The effects of altitude on human physiology

Essay by tyrion-2High School, 12th gradeA+, April 1997

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Changes in altitude have a profound effect on the human body. The body

attempts to maintain a state of homeostasis or balance to ensure the optimal

operating environment for its complex chemical systems. Any change from this

homeostasis is a change away from the optimal operating environment. The body

attempts to correct this imbalance. One such imbalance is the effect of

increasing altitude on the body's ability to provide adequate oxygen to be

utilized in cellular respiration. With an increase in elevation, a typical

occurrence when climbing mountains, the body is forced to respond in various

ways to the changes in external

environment. Foremost of these changes is the diminished ability to obtain

oxygen from the atmosphere. If the adaptive responses to this stressor are

inadequate the performance of body systems may decline dramatically. If

prolonged the results can be serious or even fatal.

In looking at the effect

of altitude on body functioning we first must understand what occurs in the

external environment at higher elevations and then observe the important

changes that occur in the internal environment of the body in response.


In discussing altitude change and its effect on the body mountaineers

generally define altitude according to the scale of high (8,000 - 12,000

feet), very high (12,000 - 18,000 feet), and extremely high (18,000+ feet),

(Hubble, 1995). A common misperception of the change in external environment

with increased altitude is that there is decreased oxygen. This is not

correct as the concentration of oxygen at sea level is about 21% and stays

relatively unchanged until over 50,000 feet (Johnson, 1988).

What is really happening is that the atmospheric pressure is decreasing and

subsequently the amount of oxygen available in a single breath of air is...