Heart rate variability from Holter monitoring in a normal population

The determination of the normal heart rate variability (HRV) range in the time and frequency domain with a commercially available Holter monitoring system in a group of carefully selected normal subjects is addressed. Spectral analysis of HRV using the fast Fourier transformation technique revealed total-, low-, and high-frequency standard variation. Time-domain HRV parameters were also calculated from the same recording. The total-, low-, and high-frequency standard deviation as well as the pNN50 were found to be lower in subjects over 45 yrs than in those under (p=0.04-0.07). Furthermore, gender-related differences in HRV were also observed: the total- and low-frequency standard deviation as well as the standard deviation of all normal coupling intervals were lower in women than in men (p=0.002-0.06). The authors conclude that HRV in normals is age- and gender-related