[frubar]

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.

[bitL]

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.

[frubar]

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.

[bitL]

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...)