SVEUČILIŠTE U SPLITU

摘要: Objectives Involuntary apnea episodes in obstructive sleep patients result selective potentiation of peripheral chemoreceptor regulation sympathetic vasomotor tone. Breath-hold diving is associated with repeated ‘‘voluntary’’ and massive arterial oxygen desaturation, which could also perturb chemoreflex function. Methods We measured ventilation, heart rate, blood pressure, cardiac stroke volume, muscle nerve activity (MSNA) during isocapnic hypoxia 11 breath-hold divers eleven matched control subjects. The study was carried out at least 1 month after intense training. Results Baseline MSNA frequency 30 ± 4 bursts/ min subjects 31 7 bursts/min (ns). During total increased similarly both groups (30 66% controls 27 60% divers, respectively). remained termination approached baseline measurements 20 min. Hypoxia-induced stimulation minute ventilation similar groups, although it maintained by higher tidal volumes lower breathing compared In hypoxia-induced tachycardia drove an increase output whereas resistance decreased. Blood pressure unchanged. Interpretation conclude that the end intensive training/competition periods, show normal Although voluntary may not lead to sustained changes nervous system regulation, we cannot exclude possibility activation elicited imposes a burden on cardiovascular system.