We compared parameters for heart rate variability (HRV), and selfdependence for their sensitivity to orthostatic change, and whether this sensitivity depended on sympathetic (S) or parasympathetic (PS) changes within the autonomic balance. Seven healthy males were brought to 12, 30, 53, and 70° of head-up position for 30 min to change their S-PS activities in a quantitative fashion. Data were filtered for the low (0.05-0.15 Hz, LF) and high (0.15-0,35 Hz, LF) frequency band to separate S and PS activities. To assess HRV approximate entropy, fractal dimension, root mean square successive difference, and difference points density were computed. For selfdependence autocorrelation coefficients (AC), and frequency of runs were calculated. Whereas selfdependence parameters were found to be effective for LF, HRV parameters were effective for HF. AC were the most sensitive parameters over all comparisons. This could be explained by autocorrelation function patterns for unfiltered and filtered data. We conclude that AC at the first two lags are able to estimate changes of autonomic balance, and describe heart rate fluctuations in a more sensitive way than common HRV parameters.
|Publication status||Published - Dec 1 1997|
ASJC Scopus subject areas
- Molecular Biology