The Premier Integrative Applied Neurology
and Therapeutic Laser Center of Arizona

Heart Rate Variability (HRV)

“HRV is an interesting and noninvasive way to identify these ANS imbalances. If a person’s system is in more of a fight-or-flight mode, the variation between subsequent heartbeats is low. If one is in a more relaxed state, the variation between beats is high. In other words, the healthier the ANS the faster you are able to switch gears, showing more resilience and flexibility. Over the past few decades, research has shown a relationship between low HRV and worsening depression or anxiety. A low HRV is even associated with an increased risk of death and cardiovascular disease.”
– Harvard Health Publishing   (

What is Heart Rate Variability, and what does it mean for my health?

Recently we began utilizing an HRV device from Nerve Express. We had been contemplating this as a clinic, and we finally had the opportunity to obtain one that our colleagues felt was accurate, easy to use, and provided lots of pertinent information for us clinically.

In general, HRV is assessing the difference between your sympathetic (SNS) and parasympathetic (PSNS) function. For more in-depth information on SNS vs PSNS systems, please visit any of our previous blog posts.

In the basic sense, the SNS is your “Fight or Flight” system and your PSNS is your “Rest and Digest” system. Typically you want your PSNS system firing most of the time, and you want the ability to fire your SNS system whenever something dangerous happens, something stressful occurs, or you’re being chased by a pack of wild dogs! We want to have the ability to tap shift rapidly back and forth between these systems. It is imperative! If we cannot activate one of them, or if one is OVERACTIVE (which is typically the SNS) then we are in big trouble.

What HRV does, is evaluates these systems at their most stable points, then gives us the ability to evaluate during real-time activity.

The test is administered as follows:

Over the course of approximately 8 minutes you will be evaluated with a holter monitor while lying down, standing up, deep breathing and performing a valsalva (or just holding your breath). 

Lying down is the position that should promote the most relaxation and stability. We should be PSNS dominant in this position, and the SNS should be neutral or calmed down. Once a baseline has been identified by the software, it asks you to stand up. Upon standing, multiple parts of your nervous system are activated and there should still be an overall balance to your system.

Possible abnormalities:

When lying down-

SNS is elevated when lying down = unstable and sympathetic dominant

PSNS is decreased when lying down = weak PSNS and by default sympathetic dominant

Upon Standing-

PSNS drops, means that your nervous system cannot tolerate you standing in gravity, therefore you are unstable, and your nervous system will suffer because your cardiovascular system cannot direct blood flow properly.

Once this test is performed our system will instruct you to sit down, breathe normally for a minute or so, then will ask you to hold your breath (essentially hold it as long as possible, or two long holds). After that you are instructed to perform deep breathing. We instruct a 4-4-8, which is a 4 second inhale, 4 second hold of the breath, 8 second exhale. We utilize this breathing technique as a therapy very often, so we employ this during the testing to see how beneficial it can be for someone.

Once the results are confirmed, we review them immediately with the patient, and we can track progress as we move through therapeutic programs.

Ideally, deep breathing and holding of the breath will activate the PSNS and dampen the SNS. We find that most of our patients seeking care, especially in the chronic illness arena, both orthostatic and breathing components are abnormal.

We can utilize different therapies to stimulate different brain regions that helps to activate the PSNS or dampen the SNS based on Heart Rate Variability evaluations, our physical exams, and other diagnostic studies including VNG/VOG and Computerized Dynamic Posturography (balance testing).

If you’re curious to see the stability of your sympathetic and parasympathetic systems, please contact our office, and we will include this in our initial evaluation at no additional cost.