Short-term heart rate variability in healthy adults.

Introduction: Standardised heart rate variability (HRV) analysis is used as a diagnostic and prognostic tool for cardiovascular as well as perioperative risk stratification. The lack of reference values for young and middle-aged subjects however limits implementation of HRV analysis in the clinical setting. With this study we aimed to define reference values, and to define the influences of gender and age for short-term heart rate variability in the young and middle-aged population. Methods: Ninety-three healthy subjects (18-50 years) were studied during standard test conditions. Short-term HRV was assessed using an ECG monitor. Data represent mean ±SD or median with 10th and 90th centiles. To determine gender and age differences Student’s t-test or Mann-Whitney U-test were used. Pearson and Spearman’s rank correlation coefficients were used to determine correlations between age and HRV parameters Results: All parameters for heart rate variability, except for the LF/ (LF+HF), showed significantly higher values for men then for woman (mean normal-to-normal (1014 ±183 vs 896 ±121 ms), standard deviation of normal-to-normal (65.3 (36.6-97.6) vs 49.4 (29.9-91.3) ms), root mean square of successive differences between normal-to-normal (55.8 (24.2-98.7) vs 41.5 (21.5-87.0) ms), very low frequency (1282 (438-4390) vs 785 (259-2090) ms2), low frequency (1025 (361-2983) vs 487 (206-1365) ms2), high frequency (1311 (405-3491) vs 763 (203-3981) ms2) and total spectral power, respectively). Age showed no influence on the baseline characteristics and HRV parameters and showed no significant correlations in a range between -0.21 and 0.27. Conclusions: This study provided reference values for short-term heart rate variability in healthy adults, which may support further implementation of this tool in patient risk stratification.