If you're just nasal breathing, you're leaning more towards parasympathetic dominance, so you're actually more aware of what is going on. Because when we're stressed out... you can't actually make good decisions—you default to habitual things & responses when we're overloaded.

So, if I'm somebody who's sympathetic dominant, I should probably do something in the morning that probably keeps me a little bit calmer and less reactive so that my day doesn't start off like being shot out of a cannon, and then I end up at 12 or 1 or 2 o'clock falling off of a cliff.