![cover image](https://wikiwandv2-19431.kxcdn.com/_next/image?url=https://upload.wikimedia.org/wikipedia/commons/thumb/f/fd/Heart_rate_variability_ECG.jpg/640px-Heart_rate_variability_ECG.jpg&w=640&q=50)
Heart rate variability
Variation in the time intervals between heartbeats / From Wikipedia, the free encyclopedia
Dear Wikiwand AI, let's keep it short by simply answering these key questions:
Can you list the top facts and stats about Heart rate variability?
Summarize this article for a 10 year old
Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats. It is measured by the variation in the beat-to-beat interval.
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/b/be/Heart_rate_variability_%28HRV%29.svg/320px-Heart_rate_variability_%28HRV%29.svg.png)
![Thumb image](http://upload.wikimedia.org/wikipedia/commons/thumb/f/fd/Heart_rate_variability_ECG.jpg/640px-Heart_rate_variability_ECG.jpg)
Other terms used include "cycle length variability", "R–R variability" (where R is a point corresponding to the peak of the QRS complex of the ECG wave; and R–R is the interval between successive Rs), and "heart period variability".[1] Measurement of the RR interval is used to derive heart rate variability.[1]
Methods used to detect beats include ECG, blood pressure, ballistocardiograms,[2][3] and the pulse wave signal derived from a photoplethysmograph (PPG). ECG is considered the gold standard for HRV measurement[4] because it provides a direct reflection of cardiac electric activity.[5]