You’ve been to your primary care doctor. Your labs are “normal.” Your imaging looks fine. But something still feels wrong. Maybe you’re exhausted all the time, your heart races for no reason, you get dizzy when you stand up, or your body just doesn’t seem to regulate itself the way it should.

If that sounds familiar, there’s a good chance no one has ever taken a close look at your autonomic nervous system.

At Nexus Neuro in Carmel, Indiana, we use a specialized tool called the Nerve Express to do exactly that. It’s one of the most comprehensive autonomic assessments available in a clinical setting, and for many of our patients across Carmel, Westfield, Fishers, Zionsville, Noblesville, and the greater Indianapolis area, it’s the first time they’ve ever gotten a clear picture of how their nervous system is actually functioning.

Here’s what it is, how it works, and why it can be a game-changer for your care.

Your Autonomic Nervous System: The Control Panel Nobody Checks

Your autonomic nervous system (ANS) is the part of your nervous system that runs in the background. It handles the things you don’t have to think about: your heart rate, breathing, digestion, circulation, temperature regulation, and how your body shifts between states of rest and action.

It does this through two branches that are always in conversation with each other:

The sympathetic nervous system (SNS) is your gas pedal. It activates your “fight or flight” response, speeding up your heart rate, sharpening your focus, and diverting blood flow to your muscles when you’re under stress or demand.

The parasympathetic nervous system (PSNS) is your brake pedal. It governs your “rest and digest” state, slowing things down, promoting recovery, and keeping your heart rhythm steady.

When these two branches are in balance, your body adapts seamlessly to the demands of your day. When that balance breaks down, almost everything can feel off. And yet, standard medical testing rarely looks at this system directly.

That’s where the Nerve Express comes in.

What Is the Nerve Express?

The Nerve Express is a fully automatic, non-invasive, computer-based system designed for the quantitative assessment of the autonomic nervous system based on heart rate variability (HRV) analysis.

In plain terms: it measures the tiny variations in the time between your heartbeats. Those variations aren’t random. They’re actually highly meaningful data points that reflect how well your sympathetic and parasympathetic systems are communicating, adapting, and functioning in real time.

The heart rate variability analysis is based on measuring variability in intervals between R waves, or “RR intervals,” using proprietary algorithms and a method grounded in artificial intelligence research.

What makes this technology stand out is its ability to go beyond a basic HRV readout. Nerve Express is the first and only system to solve the problem of SNS and PSNS quantification, pinpointing the precise relationship between your sympathetic and parasympathetic activity rather than giving you a vague score.

The algorithms behind Nerve Express have been developed over more than two decades, with early clinical studies conducted at Cornell Medical Center and Columbia University. (Nervexpress)

How the Test Works: Two Key Assessments

The Nerve Express uses a battery of tests designed to challenge your autonomic nervous system in different ways and observe how it responds. It uses a convenient chest strap with a Bluetooth transmitter to collect RR interval data during the tests, making it completely non-invasive and comfortable.

1. The Orthostatic Test

The orthostatic test assesses your autonomic nervous system and physical fitness level based on changes in posture.

Here’s what happens: you start lying down, then you stand up. Simple enough. But for your autonomic nervous system, that positional shift is a significant challenge. Your body has to quickly redistribute blood flow, adjust your heart rate, and maintain enough circulation to your brain to keep you from feeling dizzy or faint. Failure of the heart rate to respond appropriately can be a sign of autonomic dysfunction.

The Nerve Express captures this entire response in detail, measuring how smoothly your ANS makes that transition and whether your sympathetic and parasympathetic branches are coordinating the way they should.

It can also evaluate your Fitness Score during this test, assessing adaptability level and functional capacity across 91 distinct physiological states.

2. The Valsalva Maneuver Combined with Deep Breathing

This is one of the most informative parts of the test.

The Valsalva maneuver combined with deep breathing is used to assess the ANS and to reveal the hidden abilities of autonomic function, helping distinguish between chronic and temporary abnormalities.

The Valsalva maneuver involves exhaling forcefully against resistance for about 15 seconds, similar to the pressure you might feel bearing down. It creates a predictable sequence of cardiovascular changes that reveal a great deal about both sympathetic and parasympathetic function.

Heart rate variability is one of the most reliable measures for assessing autonomic nervous system function, and this is especially true when controlled maneuvers like the Valsalva maneuver and deep breathing are employed. The high reproducibility of these tests makes them invaluable tools for confirming normal ANS operation or identifying autonomic dysfunction.

Deep breathing is paired with this maneuver because it directly activates your vagus nerve (a key player in parasympathetic function) and reveals how well your PSNS is able to respond. If there’s a disconnect between what your body should be doing and what it’s actually doing during these maneuvers, the Nerve Express catches it.

What We’re Looking For

When we review your Nerve Express results, we’re looking at the balance between your SNS and PSNS, how well your ANS adapts to physical challenges, whether your nervous system is in a chronic state of overdrive, underfunction, or imbalance, and how your autonomic status has shifted between visits.

This kind of specificity matters. “Your nervous system seems a little off” isn’t useful information. Knowing exactly where the dysfunction lies, and in which direction, is what allows us to build a targeted care plan rather than just guessing.

Who Should Consider This Test?

The Nerve Express autonomic assessment is a valuable tool for patients dealing with a wide range of conditions that involve nervous system dysregulation. If any of the following apply to you, this test may be an important piece of your evaluation:

• Dizziness or lightheadedness, especially when standing
• Heart palpitations or irregular heart rate
• Chronic fatigue that doesn’t improve with rest
• Brain fog and difficulty concentrating
• Anxiety, chronic stress, or feeling “wired but tired”
• POTS or dysautonomia
• Post-concussion symptoms
• Neuropathy or unexplained tingling and numbness
• Difficulty recovering from illness or exercise

These are all conditions where the autonomic nervous system plays a central role. And they’re conditions that conventional testing often misses entirely.

Getting to the Root, Not Just the Symptom

At Nexus Neuro in Carmel, Indiana, we believe that understanding your nervous system is foundational to any lasting improvement in your health. The Nerve Express gives us objective, quantifiable data about how your autonomic nervous system is functioning, so we can stop guessing and start addressing the actual problem.

If you’ve been dealing with symptoms that don’t have a clear explanation, or you’ve been told everything looks normal but you still don’t feel well, we’d love to take a closer look. Our team serves patients from Carmel, Westfield, Zionsville, Fishers, Noblesville, and throughout the Indianapolis metro area.

Ready to find out what your nervous system is actually doing? Contact Nexus Neuro today to schedule your evaluation.