I did yoga for a while a few years ago. I forget the name of the specific type that I did, but they kept the studio at 115 degrees. Each session was about an hour and fifteen minutes, and by the end of the session everyone was literally dripping with sweat. I never thought I'd be able to get such a good workout just by stretching.
make sure your instructor is certified and has a good industry reputation. from what i've read there are lots of quacks out there that will hurt you more than help you.
Speaking of running, I just took up running and I was wondering if there are any breathing tricks or stretches I should know about?
Also, what is the best way to build endurance? I started about 2 months ago and I pretty much top out at 1.5 miles before I feel like I'm gonna hurl. I run about 3 times a week.