David,
I had the good fortune to meet you in a recent workshop. I'd be very grateful for your advice.
I am prompted to ask for your help having had a heart attack 3 months ago followed by a surgery. I've been a student of Iyengar yoga for 5 years and 3 years ago discovered the joys of Ashtanga, slowly building a regular practice 3-4 times a week while also pursuing a basic Iyengar teacher training. I'll be 54 years old in January. My herbal doctor is also concerned about the heat created by the Ujjayi breath.