It's not all that different from an intellectual marathon. I'm sure you know the kind, where your brain has been running through whatever text and leaping over whatever challenge so that after however many hours your brain doesn't even feel like it is human anymore and to talk to anyone else will surely be a heady failure but it's all just toast because you're finally finished and everything just seems calmer.
When we put our brains at sport and our bodies too we enter an altogether new plane. And coming down is the satisfaction, the release, the reward, the proof of accomplishment.
If you set out for sport and you achieve it you're happy for the goal and its completion. If you go back the next day you're even happier. That's two days in a row (and the second day when you're just starting exercise is a hard one) I'm doing really well! And then after that it's the same as if you are attacking a new and difficult piece of music, you watch yourself as you improve and the satisfaction becomes even greater physically and mentally.
If secretion from sport blocks things, than the secretion of your mind blocks other things. To accomplish them both is only to become more well-rounded. Does more well-rounded mean more efficient? I'm not sure. Is sport/exercise right for you? I'm not sure either. I only know personally that working my body to the brink relaxes my mind, eases me away from depression, and leaves me in a wonderful stupor of confidence that erases the fear of anything I'm faced with.
The health benefits are obvious and of course if you find the right sport fun is undeniable. There are almost infinite ways to go about it these days that you