Heart rate

Variability [hrv]



Heart Rate Variability:
Heart rate variability (HRV) is an evidence based health indicator, which can give a general assessment of a patient’s physiological state and has a wide range of clinical applications, in terms of giving the clinician feedback on the possible effectiveness of treatments/therapies utilized. HRV is the beat-to-beat variation in the heart rate (RR interval seen on EKG) that is regulated by both branches of the autonomic nervous system (ANS), which are the sympathetic nervous system (SNS) and parasympathetic nervous system (PSNS)(1,2). Parasympathetic modulation of the heart rate is fast (timescale in the order of milliseconds), which correlates with high frequency (HF) [0.15 -0.5 Hz] variation in the HRV analysis, while sympathetic effects are much slower and correlate more with low frequency (LF) [0.033 – 0.15 Hz] variation (1,2,3). However, the power of the LF band does have a mixture of various regulatory inputs on top of the sympathetic dominance, which includes a partial PSNS input, as well as on the activity of the baroreceptors, thermoregulation, and some neurohumoral mechanisms [1].

In simple terms, the SNS is the branch of the ANS associated with fight or flight (the stress response), while the PSNS branch focuses on rest, digest, and healing (energy conservation, recuperation, and restorative processes). The importance of proper regulation of the ANS lies in the fact that it controls approximately 90% of the body’s functions. These “automatic” functions of the ANS include, heart rate, breathing, blood pressure, temperature regulation, sweating, and many more.


  1. Riftine, Alexander. Quantitative Assessment of the Autonomic Nervous System based on Heart Rate Variability Analysis: Theoretical Review and Clinical Us. 2002.

  2. Koenig J, Williams DP, Kemp AH, Thayer JF. Vagally mediated heart rate variability in headache patients--a systematic review and meta-analysis. Cephalalgia. 2016 Mar;36(3):265-78. doi: 10.1177/0333102415583989. Review. PubMed PMID: 25962595.

  3. Levy MN. Neural control of cardiac function. Baillieres Clin Neurol 1997; 6: 227–244.




The Varicard HRV uses a specialized Integrated system for cardiointervalometry analysis.

The complex "Varicard" is intended for HRV analysis in various areas of applied physiology, preventive medicine and clinical practice. It provides a realization of all the basic methods of  HRV analysis (statistical analysis, variational pulsometry, correlation rhythmography, autocorrelation and spectral analysis) and allows us to calculate up to 40 various parameters! 

Simply put this advanced device that has been used with astronauts in the past will allow for a baseline of the patients ANS to be obtained, and will give other insights such as on cardiovascular health, neuroendocrine system, etc. At the same time it can allow tracking of progress with different interventions and therapies used during a patients healing journey at EHS! 

The test only takes 5 minutes, where clips are fastened to a patient's wrist and ankles as they sit naturally in a chair. 

If doing this test in Clinic, we ask patients to abstain from having any caffeine or other stimulants that day and ideally they will have not eaten for at least 1 hour before the test. However, drinking plenty of water is encouraged!


The major contraindications for this test would be for those that have pacemakers...but if you have any questions about it, feel free to ask us!