4-6
DE Coming to the App Store

A coach for resonance breathing.

4-6 finds the breathing rate your heart responds to most strongly, paces it by sound, and after every session tells you what to change.

It is a skill. This is how you get better at it.

How it works
Inhale

Your heart rate follows your breath. At one rate it does so most strongly, and that rate is yours.

The problem

Numbers are cheap. Knowing what to do with them is not.

HRV apps show you five figures and leave you with them. The alternative has been someone who learned how to read them: a practice, an appointment, an hourly rate.

4-6 does the work in between. It measures, it interprets, and it gives you one concrete thing to do next time.

After a session

And it only grades what can be graded

Every figure gets a range with its source printed underneath, and a verdict in words. No traffic light, no composite score.

RMSSD 66.5ms
3892

Reference: your last 30 sessions, p10 to p90 (n=24)

Within your range.

A little above your usual evening figure.

Swing 35bpm
1441

Reference: your last 30 sessions, normalised for age and sex

Above your range.

The peak sat at 0.10 Hz, exactly on the paced rate.

LF/HF 2.4
no reference range

Not graded.

While the breathing itself sits inside the LF band, this is not a stress ratio. A good session pushes it up.

SDNN 58ms
no reference range

Not graded.

The reference values everyone quotes come from 24 hour recordings, not from ten minutes.

Why it feels different

The pacer is a sound, not a screen

Inhale is one note, exhale a second and lower one, and between them there is an audible turn. Once you have started you do not need the display, and that is why this app exists at all.

All features

Coming to the App Store

For iPhone, in English and German. Starting costs nothing.

Common questions