Again great replies. Something that we might want to look at physilogically...
If a person of any age were to start a decent workout regimen some things would start to happen. Your awareness would improve. I know this seems odd, but if you adopt a program of hard work (and lay off the coffee) your body will process adrenaline MUCH better. So in a time of stress your adrenal glands will be kicking at full blast, and the more used to this and less burned out they are the better. Adrenaline will cause you to make mistakes too, and that is why it is good to work under stress during practice.
This has all been general thoughts on my part, and more of a reminder to keep in shape. I try to never assume I did enough work to NOT workout(but I still crash at night sometimes without doing anything, we all do). I will say that if you found me on the street you would realize I am not a fitness nut...I am sturdy built. I got myself a gut and I am not super stacked in arm muscle either. I will say that I regularly win in Jiu Jitsu because I know how to conserve my energy and use energy bursting rather than brute strength. Of course...the guys who regularly beat me do the same thing...but ARE physically fit too(and usually better lol).
Faith Reason Fraternus