" Breathing is a favorite "sleep hack" of mine. Counting out a few slow breaths is one of the techniques I use when I'm having trouble falling asleep..the 4-7-8 method..you inhale quietly through the nose for four counts, hold for seven counts, and exhale with a whooshing sound through the mouth for eight counts. "

― Arianna Huffington , The Sleep Revolution: Transforming Your Life, One Night at a Time