RHzBiofeedbackGet RHz free

Breathing practice · Android

Find the breathing pace your body responds to.

Follow the breathing cues. RHz compares your heart's response at different paces, helping you find a starting rhythm you can practice and revisit.

See how it works
Free Android app. Bring your own monitor.

A compatible Bluetooth heart-rate monitor is required. Polar H10 recommended. Check compatibility

RHz trends screen showing observed pacing patterns across sample sessions
RHz session history showing a resonance landscape and sample past sessions
Real app interface · sample data
  • Free to use
  • No subscription
  • No RHz account
  • Session data stays on your device

Why biofeedback?

A timer sets the pace. Your heartbeat adds the feedback.

A timer tells you when to breathe in and out. RHz also reads the small changes between heartbeats, so you can compare your response at several breathing rates.

Your result is a starting point for practice, not a score to chase. It can vary between sessions.

How it works

Connect. Breathe. Review.

  1. 01

    Connect your monitor

    Pair your Bluetooth heart-rate monitor in RHz. Polar H10 is recommended.

  2. 02

    Follow the breathing guide

    Follow the inhale and exhale cues as RHz compares several paces. Keep your breath comfortable.

  3. 03

    Find a pace to practice

    Use your results as a starting point for practice. RHz saves each session on your device.

Inside RHz

See your sessions. Find your patterns.

Choose how you want to practice, then review your sessions and trends. Your history stays on your device.

Explore the RHz app
RHz session setup with posture, session goal, and safety options
Setup. Choose your posture, session goal, and guidance preferences.
RHz history screen with a resonance landscape based on sample sessions
History. Revisit past sessions and the breathing paces you explored.
RHz trends screen showing observed pacing patterns over sample sessions
Trends. See how your recorded breathing paces vary over time.

Real app screens. Sample session data shown.

Find My FrequencyA full sweep compares several breathing rates to find a starting pace.
Quick TuneCheck a narrower range of breathing rates in a shorter session.
Smart StartPractice at a pace that adapts during the session. Past sessions can help guide it.

What you need

Check your monitor before you install.

For measured HRV feedback, choose a monitor that sends the timing between individual heartbeats, often called RR intervals. A beats-per-minute number on its own is not the same data.

Heart-rate-only devices can sometimes connect. RHz estimates their beat intervals, so their feedback is not equivalent to measured beat-to-beat data.

Read the setup guide
Recommended

Polar H10

A chest-strap ECG monitor with dependable beat-to-beat timing for RHz sessions.

Also tested

WHOOP 5.0

An optical sensor tested with RHz. Connection alone does not guarantee measured beat intervals; check what your device broadcasts.

May vary

Other Bluetooth monitors

Look for actual RR-interval support, not just heart-rate broadcasting. Compatibility varies by model.

On your device. In your control.

Your sessions stay on your device.

Your heart-rate data and session history are stored locally in RHz. No account or session-data cloud sync. Export CSV or JSON only when you choose. Website analytics are explained separately in the Privacy Policy.

Read the privacy policyTerms of use

Plain answers

Questions before you start?

What is HRV?

HRV stands for heart rate variability: the small changes in time between one heartbeat and the next. RHz uses this beat-to-beat pattern as feedback while you breathe.

What is resonance breathing?

It is slow breathing at a pace where your heart-rate pattern shows a more coordinated response. RHz helps you explore several rates instead of assuming one pace fits everyone.

Why not simply breathe at six breaths per minute?

Six breaths per minute is a common starting point, but personal resonance can differ. RHz compares your response across guided rates to help identify a more personal starting pace.

Do I need a heart-rate monitor?

Yes. RHz requires a compatible external Bluetooth heart-rate monitor. Polar H10 is recommended. For feedback based on measured HRV, choose a monitor that sends actual beat-to-beat intervals, not just a heart-rate number.

Is RHz free?

Yes. The current Android app is free to use, with no subscription or RHz account required.

Where is my session data stored?

RHz stores physiological and session data on your device. There is no RHz cloud sync for session data. Data leaves the app only when you choose to export or share it.

Is RHz a medical device?

No. RHz is a general wellness and educational tool. It is not intended to diagnose, monitor, treat, cure, or prevent any disease or medical condition, and it is not a substitute for professional medical advice.

RHz for Android

Find your pace. Practice with feedback.

Download RHz, connect your monitor, and start with a guided breathing session.

Read the setup guide
Free for Android. External heart-rate monitor required. Polar H10 recommended.