breathhackr — live HRV coherence training

READY

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Coherence

Connect a strap to begin

—bpm

RSA swing

—bpm

Your rate

—br/min

Lock

—%

Phase

—deg

🔊 70 Tartini + drone

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Live metrics

Pace

Breath vs heart rate at resonance the red line rides the shaded hump — no lag

Coherence last 10 min · dashed line is the 85 target

RMSSD & SDNN time-domain HRV, 60 s window

🔊 70 pacer tone

Sound bed

Rebuilt from the stack that scored best across 59 logged trials: a pacer tone sweeping 55→82 Hz with the breath, a Tartini pair (1100 + 1155 Hz) whose phantom difference tone lands at 55 Hz, and a sustained 55 Hz drone — synthesised live, no files, no loop seams. Use headphones or a speaker with real low end.

What these mean

Coherence — the share of your heart-rate variability sitting at your breath rate. It climbs as the beat-to-beat pattern collapses into one clean wave. Above 85 is the region worth aiming for.

RSA swing — how far heart rate travels between peak and trough within one breath. This is the thing you're training.

Phase — how far heart rate trails the breath, in degrees of the cycle. Near 0° means heart rate rises and falls in step with your breathing, which is the definition of breathing at your resonance frequency. It settles faster than any time-domain HRV number.

Lock — how close your measured rate is to the pace you picked. Low lock with high coherence just means you've drifted to a different rate, which may well be your real resonance frequency today.

Everything runs in this tab. Heart data is never uploaded or stored — there is no server, no account, no analytics.