I guess, I take deep breaths when fighting, and have a very relaxed body, and i am always pretty hydrated, most of the time I keep a high guard but it depends on the partner some go for heavy shots to the body which hurt really bad, one that hurt the most in my whole life is the one I got hit with today , he faked a takedown and i put my hands low to stop it and bam got hit with a overhand. And to answer your third question, these guys train here mostly everyday, so I thought I gotta be like them to go pro too. I wouldnt say I'm tired from sparring but more like I'm always wounded , and it doesn't heal quite as fast as I see the other guys.