High
altitude affects many people, past and present, around the world. Often, high
altitudes have dangerous effects on people who are not used to it. It may cause
hypoxia in many people due to the lack of oxygen that is being supplied to the
lungs (There is not less oxygen at higher altitudes, it is just less concentrated). This
is because as the altitude increases, air pressure decreases making it harder
for oxygen to permeate the lung membrane. Among others, consequences include difficulty breathing,
headaches, vomiting, and fatigue. Fortunately, our bodies have been perfecting
ways to deal with the stress of changing altitudes.
Short-term
adaptions to hypoxia and other altitude sicknesses are vomiting, fatigue, and
headaches. As our bodies are receiving less oxygen, they do their best to
compensate and, in turn, indulge minor pains (like the headaches) rather than
something more severe like death. This is considered a short-term adaption
because the symptoms of altitude sickness disappear once the person suffering
returns to his or her normal environment.
A
developmental adaption to high altitude is the increased production of
hemoglobin in the blood. The high level of hemoglobin in blood permits higher
levels of oxygen to be transported to the lungs, in addition to increasing lung
expansion. After hundreds of generations of dealing with the lack of oxygen,
Tibetans have perfected this development from birth, resulting in rosy cheeks.
People who have lived at high altitudes for many generations will certainly
have redder cheeks from birth than those who have only lived there for a short time.
A
facultative response to high altitude is heightened fitness. Many athletes
training for the Olympics are often coached at much higher altitudes than their
normal environments, because they believe it will result in a “short-term
developmental” adaption. As discussed above, with lower oxygen levels and air
pressure cause hemoglobin production to increase. This process allows athletes
to gain a normal fitness standard while at higher altitudes, and consequently
enhanced fitness at lower altitudes. However, their bodies have not been
structured to continue doing this like Tibetans and their enhanced fitness soon
fades back to normal.
A cultural
adaptation to high altitude is the practice of yoga and meditation by Nepalese
Buddhist monks. The deep breathing helps transport oxygen to the lungs at a
normal rate. Studies by the High Altitude Medical Research Centre have
concluded that yoga and deep breathing can reduce the effects of hypoxia in
those who practice it regularly.
Studying
human variation from this perspective allows us to understand how our bodies
adapt and function under different conditions. Scientists can see how bodies adapt to the
different environments and further understand what the environments may have
been like in the past. These studies also indicate that race would have no
explanation for the genetic changes seen across environmental clines. The
changes that have occurred genotypically and phenotypically are results of
people living in an area for a long period of time, regardless of who they were "racially." Race is a poor way to study adaptations, because there are so many
similarities between racial groups. Race itself is made up in order to describe
people who look different from one another, although there is more genetic
variation within a single racial group than between multiple. Environmental stresses
are the best way to understand the causes for skin color and many other genetic
variations seen around the world.
