The greater the length of time that the body is in a fully acclimatized condition, the more habitual become the changes. Thus, upon exposure to a passive stress, the body undergoes a hierarchy of responsive changes, and eventually becomes fully acclimatized to the point that the changes become constant as well as permanent while residing in the environment. This full acclimatization is compromised by shorter periods of exposure. Generally, the shorter the time spent at altitude, the less dramatic are the acclimatizations and those which do have an opportunity to occur are quite transient. There are four main features that modify acclimatization responses.
Acclimatization involves all systems within the body.
A common error made by scientists and coaches is to focus only on part of the reactive process which often leads to erroneous conclusions. However, few physiological changes interact with other systems and may serve to moderate performance in a completely different way to when all factors are considered. Unless psychological, biomechanical, and physiological aspects of acclimatization are considered, a true understanding of altitude acclimatization will not result. Usually acclimatization occurs in degrees, the extent being dependent upon the severity of the environmental stress. The ever present problem of individuality arises to complicate generalizations about the effects of acclimatization.