FAQ – Frequently asked questions & answers
On the following frequently asked questions you will find our comments and notes. Questions that are not covered here, you are welcome to send us via contact form, we will respond as soon as possible.
What does HRV mean?
HRV means Heart Rate Variability, also known as heart frequency variability or heart rhythm variability.
What is measured in HRV analysis?
HRV measurement, also called HRV analysis, measures the time intervals from heartbeat to heartbeat (RR intervals) in milliseconds. An ECG records so-called QRS signals, and in a resting measurement the intervals should vary constantly and be different.
What is the validity of HRV analysis as a short-term measurement?
The short-term measurement is just as meaningful as a long-term measurement. The data are validated and correlate with those from the long-term measurement. This has been confirmed in many HRV comparison studies. Since August 2011, short-term measurement has been part of the national care guidelines in the field of diabetes in Germany.
A major difference is that short-term measurement (4-10 minutes) is much easier, faster and more practical than long-term measurement. It should also be noted that in the case of long-term measurement (e.g. 24 hours), the person concerned must keep very precise records of what he or she has done and thought at what time. A time-consuming error correction may also have to be carried out. The evaluation thus takes much longer overall, despite software support, and does not provide any additional information compared to a short-term measurement.
Which HRV parameters are important and relevant?
From our point of view it is the following information and values: rhythmogram, scatter diagram, histogram, stress index (SI), rest/relaxation index (RI), heart rate. Often the value SDNN (standard deviation) is also used, whereby this is very closely related to the RI.
With even more information and graphics, no more knowledge is gained – on the contrary, most users get confused and do not understand what is displayed, or what meaning these graphics or values have. All essential information is contained in the above parameters and graphics.
What is the main message of HRV analysis?
It is determined whether in a rest situation the relaxation nerve (parasympathetic nervous system) is dominant or whether the body is still in stress / permanent stress mode, which is biologically interpreted as a “fight and flight” situation and regulated accordingly.
What information can be used to monitor therapy?
If a stress or permanent stress has been identified, the goal of any therapy, medication (holistic-biological approach) or change in life / consciousness should be to increase the RI value (parasympathetic activity) and reduce the SI (sympathetic activity). Only when the parasympathetic / vagus is dominant can profound regeneration and repair processes take place effectively! The effects of any therapies on the autonomic nervous system (ANS), whether classical orthodox or biological naturopathic therapies, can be quickly visualized.
Can the effect of medication on the VNS be tested?
Yes, e.g. the effects (and possible overdose) of BETA blockers, COPD drugs, vaccinations, chemotherapy, homeopathy or psychotropic drugs can be quickly and easily visualized with HRV analysis.
Can diagnoses be made with HRV analysis?
No. Only the current regulatory capacity of the autonomic nervous system as a higher-level control center can be measured and how the two main nerves, sympathetic and parasympathetic, relate to each other.
Are the HRV measurements reproducible?
Yes, as far as this is possible with biologically open systems. The basic regulation does not change that much during the course of the day, so that you can, for example, see just as “good” a measurement in the morning as in the evening. Slight fluctuations are completely normal, since you regulate as an open biological system, i.e. you adapt to the constantly changing conditions of your environment and your own thought processes.
How is regulation defined?
Definition: Regulation is the constant and situational adjustment of all bodily functions by the autonomic nervous system (ANS).
Second by second our body has to adjust to different stimuli from our environment and the inside of our body and react accordingly in a meaningful way – be it eating, running, sprinting, discussing, sleeping, writing and so on. Every minute of the day and night, the ANS adapts to the different conditions and thus a constant adjustment / regulation of the most diverse systems takes place.
What should be considered for the regular measurement?
In order to be able to compare well, the measurements should always be taken at rest under identical conditions, sitting or lying down. During the measurement it is good not to move, not to talk and to relax as much as possible.
A breathing technique with a preset rhythm should not be used, so that no “external” rhythm is preset. The measurement results would no longer be original, but “manipulated”.
How long does an HRV measurement take?
The HRV measurement records either 260 or 520 RR intervals. The measurement duration therefore varies depending on the pulse of the person being measured. With a pulse of 100, the measurement takes just under 5 minutes (with 520 RR intervals), with a pulse of 50 it takes just under 10 minutes (with 520 RR intervals). On average, it takes 8 minutes. The short measurement with 260 RR intervals is correspondingly half as long.
How accurately does HRV analysis measure?
The measurement resolution is 1 millisecond (ms). Via a chest strap, the RR distances in milliseconds are sent directly to the smartphone / tablet via Bluetooth.
How far apart may the receiver and chest strap be?
The range is about 5 meters. The transmission and reception quality between chest strap and receiver is displayed in percent, as well as the battery charge in percent of the chest strap. If several chest straps are received and send data during a new measurement, the correct chest strap can be selected.
How often should an HRV analysis be performed?
This depends on the question and user group. Users with chronic complaints should carry out an HRV measurement at least once a week in order to be able to check/monitor the effectiveness of therapeutic measures and/or medication, for example. In order to observe oneself and to get to know one’s own regulation processes better, it makes sense to carry out the measurement more frequently at the beginning.
Ambitious athletes and professional athletes can perform a daily HRV measurement after getting up during intensive training phases in order to better control their training intensity and regeneration status (e.g. in training camps), which results in a higher performance output.
How do I interpret HRV readings with "very low RI / parasympathetic value" when there are no symptoms or complaints?
Very low RI values usually mean high SI values at the same time.
Stress/continuous stress or active biological conflicts are often present here. Whether relationship stress, family stress, quarrels with the children, the boss or employees, financial difficulties or unemployment – all this causes high to very high SI values (stress index) in the long run. Here it is important to find out the exact causes that cause the stress and, if possible, to reduce or eliminate them. Because long before organically manifested symptoms or “illnesses” occur, the measured values SI index and RI index provide initial indications.
Who cannot or should not perform HRV measurements?
People with a continuously regulating pacemaker do not need to perform HRV measurements because the evaluations have no meaning or significance. An external beat is given and thus no conclusions can be made about the body’s own regulation of the ANS.
Bei absoluten Herz-Arrhythmien (Vorhofflimmern) können die Hauptparameter nur eingeschränkt genutzt werden, weil die mathematischen Berechnungen eine „sehr gute“ Variabilität ergeben.
Im Rhythmogramm lassen sich über einen längeren Zeitraum die Auswirkungen von Medikamenten oder Therapien überprüfen. Hierbei wird nur das Gesamtbild des Rhythmogramms beachtet, ob die „Ausreißer“ nach oben und unten (Peaks) weniger werden. Vereinfacht gesagt: weniger Ausreißer = weniger Arrhythmien = gute Therapie.