Abstract

With increasing altitudes, athletes will experience marked decreases in endurance performance; occasionally they will develop high-altitude illness, and in rare cases, even life-threatening forms. Thus, the understanding of the physiological basis of performance diminution and the development of high-altitude illnesses is important for the implementation of appropriate preventive and therapeutic measures.Aerobic exercise performance decreases upon ascent to altitude, whereas anaerobic performance remains unchanged. Typically, sub-maximal but not maximal exercise performance improves following 1-3 wk of acclimatization due to an increase in arterial oxygen saturation and haemoglobin concentration from increasing ventilation and decreasing plasma volume, respectively. The falling PiO2 and the related decrease in PAO2 and SaO2 with increasing altitude not only affect exercise performance but are also mainly responsible for the development of high-altitude illnesses. Whereas acute mountain sickness (AMS) represents the most common illness, which is benign and self-limiting in nature, high-altitude cerebral edema (HACE) and high-altitude pulmonary edema (HAPE) are rare but severe life-threatening illnesses. Beside the most important general preventive measures like pre-acclimatization, slow ascent to altitude, sufficient intake of fluid and carbohydrates, and avoidance of alcohol and nicotine, some drugs such as acetazolamide, COX inhibitors, dexamethasone, nifedipine or salmeterol have proved efficacious in the prevention of altitude illnesses in subjects susceptible to them. The same drugs, oxygen, hyperbaric chamber, and evacuation to low altitude are effective for treatment of high-altitude illnesses. Verf.-Referat