# 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. Free guided timer.

## Protocol

1. **Inhale (5.5s)** — breathe in smoothly through the nose for 5.5 seconds. This gently accelerates heart rate via sympathetic activation.
2. **Exhale (5.5s)** — exhale smoothly for 5.5 seconds. The parasympathetic brake engages, decelerating heart rate. Equal ratio is key.
3. **Repeat for 5 minutes** — the 365 protocol: 3 times a day, 6 breaths per minute, 5 minutes per session. Effects last 4–6 hours.
4. **Measure your HRV** — 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?** A mnemonic: 3 times a day, 6 breaths per minute, for 5 minutes. Popularized by Dr. David O'Hare and widely prescribed for stress management.

**Why exactly 5.5 seconds per phase?** The cardiovascular system has a resonant frequency around 0.1 Hz, ~5.5 breaths per minute (5.5s in + 5.5s out). Breathing at this rate maximizes HRV and baroreflex gain. Some people resonate slightly faster or slower (5–7 breaths/min).

**How is cardiac coherence different from meditation?** It's a physiological technique — you mechanically drive heart rate oscillation at a specific frequency. No mantra or mental discipline required; the cardiovascular effect is automatic and measurable.

**Can I measure the results?** Yes. HRV is an objective output. Devices like Oura, WHOOP, or Apple Watch can track HRV before and after a session.

Try it free: https://inhalespace.com/app