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Peripheral chemoreflex sensitivity and sympathetic nerve activity are normal in breath hold divers during training season
Author(s) -
Breskovic Toni,
Ivancev Vladimir,
Banic Ivana,
Jordan Jens,
Dujic Zeljko
Publication year - 2010
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.24.1_supplement.990.15
Subject(s) - heart rate , medicine , blood pressure , anesthesia , vasomotor , ventilation (architecture) , sympathetic nervous system , hypoxia (environmental) , respiratory minute volume , apnea , sympathetic activity , cardiology , respiratory system , oxygen , chemistry , engineering , mechanical engineering , organic chemistry
Breath hold divers are exposed to repeated massive arterial oxygen desaturation, which could perturb chemoreflexes. Therefore, we tested the hypothesis that peripheral chemoreflex regulation of ventilation and sympathetic vasomotor tone is present during the training season. We determined ventilation, heart rate, blood pressure, cardiac stroke volume, and muscle sympathetic nerve activity (MSNA) during isocapnic hypoxia in 10 breath hold divers and 11 matched control subjects at the end of the season of intense apnea trainings. Baseline MSNA frequency was 30±4 bursts/min in control subjects and 25±4 bursts/min in breath hold divers (P=0.053). During hypoxia burst frequency and total sympathetic activity increased similarly in both groups. Sympathetic activity normalized during 30 minute recovery period. Hypoxia‐induced stimulation of minute ventilation was similar in both groups. Hypoxia increased heart rate and cardiac output whereas total peripheral resistance decreased. Blood pressure remained unchanged. We conclude that peripheral chemoreflex regulation of ventilation and sympathetic vasomotor tone is paradoxically preserved in apnea divers during the training season. This study was supported by the Croatian Ministry of Science, Education and Sports.