Abstract
Absence of oxygen to the brain for even a very few minutes results in loss of consciousness
and can cause permanent injury. Can the wanderer to the limits of earth-bound hypoxia
suffer similar harm from more prolonged exposure to milder hypoxia that does not cause
loss of consciousness? I shall review the results from studies where neurobehavioral
function has been compared in mountaineers before and after return from great heights
and in individuals with chronic pulmonary disease before and after prolonged, continuous
oxygen therapy. Many (although not all) of these studies report mild impairment of
neurobehavioral function after fairly prolonged hypoxic exposure. Impairment was manifest
by deficits in memory storage and recall, aphasia, concentration, and finger tapping
speed; the last deficit was still detectable a year later in one group of mountaineers.
Limited evidence suggests that climbers with a high ventilatory response to hypoxia
(HVR) may be more susceptible to impairment than those with a lower HVR.
Key words
Hypoxia - brain - memory - ventilatory response to hypoxia
