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Measuring the ANS

Measuring the Autonomic Nervous System (ANS) has historically been difficult and invasive. For years, the only non-invasive method attempted was Heart Rate Variability (HRV).

HRV simply measures the timing between your heartbeats, usually in milliseconds (ms).

The Problem with HRV​

The critical failure of using HRV-alone is that it provides a mixed and confounded measure of your two autonomic branches. It cannot tell you what is causing a change.

If your HRV score changes, what does it mean?

  • Did your sympathetic system (accelerator) just double? This could be a sign of preclinical hypertension or anxiety.
  • Or... did your parasympathetic system (brakes) just get cut in half? This could indicate a serious cardiovascular risk.

HRV-alone cannot distinguish between these two very different scenarios. It's an ambiguous number.

The Solution​

The fix is to add a second, independent signal: your respiratory activity. By analyzing your breathing and heart rate together, we can un-mix the signals.

Here is how our method works:

  1. We track your breathing pattern to find its Fundamental Respiratory Frequency (FRF). This frequency is the unique signature of your parasympathetic (vagal) activity.
  2. We precisely measure the power of this signal in your heart's rhythm. We call this the Respiratory Frequency Area (RFa). This is your pure Parasympathetic measure.
  3. We then measure the remaining power in the low-frequency band. We call this the Low Frequency Area (LFa). This is your pure Sympathetic measure.

A New Vital Sign: bpm²​

This method introduces a new vital sign. Instead of measuring time (milliseconds), we measure power. The unit for this power is beats per minute squared (bpm²).

Think of LFa and RFa as a stereo signal for your body's control system.

  • Your Heart Rate (HR) is just an average (e.g., 60 bpm).
  • Your Instantaneous Heart Rate (IHR) shows the raw beat-to-beat changes.
  • Your LFa and RFa in bpm² show the strength or tone of your accelerator and brakes.

This same assessment can be performed in a clinic, often requiring a tilt-table test or other specialized equipment. Our technology makes it possible to perform this advanced measurement simply and non-invasively.