I want to avoid positioning this book for athletes, fitness or yoga fans, so do not want any images that will reflect any specific sporting interest—e.g., athletics, cycling, running, or yoga, etc.
The book should rather give the impression that this is a book that can help ANYONE (fit and lithe, or fat and unfit, young or old) understand a) the role that good breathing plays in living a healthy, joyful, vibrant life, and b) how they can improve every aspect of their own lives by retraining their breathing. It must look at all technical.
I understand that this can be a difficult premise to illustrate, and I am open to considering creative ways of reflecting my aims with imagery, as well as without images and simply using strong colours, fonts, typography, etc.
Also, my company colors are green and blue, so it would be nice to have these colors in the cover, but it's not a prerequisite.