cardiac coherence breathing
your heart's resonant frequency
your cardiovascular system resonates at ~0.1 Hz — roughly 6 breaths per minute. breathing at this rate maximizes the oscillation between heart rate acceleration and deceleration, producing the highest possible HRV. the 365 method: 3 times a day, 6 breaths/min, 5 minutes. the timer counts for you.
Protocol
01
inhale (5.5s)
breathe in smoothly through the nose for 5.5 seconds. this gently accelerates heart rate via sympathetic activation.
02
exhale (5.5s)
exhale smoothly for 5.5 seconds. the parasympathetic brake engages, decelerating heart rate. equal ratio is key.
03
repeat for 5 minutes
the 365 protocol: 3 times a day, 6 breaths per minute, 5 minutes per session. effects last 4-6 hours.
04
measure your HRV
cardiac coherence is one of the few breathing techniques with an objective, measurable output. track HRV before and after with any wearable.
Mechanism
breathing at ~0.1 Hz (6 breaths/min) hits the cardiovascular system's resonant frequency, maximizing heart rate variability and baroreflex gain.
Lehrer & Gevirtz, 2014, Frontiers in Public Health →slow-paced breathing at 6 breaths/min activates the parasympathetic nervous system and increases HRV across multiple physiological measures.
Zaccaro et al., 2018, Frontiers in Human Neuroscience →5 min/day of structured breathing reduced cortisol more than mindfulness meditation in a Stanford RCT with 108 participants.
Balban et al., 2023, Cell Reports Medicine →FAQ
what is the 365 method?
365 is a mnemonic: 3 times a day, 6 breaths per minute, for 5 minutes. this protocol was popularized by Dr. David O'Hare and is widely prescribed by physicians for stress management. the timer automates the counting so you just breathe.
why exactly 5.5 seconds per phase?
your cardiovascular system has a resonant frequency around 0.1 Hz, which corresponds to ~5.5 breaths per minute (5.5s inhale + 5.5s exhale). Lehrer & Gevirtz (2014) showed that breathing at this rate maximizes HRV and baroreflex gain. some people resonate slightly faster or slower (5-7 breaths/min), but 5.5s/5.5s is the most common optimal rate.
how is cardiac coherence different from meditation?
cardiac coherence is a physiological technique — you are mechanically driving your heart rate oscillation at a specific frequency. it doesn't require clearing your mind, focusing on a mantra, or any mental discipline. you breathe at 5.5s/5.5s. the cardiovascular effect is automatic and measurable.
can I measure the results?
yes. HRV is an objective, measurable output. devices like Oura, WHOOP, or Apple Watch can track your HRV before and after a coherence session. many users report measurable HRV improvement within a single 5-minute session.