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Effects of High Altitude on the Human Body

Abhijit Naik
There is no doubt about the fact that altitude sickness is one of the most prominent effects of high altitude on the human body, however, one should also take into consideration the fact that the detrimental effects of high altitude go well beyond it.

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High altitude is known to trigger a series of health effects on the human body, ranging from mild issues like insomnia, swelling of hands, dehydration, and decreased appetite, to severe issues such as stroke and cerebral edema. By and large, the problems that you are likely to face at high altitude depend on your ability to adapt to the atmospheric changes.

Why Does High Altitude Affect Our Body?

Basically, the human body is not equipped to handle the drastic change in the atmospheric conditions prevailing at high altitudes. These include rapid fall in temperature, lack of oxygen, change in atmospheric pressure, etc.

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The basics of climatology state that the temperature decreases with increase in the altitude, which implies that the temperature at the sea level is higher than the same at high altitudes in mountainous regions. The belief that lack of oxygen is the driving factor for most of the ill-effects of high altitude on the human body is basically an incomplete fact.
A wide majority of the effects can be attributed to the change in the atmospheric pressure. The fall in pressure hampers our ability to take in air, as a result of which our body doesn't get the required amount of oxygen, and it is assumed that lack of oxygen results in health problems. However, this makes our body susceptible to these problems.

High Altitude Effects on the Human Body

Some of the prominent effects of high altitude on the body include hypoxia, hypothermia, loss of ventilatory control, dehydration, etc. Changes in the atmospheric conditions at high altitudes hamper the functioning of several organs of our body.

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The cold dry air at such height can cause irritation in the airways. Diffusion of oxygen is hampered as a result of decrease in atmospheric pressure, thus making breathing difficult. At high altitude, even mild exertion can leave the person gasping for air.
Hypoxia, i.e., the deficiency of oxygen, can eventually result in pulmonary vasoconstriction and pulmonary hypertension.
Lack of oxygen in the body can also result in damage to the central nervous system, and eventually result in complications such as stroke or cerebral edema. Hypoxia also stimulates the production of erythropoietin―a glycoprotein that stimulates the production of red blood cells, and this, in turn, results in increase in hemoglobin.
At high altitude, the chances of thrombosis, i.e., the formation of blood clots inside the blood vessel which obstruct the blood flow and result in life-threatening complications, is also high. Owing to all these risks, being well-versed with some simple, yet effective altitude sickness remedies is always an advantage.

Medical Problems at High Altitude

Acute Mountain Sickness (AMS): Also referred to as altitude sickness, AMS is a pathological effect of high altitude on the human body, which usually occurs at an altitude of 2,400 meters (8,000 feet). If no proper medical attention is provided at the earliest, this can progress into high-altitude pulmonary edema (HAPE) or high-altitude cerebral edema (HACE).
Chronic Mountain Sickness (Monges disease): This condition generally occurs as a result of prolonged exposure to the extreme conditions prevailing at high altitude. This condition, which occurs as a result of excessive production of red blood cells in the body, is quite common in people who live in mountainous regions.
High-altitude Cerebral Edema (HACE): One of the most severe complications related to high altitude, high-altitude cerebral edema is known to result in swelling of brain tissue owing to fluid leakage, which can eventually result in death. The condition is generally preceded by acute mountain sickness.
High-altitude Pulmonary Edema (HAPE): Yet another health complication which occurs at high altitude, HAPE can result in accumulation of fluids in lungs, eventually resulting in death of the individual. Even healthy mountaineers are not safe from this condition, which generally occurs at an altitude of 2,500 meters (8,200 feet) and more.
High-altitude Periodic Breathing: One of the most common health issues at high altitude, periodic breathing is a phenomenon wherein an individual's breathing pattern is characterized by alternating deep and shallow breathing in sleep. At times, the person may even pause breathing for 5 - 10 seconds and resume it with a gasp.
The only way by which the severity of these health issues can be reduced is by acclimatization, i.e., adapting to the prevailing conditions. Generally, high altitude is categorized into three groups: high altitude (1500 - 3500 m), very high altitude (3500 - 5500 m), and extremely high altitude (beyond 5500 m).
At extremely high altitude, most of the functions of our body, including sleeping and digestion of food, are hampered. Beyond the extremely high altitude lies the death zone, where survival of human beings is virtually impossible.

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While it's at least possible to acclimatize to the regions at extremely high altitude by resorting to altitude sickness prevention measures, acclimatization in the death zone is out of question.