Relationships between pulse wave velocity and heart rate variability in healthy men with a range of moderate-to-vigorous physical activity levels.

Pulse wave velocity (PWV) is associated with heart rate variability (HRV) in 24-39-year-old men. This study of 40-65-year-old men ranging in moderate-to-vigorous physical activity levels investigated whether (a) PWV is related to spectral HRV, (b) using normalised units for HRV influences that relationship, and (c) HRV predicts PWV when other factors, including age and blood pressure, are accounted for. Subjects were healthy men (N=115), mean (SD) age 50.8 (7.1) years. Carotid-femoral PWV was measured using Complior. HRV was derived from a 5 min ECG for total, high-frequency, and low-frequency power (TP, HF, and LF, respectively), the LF/HF ratio, and normalised units for HF (HFnu) and LF (LFnu). Non-parametric data were natural log-transformed. PWV was 8.5 (1.4) m s-1. TP, HF, LF, LF/HF, HFnu and LFnu were 1908 (2195) m s2, 577 (1034) m s2, 457 (514) m s2, 1.5 (1.3), 46.8 (17.9), and 49.4 (19.4), respectively. PWV was inversely associated with TP (R2=0.061, p=0.008), HF (R2=0.095, p=0.001), LF (R2=0.086, p=0.002) and HFnu (R2=0.040, p=0.031), but was not associated with LF/HF (R2=0.020, p=0.136) or LFnu (R2=0.028 p=0.076). Only age and systolic blood pressure (adjusted R2=0.306, p<0.001) predicted PWV in multivariate analysis. This study has shown that PWV was weakly associated with TP and HF. The use of normalised units only influenced the relationship between PWV and LF. Finally, relationships between PWV and HRV are mediated through age and systolic blood pressure in this population of men ranging in moderate-to-vigorous physical activity level.