HIGH ALTITUDE

HIGH ALTITUDE

High altitude is the region of earth located at an altitude of above 8,000 feet from mean sea level. People can ascend up to this level, without any adverse effect. Characteristic feature of high altitude is the low barometric pressure. However, amount of oxygen available in the atmosphere is same as that of sea level. Due to low barometric pressure, partial pressure of gases, particularly oxygen proportionally decreases. It leads to hypoxia. Carbon dioxide in high altitude is very much negligible and it does not create any problem.

BAROMETRIC PRESSURE AND PARTIAL PRESSURE OF OXYGEN

AT DIFFERENT ALTITUDES

Barometric pressure decreases at different altitudes. Accordingly, partial pressure of oxygen also decreases and produces various effects on the body.

CHANGES IN THE BODY AT

HIGH ALTITUDE

When a person is exposed to high altitude, particularly by rapid ascent, the various systems in the body

cannot cope with lowered oxygen tension and effects of hypoxia start. Besides hypoxia, some other factors are also responsible for the changes in functions of the body at high altitude.

Factors Affecting Physiological Functions at High Altitude

1. Hypoxia

2. Expansion of gases

3. Fall in atmospheric temperature

4. Light rays.

 EFFECTS OF EXPANSION OF GASES ON THE BODY

Volume of gases increases when the barometric pressure is reduced. So at high altitude, due to the

decreased barometric pressure, volume of all gases increases in atmospheric air, as well as in the body.

At the sea level with atmospheric pressure of 760 mm Hg, if the volume of gas is 1 liter, at the height of

18,000 feet (where atmospheric pressure is 379 mm Hg), it becomes 2 liter. And it becomes 3 liter, at the

height of 30,000 feet (where atmospheric pressure is 226 mm Hg). Expansion of gases in GI tract causes painful distention of stomach and intestine. It is minimized by supporting the abdomen with a belt or by evacuation of the gases. Expansion of gases also destroys the alveoli. During very rapid ascent from sea level to over 30,000 feet height, the gases evolve as bubbles, particularly nitrogen, resulting in decompression sickness.

EFFECTS OF REDUCED ATMOSPHERIC TEMPERATURE

Environmental temperature falls gradually at high altitudes. The temperature decreases to about 0°C

at the height of 10,000 feet. It becomes –22°C at the height of 20,000 feet. At the altitude of 40,000 feet, the temperature falls to –44°C. Injury due to cold or frostbite occurs if the body is not adequately protected by warm clothing.

EFFECTS OF LIGHT RAYS

Skin becomes susceptible for injury due to many harmful rays like ultraviolet rays of sunlight. Moreover,

the sunrays reflected by the snow might injure the retina of the eye, if it is not protected with suitable tinted glasses. Severity of all these effects depends upon the speed at which one ascends in high altitude. The effects are comparatively milder or moderate in slow ascent and are severe in rapid ascent.

Post a Comment

0 Comments