Breathing techniques that increase oxygen intake can increase alertness and deploy norepinephrine, leading to greater arousal.

“If your exhales are longer and more vigorous than your inhales, you're going to get calm down. If your inhales are longer and more vigorous than your exhales, you're going to become more alert.”

“in response to stress it's really if you want to be more alert increase the Vigor and duration of your inhales if you want to be more calm increase the duration of your exhales”

“if you bring more oxygen in by making your inhales deeper and longer you will become more alert you'll start to actually deploy norepinephrine if you breathe very fast”