I found that my "edge" is jogging. When I increased my walking speed, from walking to jogging, I became breathlessness. When this breathlessness happens I reduce my speed and back to walking again.

I utilize a personal Oxygen Saturation meter to back up my own common sense. How do I feel? At first, I was quite weak and had low capacity and endurance. I slowly built my endurance and capacity. Bit by bit, day by day.

I recently resumed swimming (I live in Hawaii, and so it was a huge loss, at first) for the first time in ages, and was shocked to discover how able I was. I didn't push myself, I went slowly and enjoyed it. Swimming allows me to use my muscles differently, such as side stroke, which extends the arm, shoulder, and maximizes the side stretch of the rib muscles.

pacing your self is the key. I am slow on steep hills, but I am relentless. Use it or lose it really applies to lung and body function.

I realized that it was hard to evaluate my capacity, and I am used to pushing my limits.

So I invested, first, in a tiny Tinke unit from Zensorium, which connects to a smart phone. It was very helpful to have an objective answer to my oxygenation. (When it was under 94, I needed to modify something...my position, my breathing, my activity, or time for the inhaler and coughing.)

Now there is an APP for the iPhone, which uses the camera flash to read the circulation through your fingertip. It gives both O2 saturation rates and heart rate.

If you aren't getting enough oxygen, your heart will beat a lot faster to compensate and push oxygen through to the tissue and your brain. Shallow breathing exaggerates this.

Yoga teaches you to pay attention to your breath, and USE your diaphramatic muscles to breathe more efficiently and effectively. If you are anxious or panicky about your breathing, you will hyperventilate, fast and shallow. Learn as much as you can