Skip to main content

Table 1 Overview of the HRV parameters

From: Assessing physiological response mechanisms and the role of psychosocial job resources in the physical activity health paradox: study protocol for the Flemish Employees’ Physical Activity (FEPA) study

Parameter Unit Description
Time-domain measures
 Mean HR bpm Mean heart rate (reflects physical activity and sympatho-vagal balance)
 Mean RR ms Mean of the selected beat-to-beat RR interval series (inversely proportional to mean HR)
 SDNN ms Standard deviation of the IBI of normal sinus beats (demonstrates overall HRV)
 HRVindex ms Integral of the density of the RR interval histogram divided by its height
 SDANN ms Standard deviation of the averages NN (normal-to-normal) intervals for each of the 5 min segments during a 24 h recording
 RMSSD ms Root mean square of successive RR interval differences (reflects mainly parasympathetic activation of the autonomic nervous system)
 pNN50 % Percentage of successive NN intervals that differ by more than 50 ms (NN50) divided by the total number of all NN intervals
Frequency-domain measures
 HRV ms2 Total energy across all spectral bands of the frequency analysis
 LF power ms2 Absolute power of the low-frequency band (frequency range 0.04–0.15 Hz) (reflects both sympathetic and parasympathetic activation)
 HF power ms2 Absolute power of the high-frequency band (frequency range 0.15–0.4 Hz) (reflects parasympathetic activation)
 LF/HF LF/HF power ratio (estimates sympatho-vagal balance)
Non-linear measures
 SD1 ms Poincaré plot standard deviation perpendicular the line of identity
 SD2 ms Poincaré plot standard deviation along the line of identity
  1. Abbreviations: HR heart rate, bpm beats per minute, RR interbeat, IBI interbeat interval, HRV heart rate variability, NN normal-to-normal, Hz Hertz, LF low frequency, HF high frequency, SD standard deviation