Hi. This is my first post so hope I have responded to the correct post.
Yes, Yoga is exercise and I love it, but it is not AEROBIC exercise. There are 3 types of exercise and each is important: Aerobic (walking, biking, eliptical), Anerobic (weight lifting), and Stretching (Yoga). You need all three.
Aerobic exercise increases your pulse and gets all your organs working including your colon. It gets the synovial fluid in your joints flowing to 'oil you up' and help your joints move. It increases endorphins in your brain making you feel better. Aerobic exercise has been shown to decrease your pain (read it on Mayo website) so no wonder all my doctors say 'get your 45 minutes of aerobic EVERYDAY.' I just want to scream if another doctor tells me that. Additionally, you will sleep better if you get some aerobic exercise.
So, just like 'no one thing' is going to cure your IBS but a concert of diet, fiber, teas, etc., no one exercise is all you need.
Yoga does make you feel great and that counts for a lot IMHO. I do find that even if I don't feel like getting out and doing some aerobic exercise in the am, if I will just make myself do it, I feel soooo much better.