Effects of Hemoglobin Concentration on Heart Rate Variability

Context: Previous studies reported decreased heart rate variability (HRV) among subjects with anemia. However, the underlying pathology of anemia may be the direct cause of low HRV which may preclude from drawing the conclusion that anemia per se causes diminished HRV. Aim: To detect the relationship between hemoglobin concentrations and HRV. Setting and Design: It was a cross-sectional case-control laboratorybased study. Patients and Methods: The study involved 25 apparently healthy males and 28 females. The ages of both groups ranged between 20 and 38 years. Colorimetry was used for the estimation of random blood glucose and hemoglobin concentrations. Biocom 3000 ECG recorder was used for studying HRV. Statistical Analysis: Data were analyzed using SPSS for windows (version 18). Mean heart rate was introduced as a covariate when screening studied variables for significant correlation between hemoglobin concentrations and heart rate variability indices using partial correlations. Results: The mean hemoglobin concentration of the males (mean (M) ± standard deviation (SD) = 14.4 ± 1.4) was significantly higher compared with the mean hemoglobin concentration of the females (M ± SD = 11.6 ± 1.6) (P = 0.000). In contrast to time domain HRV indices, total power (TP), very low frequency (VLF), low frequency (LF) and high frequency (HF) correlate positively with hemoglobin concentrations (correlation coefficients (CC) ≥ 0.27, P < 0.05 for all). Conclusion: Low hemoglobin concentrations are associated with lower TP, VLF, LF, and HF bands of power spectral density HRV putting anemic patients at higher cardiac risk.