I've taught most of my clients breathing exercises for the past 5-6 years. It's unnecessary to take it to the level of a formal pranayama practice to make fairly significant differences in physiological state, from which most everything else derives.
The "coherent breathing" work that popped up sometime in the last ~15 years is pretty interesting, too.
The "coherent breathing" work that popped up sometime in the last ~15 years is pretty interesting, too.