Actually the GP is incorrect. It's pretty well understood [1] these days that your body is like a "cup" that can only take a certain amount of stress before it starts getting counter productive. Mental stress and center-nervous-system stress (what weight training does) both contribute so if you already have a lot of one you're forced to have less than the other or everything suffers.
[1] I'm not in a position to hunt links but lookup "Alan Thrall stress" on youtube.
Many thanks, this seems to be pretty close! Anyway, do you know any way to increase the "stress threshold", so that I can withstand more mental + physical stress? Mental stress is given by work, and one doesn't want to look flabby either but rather ripped without getting ill/fatigued etc. I understand a lot of this is genetic, though I am sure there are some ways to help body with it.
Well, this is all new to me as well but the way I've seen it presented (from multiple sources) it seems to be person-specific. If there is a way to increase you "cup size" either I haven't yet seen it (wouldn't be surprising) or it isn't yet known.
Oh well, I guess it's trial and error then. I was actually doing 5 minute cold showers for a year, alongside HIIT/strength training/cardio and bleeding edge mental work, and I guess I was too optimistic I could handle it and went over my limits (which seem to be pretty high already but still firmly in place...)
[1] I'm not in a position to hunt links but lookup "Alan Thrall stress" on youtube.