What is HRV

Heart rate variability (HRV) is a biosignal that reveals the beat-to-beat rhythm of the heart. It can be formed from an electrocardiogram (ECG) recording, see figure 1. Because the contraction rate of the heart is controlled by the autonomic nervous system (ANS), information about the ANS can be derived from HRV recordings.

The term heart rate variability is also often used to describe the many metrics that can be calculated from the HRV time series. The calculation and interpretation of these metrics is called universally HRV analysis. Applications of HRV analysis are found in the fields of e.g. sports science, ergonomics, cardiology, diabetes care and research on the physiology of the autonomic nervous system.

Other measurement methods, such as photoplethysmography, biomedical ultrasound, positron emission tomography, microwave reflectometry and continuous blood pressure measurements can be used to get information about the physiology of the heart. But the measured signals in these methods are only indirectly related to the activation of the sinus node, the pacemaker of the heart, which is a bioelectrical event. This is best revealed by ECG or magnetocardiography (MCG). Because of the size and the nature of magnetocardiography devices, only ECG is suitable for ambulatory recordings from these two methods.

For different applications, there are different HRV measurement systems. For long term measurements, often 24 hours and up to several days, a lightweight and unobtrusive measurement device is an advantage. Disposable and adhesive ECG electrodes, that are widely clinically utilized, provide the best signal quality for artefact free recordings.
HRV Setup
Figure 1: Mobile ECG measurement.
HRV Hear Rate Variability
Figure 2: Above: Intervals between consecutive R waves on top of the measured ECG signal. Below: RR time series, which is formed from the RR intervals. This is also called the HRV time series.

Related products

  1. eMotion HRV
  2. Mega Innovation

Further readings

  1. About HRV measurement instruments on HRV24.de (GER)