The Nature of Fatigue

The condition of fatigue is so familiar that explanations con-
cerning it hardly seem necessary, but since the term is often in-
definite and inexact in its use a brief review of the topic and of the
meaning employed in this report is attempted.

Simply stated, fatigue is that condition induced by work which
results in a diminished capacity for work. The mass of scientific
data dealing with the types of fatigue; the symptoms and causes;
organic and chemical changes which take place in the body; and
the effects of such factors as disease and environment is too lengthy
and complex for comprehensive presentation here. As a back-
ground, though, it seems wise to summarize some of the general
facts proved by careful investigators in the field.

I. Regardless of the type of work undertaken, the fatigue which
results from it is both specific and general. Not only are the muscles
and organic systems actively engaged in the effort strongly affected,
but the whole individual becomes involved, including all of his
body and his mental processes as well.

2. As fatigue products increase due to continued work, all volun-
tary muscular contraction becomes slower and less intense.

3. Extension of the work period ultimately develops fatigue
products of an amount sufficient to cause complete cessation of the
effort. Should one possess enough will power or emotional drive to
attempt continuation of work after maximum fatigue is reached
exhaustion or collapse ensues and all voluntary muscular control
ceases. Collapse, however, may be likened to a fuse in an electrical
circuit in that it cuts off the flow of energy before damage to more
important installations can be done. In other words, fatigue is
one of nature’s most effective mechanisms of self-preservation
because it institutes inhibitions well within the bounds of safety.

4. The onset of fatigue is postponed; its inhibitions reduced;
and recovery hastened when one is conditioned to the task. This
means, of course, that frequency and regularity of vigorous activity
builds organic and muscular systems which both resist the onset
of fatigue and allow quicker recuperation from its effects.

5. Rest is the best and only certain cure for fatigue. Prolonged
rest, though, tends to counteract the conditioning developed by
exercise. A capacity to perform hard work over an extended period
of time is the goal of physical fitness programs. It is achieved by

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