To start here are some symptoms of chronic mouth breathing: 1. Often out of breath and fatigued 2. Increased anxiety 3. Prone to asthma and exercise induced asthma 4. Dry mouth in the morning 5. Getting sick easily 6. Sinus issues, stuffy nose 7. Frequent coughing or throat clearing 8.  Feeling of oxygen...

This is a fascinating and vital read if you are interested in health and endurance. "Oxygen Advantage" by Patrick McKeown is available as a audiobook as well as paperback. The book and it's research makes the case that we tend to over-breath. That we get rid...