# Resonance: HRV Biofeedback

> Resonance: HRV Biofeedback (iPhone/iPad app by Groma Apps.)

- Source: https://appshunter.io/ios/app/resonance-hrv-biofeedback/id6812053481 (this page in markdown: same URL + `.md`)
- Developer: [Groma Apps](https://appshunter.io/developer/6812053483)
- Category: Health & Fitness
- Price: Free with in-app purchases
- Age rating: 4+
- Requires: iOS 15.0 · 60 MB
- Languages: American English, French (France), German (Germany), Japanese, European Spanish
- Released: 2026-10-02
- Data updated: 2026-10-04
- User reviews in markdown: https://appshunter.io/ios/app/resonance-hrv-biofeedback/id6812053481/reviews.md

## What is Resonance?

Most breathing apps give you someone else's breathing rate. Resonance: HRV Biofeedback finds yours.

Your resonance frequency — the breathing pace that maximizes your heart rate variability (HRV) — is unique to you. It's usually 4.5 to 6.5 breaths per minute, but the exact rate is personal. Breathing there maximizes respiratory sinus arrhythmia (RSA) — the natural rise and fall of your heart rate with each breath. A generic pace like "6 breaths per minute" misses it for most people.

Resonance uses live HRV biofeedback to measure your actual resonance frequency, then trains you at that exact pace.

START WITH THE WATCH YOU ALREADY OWN

Turn on heart-rate broadcast on your Garmin, Polar, Samsung, or Fitbit watch and you're ready — no extra hardware to buy. Any Bluetooth chest strap or arm band works too (Polar H10, Garmin HRM-Pro, Wahoo TICKR, and more).

You only need a sensor twice: for the 12-minute assessment that finds your frequency, and whenever you want live coherence biofeedback. Every daily practice session after that runs at your stored pace with no sensor at all.

FIND YOUR FREQUENCY IN ABOUT 12 MINUTES

A three-phase protocol — ASSESS, REFINE, HOLD — scores candidate breathing rates against your live HRV using the published Shaffer & Meehan (2020) six-criteria coherence model, then locks in your personal resonance frequency and refines it each session.

LIVE HRV BIOFEEDBACK, NOT A BLACK BOX

• Real-time heart-rate trace and frequency spectrum during every session
• All six Shaffer coherence criteria live — peak LF power, single-peak dominance, LF concentration, peak height, SDNN, RMSSD
• Watch your heart rate turn into a smooth, sine-like wave as heart coherence builds

TRACK REAL IMPROVEMENT

• Session Quality Score (0–100) after every session — time in coherence, RSA amplitude, and consistency, scored separately
• Full session history with HRV trend charts for coherence, resonance, RMSSD, breathing pace, and heart rate
• Shareable session cards with your actual heart-rate trace

BUILT FOR DAILY PRACTICE

• A calm breath pacer with visual, audio, and haptic cues for eyes-closed sessions
• 10 sound packs and a breathing exercises library with multiple session modes
• Custom inhale/exhale ratio and practice reminders

PRIVATE BY DESIGN

Your heart-rate data never leaves your device. No account, no cloud, no sign-up. Everything works offline.

FREE TO START

The full resonance assessment and unlimited practice are free. Resonance Pro adds the adaptive pacer, full breath history, the complete resonance score, sound packs, and the exercises library — available monthly, annually, or as a one-time lifetime purchase.

THE SCIENCE

Built on 30+ years of peer-reviewed HRV biofeedback research. The engine uses Lomb-Scargle spectral analysis, the HeartMath coherence ratio, and the full Shaffer six-criteria model, all computed on-device.

Resonance: HRV Biofeedback is a wellness and breathing-training tool, not a medical device. It does not diagnose, treat, or prevent any condition; supported heart-rate sensors are consumer fitness devices, not medical hardware. Always seek a doctor's advice in addition to using this app, and before making any medical decisions.

References:
Task Force (1996)
Lehrer et al. (2000)
Shaffer & Ginsberg (2017)
Shaffer & Meehan (2020)

COMPATIBLE DEVICES

Any consumer Bluetooth 4.0+ heart-rate sensor using the standard Heart Rate Service — smartwatches, chest straps, and arm bands.

WHO IT'S FOR

Anyone training heart coherence and resonance frequency breathing as a daily practice. First-timers who want a guided daily practice that works, athletes using breathwork to recover and downregulate, and researchers who want live spectral analysis, RMSSD, SDNN, and raw R-R export. No prior HRV knowledge needed.

Resonance frequency breathing. HRV biofeedback. Measured, not guessed.

Terms of Use: https://heartresonance.app/terms.html · Privacy Policy: https://heartresonance.app/privacy.html

## Pricing and in-app purchases

Base price: Free.

**Subscriptions**

| Subscription | Price | Period |
| --- | --- | --- |
| Resonance Pro - Monthly | $2.99 | per month |
| Resonance Pro - Yearly | $14.99 | per year |

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| Resonance Pro — Lifetime | $29.99 | one-time |



## Version history (last 1 release)

### 1.0 — 2026-10-02

No release notes.

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## Related topics

[biofeedback labs](https://appshunter.io/ios/topics/biofeedback-labs)

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-10-04.*