Effects of aging on 24-h dynamic baroreceptor control of heart rate in ambulant subjects

G. Parati, A. Frattola, M. Di Rienzo, P. Castiglioni, A. Pedotti, G. Mancia

Research output: Contribution to journalArticlepeer-review

Abstract

The effects of aging on the dynamic modulation of baroreflex sensitivity over 24 h was assessed in eight elderly (mean age ± SD, 63.9 ± 3.2 yr) and in eight young (23.9 ± 6.1 yr) mild or moderate essential hypertensive patients, who were subject to a 24-h intra-arterial (Oxford technique) blood pressure recording in ambulatory conditions. The sensitivity of baroreflex control of the heart rate was dynamically assessed by quantifying 1) the slope of the regression line between pulse interval (the reciprocal of heart rate) and systolic blood pressure changes over spontaneously occurring hypertension-bradycardia or hypotension-tachycardia sequences (time domain analysis) and 2) the ratio between spectral powers of pulse interval and systolic blood pressure around 0.1 Hz (α-coefficient: frequency domain analysis). The 24-h average sequence slope was lower in old than in young individuals (4.4 ± 0.5 vs. 9.9 ± 1.3 and 4.8 ± 0.7 vs. 8.4 ± 1.4 ms/mmHg for hypertension-bradycardia and hypotension-tachycardia sequences, respectively; P <0.05 for both). Similar results were obtained by using the α-coefficient approach. The marked nighttime increase in baroreflex sensitivity observed in young individuals was much less evident in the elderly. Thus 24-h baroreflex sensitivity is markedly impaired by aging. The impairment becomes manifest also as an inability to increase baroreflex sensitivity at night.

Original languageEnglish
JournalAmerican Journal of Physiology - Heart and Circulatory Physiology
Volume268
Issue number4 37-4
Publication statusPublished - 1995

Keywords

  • ambulatory blood pressure monitoring
  • baroreflexes
  • blood pressure variability
  • sequence analysis
  • spectral analysis
  • variability

ASJC Scopus subject areas

  • Physiology
  • Agricultural and Biological Sciences(all)

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