Influence of high altitude exposure on the immune system: a review.

High altitude may be defined as elevations as low as 1500 meters to those as high as 8800 meters. Very few studies have been conducted so far at high altitude for the specific purpose of monitoring different immune parameters in humans. Military personnel and mountaineers may be required to perform in environmental extremes such as high altitude. The stressors they experience are numerous and varied, e.g., high altitude, humidity and the availability of food and water, prolonged moderate to heavy physical activities, limited or inadequate sleep, increased susceptibility to infection and injury, etc. In this article we review the immunological consequences of high altitude exposure.