Learn · HRV biofeedback

Feedback turns a breathing timer into a measured practice.

RHz uses live beat-to-beat timing from compatible external hardware while you follow guided breathing rates.

What HRV means here

Heart rate variability describes the small changes in timing from one heartbeat to the next. During a guided session, RHz uses those timing changes as feedback rather than relying on heart rate alone.

What you can see in RHz

The app displays live beat-to-beat feedback during sessions and saves completed sessions on your device for later review.

  • Guided full and quick resonance sweeps
  • Adaptive practice sessions
  • Live RMSSD, SDNN, heart rate, and beat-to-beat information
  • Session history, resonance landscape, and frequency trends
  • Manual CSV and JSON export

Local session data by design

RHz does not require an account or cloud sync for session data. Physiological and session data stays on your device unless you choose to export or share it. Website analytics are separate and explained in the Privacy Policy.

Continue learning

Review the setup guide, compare ECG and PPG sensors, or return to the RHz overview.

Ready to begin?

Install RHz on Android, connect a compatible monitor, and start with a guided breathing session.