The contribution of peripheral chemoreceptors to ventilation during heavy exercise.
The purpose of this study was to determine, in man, the contribution of peripheral chemoreceptors to ventilation during constant-load, heavy exercise above anaerobic threshold at sea level, using hyperoxic suppression of peripheral chemoreceptor drive which was obtained by abrupt and surreptitious replacement of inspired air with 100% oxygen for a period of 20-30 sec during the exercise. There was a delay of at least 1 sec from the time of peripheral chemoreceptor blockade to the initial change in ventilation, suggesting the operation of a central neural reverberatory mechanism after the cessation of peripheral chemoreceptor drive. In contrast to Wasserman (1976), whose results indicated a 25% decrease in ventilation within two breaths, in the present study no significant drop was observed until some 4-6 breaths after the air-to-oxygen switch. Furthermore, the drop in ventilation, magnitude of which was of the order of 15%, was transient in 5 out of 8 subjects. In one subject, the ventilation increased following oxygen administration. It is concluded that the peripheral chemoreceptors are not the sole mediators of hyperventilation of heavy exercise above anaerobic threshold in man.
D000138:Acidosis / Q000503:physiopathology; D000328:Adult; D000693:Anaerobiosis; D001776:Blood Circulation Time; D002344:Carotid Body / Q000502:physiology; D002628:Chemoreceptor Cells / Q000502:physiology*; D006801:Humans; D008297:Male; D010100:Oxygen / Q000502:physiology; D005082:Physical Exertion; D012119:Respiration
D010100:Oxygen