The Yoga “ohm” supposedly massages the central nervous system. Mine needs a good massage. Deep breathing can do the same. A slow inhale, a slight hold, then a slower exhale and a pause. That’s called “square breathing”. When you inhale through the nose, your diaphragm should expand and when you exhale, contract. Most people breathe backwards. And most of us only use the top third of our lungs. So what exactly does deep breathing do that calms the nerves? It sends oxygen to the areas of our brain which control the release of stress signals. Simply put, it can thwart a major meltdown.