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Challenging the ANS

Measuring your ANS at rest is important, but the real test of its health is seeing how it responds—and recovers—from stress. To do this, we use a standardized series of challenges.

The Baseline and Your Balance​

The test begins with a Resting Baseline phase. This measures your ANS in a neutral state and acts as your personal control group.

Here, we measure your Sympathovagal Balance (SB), which is the ratio of your sympathetic to parasympathetic power (LFa / RFa). A healthy, normal SB ratio is typically between 0.4 and 3.0. Autonomic dysfunction or aging can cause this ratio to become imbalanced.

The Three Challenges​

After your baseline is established, you are guided through three maneuvers:

  1. Deep Breathing: You will breathe slowly and deeply at a set pace (e.g., six breaths per minute).

    • What it tests: This is a parasympathetic stimulus.
    • Normal Response: A large increase in your RFa (parasympathetic) power.

  2. Valsalva: You will briefly "bear down" as if exhaling against a closed airway.

    • What it tests: This is a sympathetic stimulus.
    • Normal Response: A sharp increase in your LFa (sympathetic) power and a decrease in your RFa (parasympathetic) power.

  3. Standing (Orthostatic Challenge): You will quickly move from sitting to standing and remain standing still.

    • What it tests: This tests the coordination between both branches to manage gravity.
    • Normal Response: A rapid decrease in parasympathetic (RFa) power followed by a controlled increase in sympathetic (LFa) power. This response is what keeps you from getting dizzy every time you stand up.

What We Look For: Common Dysfunctions​

We analyze your bpm² response to these challenges to identify specific patterns of dysfunction. The most common patterns are:

  • Parasympathetic Excess (PE): This is when your parasympathetic system (brakes) activates abnormally during a sympathetic challenge like Valsalva or Standing. It's like hitting the brakes when you're supposed to be accelerating. PE is often associated with symptoms like fatigue, depression, exercise intolerance, and GI upset.

  • Sympathetic Excess (SE): This is an over-reaction of your sympathetic system (accelerator). This pattern is commonly linked to hypertension, anxiety, pain, and sleep disturbances.

  • Sympathetic Withdrawal (SW): This is the failure of your sympathetic system to activate properly during the Standing challenge. Your body fails to push the accelerator. This is the classic signature of orthostatic intolerance and is strongly associated with dizziness, lightheadedness, and brain fog upon standing.