Abstract
Katayama, Keisho, Hiroshi Fujita, Kohei Sato, Koji Ishida, Ken-Ichi Iwasaki, and Miharu Miyamura.
Effect of a repeated series of intermittent hypoxic exposures on ventilatory response in
humans. High Alt. Med. Biol. 6:50–59, 2005—.The purpose of this study was to elucidate the magnitude
and the time course of ventilatory changes resulting from a repeated series of hypoxic
exposures. Eight healthy males participated in the present study. The subjects spent 1 h/day in
normobaric hypoxia (12% inspired oxygen). Inspired minute ventilation (
), end-tidal partial
pressure of carbon dioxide (PETCO2
), and arterial oxygen saturation (SaO2
) were measured in a
hypoxic tent. These measurements were taken for 10 consecutive days (series 1), and were taken
again after the subjects had been away from hypoxic exposure for 1 month (series 2). PETCO2
decreased
and SaO2
increased progressively in the hypoxic tent during the 10 days of intermittent
hypoxia in series 1. At the onset of series 2 (days 1 to 3), PETCO2
was significantly lower and SaO2
was significantly higher than those on day 1 during series 1. These results suggest that humans
who have had previous hypoxic exposure adapt sooner to hypoxic condition due to an increase
in the magnitude of hyperventilation in the first few days of a series of reexposures to hypoxia.
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