Last night in our third Exploring Meditation class, I was asked whether, in meditation, it was best to breathe through the nose or a combination of nose (inhalation) and mouth (exhalation).
This morning I was reading How God Changes Your Brain and was astounded to find just the perfect answer to this question (similar to what I shared last night, but backed by research).
From How God Changes Your Brain: Breakthrough Findings from a Leading Neuroscientist by Andrew Newberg M.D. and Mark Robert Waldman (Chapter 9: Finding Serenity):
"In general, when meditating, we recommend that you breathe through your nose. Why? It turns out that nasal breathing increases the release of nitric oxide in the body, and this improves the functioning of your lungs and circulatory system. Increased nitric oxide may also assist in the lowering of anxiety, especially in socially intense situations. Nasal breathing, like yawning, also serves to keep the internal temperature of the brain in balance".