kazbah

there are a few different types of yoga...named after the indian yogi who created them
hatha...gentle flowing yoga with focus on breath
iyengar...dynamic yoga postures with the use of props (to assist in getting work in the pose for beginners)...this is what I practise and teach
astanga...dynamic yoga in a series of postures
bikram...yoga in a warmed room

Hollo

I do agree that some yoga does not increase the heart rate (hatha for eg)...but I assure you that any dynamic yoga practise works you enough to work the heart rate and cause you to break out in a sweat and get breathless even

xx yogababy