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Sympathoinhibition in men during paced breathing at 0.25 Hz
Author(s) -
Coverdale Nicole,
Usselman Charlotte W.,
Gimon Tamara I.,
Nielsen Chantelle A.,
Luchyshyn Torri A.,
Shoemaker J. Kevin
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1118.14
Subject(s) - heart rate , supine position , blood pressure , medicine , stroke volume , anesthesia , breathing , respiratory rate , hemodynamics , cardiology
This study tested the hypothesis that paced breathing (PB) would inhibit muscle sympathetic nerve activity (MSNA). Integrated MSNA (peroneal nerve) and hemodynamics were assessed in healthy young men (26 ± 2 years; n=8) while supine during spontaneous breathing over 2 to 5 minutes and then at 0.25 Hz for 4 minutes with a recovery period. Breathing rate was not different between spontaneous and PB (15.6 ± 2.0 vs 15.0 ± 0.5 breaths/minute). Compared to baseline, PB reduced (~25%) burst frequency (19 ± 7 vs 14 ± 8 bursts/minute, p<0.01) and incidence (35 ± 12 vs 27 ± 13 bursts/100 heart beats, p<0.01). These returned to baseline levels during recovery. Total MSNA, (mean burst amplitude x burst frequency) also was reduced with PB (2.5 ± 1.3 a.u.) compared with spontaneous breathing (3.3 ± 1.1 a.u.)(p<0.05). No differences were observed in heart rate, mean arterial pressure, burst amplitude, or stroke volume between conditions but cardiac output was higher (~10%) during PB (3.6 ± 0.9 L/min) versus baseline (4.0 ± 0.9 L/min)(p<0.05). Therefore, PB inhibited MSNA in a manner that was not accounted for by concurrent changes in blood pressure or cardiac output. Supported by CIHR and NSERC.