Fractal nature of short-term systolic BP and HR variability during lower body negative pressure

摘要: We have shown previously that the heart rate variability (HRV) signal is fractal in nature with a high degree of complexity, as given by calculated dimension (DF). also reported loss indicated reduction DF HRV, associated orthostatic hypotension and impending syncope. To extend this investigation cardiovascular responses, we investigated characteristics short-term systolic blood pressure (BPV) coincident measurements HRV during stress. Eight healthy men completed test protocol 20 min supine rest followed sequentially 10 at each -5, -15, -25, -40, -50 mmHg lower body negative (LBNP) recovery. found resting BPV were approximately 70% both variables component signal. The slope 1/f beta relationship was 1.16 +/- 0.12 for 2.31 0.17 BPV. With increasing levels stress, increased significantly to 1.68 0.08 LBNP, whereas unchanged Indicators parasympathetic sympathetic nervous system activity derived from suggested reduced values, respectively, LBNP increased. These data indicate important differences control under