altitude sickness

altitude sickness

[′al·tə‚tüd ‚sik·nəs]

(medicine)

In general, any sickness brought on by exposure to reduced oxygen tension and barometric pressure.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

altitude sickness

In general, any sickness brought on by exposure to reduced partial pressure of oxygen and barometric pressure.

An Illustrated Dictionary of Aviation Copyright © 2005 by The McGraw-Hill Companies, Inc. All rights reserved

The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Altitude Sickness

 

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

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.