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Exercise‐induced muscle chemoreflex modulation of spontaneous baroreflex sensitivity in man
Author(s) -
Carrington C. A.,
White M. J.
Publication year - 2001
Publication title -
the journal of physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.802
H-Index - 240
eISSN - 1469-7793
pISSN - 0022-3751
DOI - 10.1111/j.1469-7793.2001.00957.x
Subject(s) - baroreflex , isometric exercise , medicine , blood pressure , cardiology , anesthesia , heart rate
1 The goal of this study was to determine the effect of exercise‐induced muscle chemoreflex activation on baroreflex sensitivity (BRS). This is a retrospective study using data obtained during two prior studies. 2 Twenty‐three subjects with a mean ( s.e.m. ) age of 28 (1.5) years took part in the study. Sequence analysis was performed on the systolic blood pressure (SBP) responses, measured by a Finapres, and R‐R intervals, measured from the ECG. 3 Electrically evoked isometric exercise (Stim) of the triceps surae was performed for 2 min at 30 % maximum voluntary contraction force. During exercise and for a further 2 min thereafter, circulation to the lower leg was occluded by inflation of a thigh cuff to above 200 mmHg. 4 Prior to exercise mean (± s.e.m. ) BRS was 10.92 ± 6.3 ms mmHg −1 , and BRS remained at this level during evoked exercise (10.90 ± 7.1 ms mmHg −1 ). BRS increased to 12.34 ± 6.0 ms mmHg −1 during post‐exercise circulatory occlusion (PECO) ( P < 0.05 , MANOVA, post hoc Student's paired t test vs . Stim) and fell to 9.27 ± 4.4 ms mmHg −1 during recovery ( P < 0.01 vs . PECO value, P = 0.059 vs . resting value). 5 These data indicate that during PECO following electrically evoked plantar flexion, where only muscle chemosensitive afferents were likely to be stimulated, BRS was increased.