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altitude sickness:see decompression sicknessdecompression sickness,
physiological disorder caused by a rapid decrease in atmospheric pressure, resulting in the release of nitrogen bubbles into the body tissues. It is also known as caisson disease, altitude sickness, and the bends.
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a pathological condition that arises upon ascent to great heights (above 3,000 m) resulting from lowered partial pressure of oxygen in inhaled air. The development of altitude sickness is associated with a disturbance of the function of certain organs and systems, chiefly of the cells of the higher sections of the central nervous system, resulting from oxygen starvation, or hypoxia. At heights under 3,000 m, a healthy person’s oxygen deficiency is compensated for by an increase in pulmonary ventilation (faster and deeper breathing), in blood circulation, and in hemoglobin and erythrocyte count in the blood. Further ascent brings on hypoxia, since the functions of the organism can no longer provide sufficient compensation. A shortage of oxygen in the surrounding air leads to lowered partial pressure of oxygen in the lungs and to lowered oxygen saturation of arterial blood. The major symptoms of altitude sickness include shortness of breath, heart palpitations, dizziness, noise in the ears, headache, nausea, weakness of the muscles, perspiration, blurred vision, sleepiness, and decreased stamina. The symptoms develop in phases, depending on the speed of ascent and on the functional state of the organism. Alcohol, fatigue, and insomnia lower the tolerance for great heights.
Treatments for altitude sickness include descent to a lower altitude, rest, cardiac medicines, and strong tea or coffee. In severe cases, inhalation of oxygen is called for. Inhalation of oxygen from a special apparatus while ascending to great heights prevents altitude sickness. Sports that increase the organism’s demand for oxygen and thus cause hypoxia develop the organism’s resistance to hypoxia. One variant of altitude sickness is mountain sickness. Along with an oxygen deficiency, other factors in mountain sickness are physical exhaustion, cold, and ultraviolet radiation. With acclimatization to the mountain climate, the symptoms of mountain sickness weaken. Relative stabilization of the physiological indexes begins after approximately a three-week stay in the mountains.
N. A. AGADZHANIAN