Thanks a lot, that's fascinating actually. I had no idea people get that kind of deep effect from it.
I tried it today for the first time. I'm pretty out of shape and it was hard (it was Hatha) to follow along. Certain poses I had zero chance to achieve, but I guess if you keep doing it for months you will get closer. I was sweating like crazy and everyone around me seemed to be too, apart from the instructor. It was pretty comical to see the contrast between your muscles being so tense that your arm is shaking and hearing all that stuff about how you're supposed to relax your neck or whatever at the same time.
I definitely want to do it again, because I'm intrigued. I'm a little concerned about injuries, so I like having a form of exercise that is quite low risk on joints and muscles. Also when I'm swimming almost every day it doesn't feel like I'm doing enough, so having a second thing is nice.