I periodically receive the ChiRunning newsletter and recent letter contained interesting segment on breathing.
I was particularly interested in paragraph B. Some time ago I perceived that my quick bite of air was only entering the upper portion of my lungs and started to focus on drawing air deeper down into them. With a little practice, there was a noticeable improvement in my swimming breathing capability.
No panacea, but a definite improvement. I thought paragraph C was also insightful.Take a look and draw your own conclusions.