Observed arrival · 2026-08-30
4–6, the resonance-breathing coach
An iPhone breathing app that finds a user’s strongest heart-rate response, guides practice with sound, and explains what to change after each session.
Field notes
The product combines paced breathing with session interpretation: it searches for the breathing rate that produces the strongest heart-rate response, then compares later readings with personal reference ranges. The example uses the last 30 sessions, reports a sample size of 24, and flags a 0.10 Hz peak as exactly matching the paced rate. Its audio cues separate inhale and exhale, allowing practice without watching a screen.
Observed signals
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Editorial observations of this landing page, not a rating.
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