercise is bad, but I do not associate it with calmness. (I’m a healthy dude, you are not hearing this from someone 50 lbs overweight)