Yeah this works in a lot of situations but I've learned it as 4-8-8 like 20 years ago out of some self-help book I don't even remember the name of. Barring the garbage about "yoga mystic woo woo" stuff I've used it to calm down in all kinds of situations that were stressing me out. Not sure about sleep though, as I've rarely had issues getting to sleep, waking up is the tough part.