I do Bikram Yoga (heated yoga).
The first time I did it, I walked into the room and thought, there is no way I am going to get through this. But after I did it I felt so relaxed, like a melting relaxed feeling. It was amazing.
Then I did the 30 day bikram challenge and noticed a lot of definition in my body from that and I noticed I am a lot more relaxed and I can think clearer, just everything feels better. Plus it has helped heaps with my dance classes.
I am a real winter person, I hate the heat and struggle through Summer and Bikram oddly enough still made me feel amazing even though it is done in a 37 degree room.
The only time the heat and everything bothers me is when I am in a packed class and someone tries to squeeze next to me, especially men. And they sweat on my mat and make all these aggressive noises when you shouldnt be pushing yourself hard enough to be breathing heavily. You are supposed to push yourself as hard as you can with a calm breath. I go in the morning so there is a smaller class. I have a real personal space issue... and some people are just so inconsiderate...
What you do today can improve all your tomorrows