A Dampening Effect of Pulse Interval Variability on Blood
Pressure Variations with Respect to Primary Variability in Blood
Pressure during Exercise
N. HONZÍKOVÁ, A. KRTIČKA1,
Z. NOVÁKOVÁ, E. ZÁVODNÁ
Department of Physiology, Faculty of Medicine, Masaryk
University, and 1Military Academy, Brno, Czech Republic
Received May
6, 2002
Accepted June 26, 2002
Summary
The correlation between baroreflex sensitivity (BRS) and the
spectrum component at a frequency of 0.1 Hz of pulse intervals
(PI) and systolic blood pressure (SBP) was studied. SBP and PI
of 51 subjects were recorded beat-to-beat at rest (3 min),
during exercise (0.5 W/kg of body weight, 9 min), and at rest (6
min) after exercise. BRS was determined by a spectral method (a
modified alpha index technique). The subjects were divided into
groups according to the spectral amplitude of SBP at a frequency
of 0.1 Hz. The following limits of amplitude (in mm Hg) were
used: very high ≥ 5.4 (VH); high 5.4 > H ≥ 3 (H); medium 3 > M ≥
2 (M), low < 2 (L). We analyzed the relationships between 0.1 Hz
variability in PI and BRS at rest, during the exercise and
during recovery in subgroups VH, H, M, L. The 0.1 Hz variability
of PI increased significantly with increasing BRS in each of the
groups with identical 0.1 Hz variability in SBP. This
relationship was shifted to the lower values of PI variability
at the same BRS with a decrease in SBP variability. The primary
SBP variability increased during exercise. The interrelationship
between the variability of SBP, PI and BRS was identical at rest
and during exercise. A causal interrelationship between the 0.1
Hz variability of SBP and PI, and BRS was shown. During
exercise, the increasing primary variability in SBP due to
sympathetic activation was present, but it did not change the
relationship between variability in pulse intervals and BRS.
Key
words
Baroreflex sensitivity • Spectral analysis • Heart rate
variability • Blood pressure variability • Exercise
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Prof. Dr. Nataša Honzíková, Department of Physiology, Faculty of
Medicine, Komenského nám. 2, 662 43 Brno, Czech Republic. Fax:
+420-5-42126 561, E-mail:
nhonziko@med.muni.cz
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