The Perfect Breath | 5.5 Seconds In, 5.5 Seconds Out — Guided Breathing Exercise Follow along with this guided breathing exercise based on the ideal breathing rhythm described in James Nestor's bestselling book Breath: The New Science of a Lost Art. “The perfect breath is this: Breathe in for about 5.5 seconds, then exhale for 5.5 seconds. That’s 5.5 breaths a minute for a total of about 5.5 liters of air.” - James Nestor, "Breath: The New Science of a Lost Art" This simple, powerful pattern of