Vagal Sense: HRV & Vagus Nerve

Vagal Sense organizes and documents heart rate variability (HRV) in professional health practice.

WHO IT IS FOR

Physiotherapists, osteopaths, physicians, psychologists and exercise professionals who already use HRV in practice — or who want to start doing it rigorously, without an improvised spreadsheet.

If you already measure resting heart rate and write it in a notebook, Vagal Sense is the next step: the same gesture, with a record that accumulates and a comparison that holds up.

WHAT VAGAL SENSE ORGANIZES

• Response patterns (phenotypes F1–F8) — the pattern observed in that session, with context, instead of a number on its own. It changes from session to session: an informative trend, not a fixed label for the person.
• Structured record across 8 domains — consistent notes per person, session after session.
• History per person — how things evolve over time, on your phone.
• Mobile-first — built for the flow of a session, not for a desktop in the office.
• Guided practices at many paces — including your own: create custom tasks in the library, with a guided breathing rhythm.
• Resting breath pause and orthostatic test (30:15 ratio), each with its own document.
• Two PDF reports: one for the person you work with, in plain language, and a technical one for you.

WHAT A SESSION LOOKS LIKE

You connect the strap, record a few minutes at rest and follow the tachogram — the beat-to-beat curve — in real time. If you want, you run guided breathing right there, with visual, audio and haptic support, and watch the response happen on the curve itself. At the end, the app computes RMSSD and SDNN, saves the summary with your note, and suggests practices grouped into three tracks: Restoration, Rhythm and Expansion.

Next time, today's session sits side by side with the one from three weeks ago.

HRV, THE VAGUS NERVE AND BIOFEEDBACK IN PRACTICE

The vagus nerve is the main pathway of the parasympathetic branch of the autonomic nervous system, and the variation between heartbeats is the most accessible window onto it. That oscillation follows your breathing — inhaling speeds the heart up, exhaling slows it down — and is known as respiratory sinus arrhythmia, one of the most studied ways to observe vagal tone.

Vagal Sense does not replace your reasoning: it records what you observed, in a form that lets you compare today's session with the one from three weeks ago. Guided breathing and real-time biofeedback are available for use during a session.

NO HARDWARE REQUIRED

Vagal Sense works without a sensor. When you want chest-strap accuracy, the app uses the Polar H10 — the same real RR intervals as Vagal HRV.

Watches and rings estimate heart rate with light (PPG): they measure the average well and the exact interval between beats poorly. Since HRV is made of precisely those intervals, a chest strap is what sustains a record you can compare over time.

YOUR DATA STAYS ON YOUR DEVICE

No account, no server, no cloud. The records of the people you work with never leave your phone — on the Play Store, our Data Safety section declares "no data collected".

You export PDF reports whenever you need them, and you can create a full backup as an AES-256 encrypted file protected by your own password. Since we keep no copy on any server, that backup is what protects your history when you change devices — make one regularly.

BUILT FOR YOUR DAY

• Fully offline — nothing depends on a connection in the middle of a session
• No account and no sign-up to get started
• Available in English, Portuguese and Spanish
• Light and dark themes

IMPORTANT NOTICE

Vagal Sense is intended for informational and educational purposes in professional practice. It is not a medical device, it does not diagnose and it does not replace professional assessment — the results should not be used as the sole basis for clinical decisions.

Polar and Polar H10 are trademarks of Polar Electro Oy. This app is not affiliated with Polar Electro Oy.