The one-paragraph version
Resonance breathing (also called coherent breathing or resonance-frequency breathing) means slowing your breath to around six breaths per minute — roughly a five-second inhale and a five-second exhale. At this pace, breathing-related heart-rate changes and the baroreflex can become strongly coordinated. That is why resonance-frequency breathing is used in HRV-biofeedback research; the exact rate and subjective effect vary by person.
Why six breaths a minute?
Most adults breathe 12 to 20 times a minute at rest. Slowing to about six does something special: it hits the "resonant frequency" of your cardiovascular system — the rate at which several of your body's rhythms reinforce each other instead of working against each other. Think of pushing a swing at exactly the right moment each time; the effort is small but the effect is large.
Everyone's rate is slightly different
The average resonance rate is around 5.5 to 6 breaths per minute, but individuals vary — some people settle best at 4.5, others closer to 6.5. Clinically, your resonance rate is found by measuring your heart-rate variability across several breathing speeds and seeing which produces the biggest, smoothest oscillations. Without a sensor, a practical approach is to try a few slow rates and notice which feels most comfortable and settling, then refine over time if you track your HRV on a wearable.
What it's good for
Resonance-frequency breathing has been studied in HRV-biofeedback and stress-related research. The literature is promising, but effects vary by population, protocol and outcome, so it is better framed as a training method than a guaranteed route to a particular state.
How to start
Begin with a simple 5-in, 5-out rhythm for five minutes. If that feels rushed, it's fine to start at 4-in, 4-out and lengthen over days. The goal is smooth, effortless, and slightly slower than feels natural — never strained.