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Analysis of neural mechanisms accompanying different intensities of dynamic exercise.

Abstract：

:The neural mechanisms accompanying dynamic exercise of different intensities were analyzed in dogs and human subjects by means of autoregressive spectral analysis of heart period and arterial pressure variabilities. In the animal experiments, 8 conscious dogs were examined after implanting a solid state pressure gauge in the left ventricle. Animals were examined at rest and during a treadmill run, at 4 km/h, and 0 degrees incline. The experiments were repeated after chronic alpha 1-adrenoreceptor blockade. During the treadmill run, heart rate and systolic left ventricular pressure increased significantly. Simultaneously, the low frequency (LF, 0.1 Hz) component of pulse interval and of systolic pressure variabilities, ie, markers, respectively, of sympathetic modulation of the SA node and of vasomotor activity, increased significantly (evaluated respectively, in normalized and absolute units). After chronic alpha 1-adrenoreceptor blockade, the increase in LF component of systolic pressure variability was prevented, while that observed in R-R interval variability was maintained. Human studies were carried out with either invasive or noninvasive techniques. In the former approach already described, performed in young hypertensive subjects, arterial pressure was recorded with a high fidelity technique. In the second approach applied to young champion swimmers, only the variability of the R-R interval was examined. In both studies, moderate levels of exercise were accompanied by an increase in the LF component of the spectrum: in the case of arterial pressure variability, this increase was detectable both in absolute and normalized units; vice versa, in the case of R-R variability, since physical exercise is accompanied by a marked abatement of the variance, normalized units had to be used in order to evaluate the shift of the sympathovagal balance in favor of sympathetic overactivity.

journal_name

Chest

journal_title

Chest

authors

Rimoldi O,Furlan R,Pagani MR,Piazza S,Guazzi M,Pagani M,Malliani A

doi

10.1378/chest.101.5_supplement.226s

subject

Has Abstract

pub_date

1992-05-01 00:00:00

pages

226S-230S

issue

5 Suppl

eissn

0012-3692

issn

1931-3543

pii

S0012-3692(16)32906-3

journal_volume

101

pub_type

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Analysis of neural mechanisms accompanying different intensities of dynamic exercise.