Sex differences in cardiac responses to successive apnea periods.
Cardiac response to breath-holding is generally described as a bradycardia, which is explained by a two-fold mechanism involving the pulmonary mechanoreceptors and the arterial chemoreceptors. This study was conducted to determine the cardiac effects of five successive apnea periods separated by 1 min of free ventilation (FV). Heart rate (HR) and ventilation (V, VT, f) were measured during this protocol in 12 young subjects (6 men, 6 women). Ventilatory responses during FV periods were similar in both sexes, but HR responses were different during the apnea periods. The mean exhibited a bradycardia and the women a tachycardia. Although the statistical significance of the results was weak, they showed a clear tendency which was interpreted as differences in central cardioventilatory interactions. Sex difference in the cardiac consequences of static work from respiratory muscle is also evoked.
D000328:Adult; D001049:Apnea / Q000503:physiopathology*; D001919:Bradycardia / Q000503:physiopathology; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D012119:Respiration; D012737:Sex Factors; D013610:Tachycardia / Q000503:physiopathology; D013997:Time Factors