I don't really have an answer to your question, but is Yoga considered cardio? It was my understanding that you had to increase your heart rate and keep it elevated for at least 20 minutes to consider the excercise you are doing as cardio.

I've done some beginning Yoga excercises, they are wonderfully relaxing, and I love the stretching, but I'm not sure I would think of them as cardio or aerobic type excercises.

I know you breathe a lot with Yoga, but it is like really relaxed breathing, do you breathe hard? Is your heart pumping? Unless it is, I wouldn't consider the excercise to be "cardio" and I would figure that you should be doing cardio that does that to you and just call your Yoga class "recreational" excercise.

He does allow for recreational excercise on top of whatever cardio you do in the BFL book.