Human behaviour and development under high-altitude conditions.

Although we are far from a universally accepted pattern of impaired function at altitude, there is evidence indicating motor, perceptual, memory and behavioural deficits in adults. Even relatively low altitudes (2500 m) may delay reaction time, and impair motor function. Extreme altitude exposure (>5000 m) may result in more pronounced impairment that can persist after returning to the lowlands. Research into the effects of altitude exposure earlier in development is lacking by comparison. Un-acclimatized children can suffer from acute mountain sickness, and, in native populations born at altitude, subtle cognitive and behavioural deficits suggest incomplete adaptation to hypoxia. The study of neurobehavioural functioning at altitude may provide important information about the effects of clinical hypoxia on the human brain and behavioural development.