Glossary: Heart rate variability (HRV)
Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats and is measured by the variation in the beat-to-beat interval (commonly stated as R-R interval). It is well known that HRV is directly related to the body's interdependent regulatory systems and can be a powerful measure for an athlete's recovery status.
Metrics for HRV
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RMSSD
Root mean square of successive differences. This value is said to be a strong indicator for parasympathetic activity and thus large values indicate a better recovery status. -
lnRMSSD
Natural logarithm of RMSSD. The logarithm is used to achieve a better scaling. -
SDNN
Standard deviation of R-R intervals -
5 min-SDANN
Standard deviation of the average R-R intervals calculated over 5 minutes -
pNN50
Proportion of successive R-R intervals that differ by more than 50 ms -
pNN20
Proportion of successive R-R intervals that differ by more than 20 ms
References
- Heart Rate Variability Explained, hrvtraining.com
- Heart Rate Variability For Training, marcoaltini.com