New indices for quantification of the power spectrum of heart rate variability time series without the need of any frequency band definition

1. The heart and the oesophagus have similar sensory pathways, and sensations originating from the oesophagus are often difficult to differentiate from those of cardiac origin. We hypothesized that oesophageal sensory stimuli could alter neurocardiac function through autonomic reflexes elicited by these oesophageal stimuli. In the present study, we examined the neurocardiac response to oesophageal stimulation and the effects of electrical and mechanical oesophageal stimulation on the power spectrum of beat-to-beat heart rate variability in male volunteers. 2. In 14 healthy volunteers, beat-to-beat heart rate variability was compared at rest and during oesophageal stimulation, using either electrical (200 μs, 16 mA, 0.2 Hz) or mechanical (0.5 s, 14 ml, 0.2 Hz) stimuli. The power spectrum of beat-to-beat heart rate variability was obtained and its low- and high-frequency components were determined. 3. Distal oesophageal stimulation decreased heart rate slightly (both electrical and mechanical) (P < 0.005), and markedly altered heart rate variability (P < 0.001). Both electrical and mechanical oesophageal stimulation increased the absolute and normalized area of the high-frequency band within the power spectrum (P < 0.001), while simultaneously decreasing the low-frequency power (P < 0.005). 4. In humans, oesophageal stimulation, whether electrical or mechanical, appears to amplify respiratory-driven cardiac vagoafferent modulation while decreasing sympathetic modulation. The technique provides access to vagoafferent fibres and thus may yield useful information on the autonomic effects of visceral or oesophageal sensory stimulation.

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Evaluation of the Human Thermal Comfort under Simulated Weightlessness: an Experimental Study Based on the Power Spectrum Analysis of the Heart Rate Variability

Microgravity Science and Technology ◽

10.1007/s12217-018-9669-7 ◽

2018 ◽

Vol 31 (1) ◽

pp. 73-83 ◽

Cited By ~ 2

Author(s):

Hui Zhu ◽

Hanqing Wang ◽

Duanru Li ◽

Zijian Xiao ◽

Hua Su ◽

...

Keyword(s):

Heart Rate ◽

Experimental Study ◽

Heart Rate Variability ◽

Power Spectrum ◽

Thermal Comfort ◽

Spectrum Analysis ◽

Power Spectrum Analysis ◽

Simulated Weightlessness ◽

Human Thermal Comfort

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Body position affects the power spectrum of heart rate variability during dynamic exercise

European Journal of Applied Physiology and Occupational Physiology ◽

10.1007/bf00235095 ◽

1993 ◽

Vol 66 (3) ◽

pp. 207-213 ◽

Cited By ~ 14

Author(s):

Renza Perini ◽

Claudio Orizio ◽

Stefania Milesi ◽

Luca Biancardi ◽

Giuseppe Baselli ◽

...

Keyword(s):

Heart Rate ◽

Heart Rate Variability ◽

Power Spectrum ◽

Body Position ◽

Dynamic Exercise

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On the fractal nature of heart rate variability in humans: effects of respiratory sinus arrhythmia

AJP Heart and Circulatory Physiology ◽

10.1152/ajpheart.1995.269.2.h480 ◽

1995 ◽

Vol 269 (2) ◽

pp. H480-H486 ◽

Cited By ~ 10

Author(s):

Y. Yamamoto ◽

J. O. Fortrat ◽

R. L. Hughson

Keyword(s):

Heart Rate ◽

Time Series ◽

Heart Rate Variability ◽

Coarse Graining ◽

Resting Heart Rate ◽

Breathing Frequency ◽

Fractal Nature ◽

Sinus Arrhythmia ◽

Spectral Exponent ◽

Random Fractal

The purpose of the present study was to investigate the basic fractal nature of the variability in resting heart rate (HRV), relative to that in breathing frequency (BFV) and tidal volume (TVV), and to test the hypothesis that fractal HRV is due to the fractal BFV and/or TVV in humans. In addition, the possible fractal nature of respiratory volume curves (RVC) and HRV was observed. In the first study, eight subjects were tested while they sat quietly in a comfortable chair for 60 min. Beat-to-beat R-R intervals, i.e., HRV, and breath-by-breath BFV and TVV were measured. In the second study, six subjects were tested while they were in the supine position for 20-30 min. The RVC was monitored continuously together with HRV. Coarse-graining spectral analysis (Yamamoto, Y., and R. L. Hughson, Physica D 68: 250-264, 1993) was applied to these signals to evaluate the percentage of random fractal components in the time series (%Fractal) and the spectral exponent (beta), which characterizes irregularity of the signals. The estimates of beta were determined for each variable only over the range normally used to evaluate HRV. Values for %Fractal and beta of both BFV and TVV were significantly (P < 0.05) greater than those for HRV. In addition, there was no significant (P > 0.05) correlation between the beta values of HRV relative to either BFV (r = 0.14) or TVV (r = 0.34). RVC showed a smooth oscillation as compared with HRV; %Fractal for RVC (42.3 +/- 21.7%, mean +/- SD) was significantly (P < 0.05) lower than that for HRV (78.5 +/- 4.2%).(ABSTRACT TRUNCATED AT 250 WORDS)

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