Chemosensitivity and Regulation of Ventilation during Sleep at High Altitudes

Abstract

The paper presents new observations on young high altitude natives (Andes and Himalayas), testing the hypothesis that periodic breathing with apnea during sleep is determined by their ventilatory sensitivity to hypoxia and its interaction with the sleep state. The hypothesis is in general supported by the evidence. But, contrary to expectation, the ventilatory sensitivity to hypoxia in the Sherpa children was significantly lower than those in the Andes. Despite that departure, the magnitude of ventilatory periodicity among the subjects was internally consistent with their ventilatory sensitivity to hypoxia. Although the carotid chemosensory input is the pacesetter for the reflexive periodicity, mechanisms in the central nervous system can influence it significantly.

Key words

Apnea - carbon dioxide - hydrogen ion - oxygen - periodic breathing - peripheral chemoreceptors - sleep state - threshold-stimulus