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
