TY - JOUR
T1 - Effect of autonomic blockade on power spectrum of heart rate variability during exercise
AU - Warren, John H.
AU - Jaffe, Rory S.
AU - Wraa, Cheryl E.
AU - Stebbins, Charles L
PY - 1997
Y1 - 1997
N2 - To validate power spectral analysis of heart rate variability (HRV) as an autonomic indicator during exercise, ten males performed four identical progressive cycling tests during infusions of saline, esmolol (β1-blocker), glycopyrrolate (muscarinic blocker), or both drugs. Power spectra were constructed from the recorded electrocardiogram by Fourier algorithm and integrated for low-frequency power (LF) and high-frequency power (HF). Four different LF bands (0.004-0.1, 0.004-0.15, 0.05-0.1, and 0.05-0.15 Hz) and two different HF bands (0.1-1.0 and 0.15-1.0 Hz) were evaluated. The parasympathetic index, HF, decreased exponentially with workload and was attenuated by glycopyrrolate and combined treatments with both HF frequency bands measured. Whereas some sympathetic indexes (LF/total power and LF/HF) did reflect expected increases in sympathetic nerve activity associated with progressive increases in work intensity, none of the measured increases responded appropriately to autonomic blockade. It is concluded that HRV is a valid technique for noninvasive measurement of parasympathetic tone during exercise, but its validity as a measure of sympathetic tone during exercise is equivocal.
AB - To validate power spectral analysis of heart rate variability (HRV) as an autonomic indicator during exercise, ten males performed four identical progressive cycling tests during infusions of saline, esmolol (β1-blocker), glycopyrrolate (muscarinic blocker), or both drugs. Power spectra were constructed from the recorded electrocardiogram by Fourier algorithm and integrated for low-frequency power (LF) and high-frequency power (HF). Four different LF bands (0.004-0.1, 0.004-0.15, 0.05-0.1, and 0.05-0.15 Hz) and two different HF bands (0.1-1.0 and 0.15-1.0 Hz) were evaluated. The parasympathetic index, HF, decreased exponentially with workload and was attenuated by glycopyrrolate and combined treatments with both HF frequency bands measured. Whereas some sympathetic indexes (LF/total power and LF/HF) did reflect expected increases in sympathetic nerve activity associated with progressive increases in work intensity, none of the measured increases responded appropriately to autonomic blockade. It is concluded that HRV is a valid technique for noninvasive measurement of parasympathetic tone during exercise, but its validity as a measure of sympathetic tone during exercise is equivocal.
KW - β-adrenergic receptor antagonism
KW - Humans
KW - Muscarinic receptor antagonism
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M3 - Article
C2 - 9277531
AN - SCOPUS:0030870492
VL - 273
JO - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
JF - American Journal of Physiology - Renal Fluid and Electrolyte Physiology
SN - 1931-857X
IS - 2 42-2
ER -