The present section deals with the use of
muscular activity for its hygienic effect upon the body as a
whole; the next section with its employment for special purposes.
Exercises undertaken for their general good effect are frequently
spoken of as "hygienic"; the term is, however, objectionable,
and we shall speak of them as general muscular exercises.
General muscular exercise is of hygienic value because it
produces the physiological results which have been enumerated
in the preceding section, -results which have been shown to constitute
essential elements of the normal internal environment of the
cells of the body. To review the separate offices of this ministry
to the normal conditions of the body:
- General exercises should produce to a considerable extent
those physical and chemical changes which accompany muscular
contraction, with the resulting effects upon the physiological
condition of the muscle itself and upon the general internal
environment, the blood and lymph.
- They should exercise, and so train, the heat-regulating mechanism.
- They should tend to relieve vascular congestion in internal
organs, bringing the blood in larger quantities to the skin.
- They should afford training to the heart.
- They should increase the ventilation of the lungs.
- They should increase the flow of lymph in the lymphatics,
and thereby improve the environmental conditions of all the cells
in the body.
- They should exert a favorable influence upon the digestive
processes, promoting proper secretion and absorption, and tending
to prevent unhealthful conditions leading to constipation.
Such being the physiological ends sought for, we may conclude,
as to the character of such exercises:
1. They should consist of rhythmic rather than sustained
contractions. These involve less fatigue, are more enjoyable,
and especially facilitate the flow of blood and lymph.
2. They should be vigorous, somewhat prolonged, and should
usually be continuous. A brisk walk or a run meets most demands;
so do bicycling and many games. The strolls or saunters which
are too frequently mistaken for exercise do not meet the reasonable
hygienic demands of the body; they involve only an insignificant
increase of chemical activity in the muscles, they hardly affect
respiration, they do not train the heart; in short, they do not
produce adequate physiological effects to accomplish hygienic
3. They should involve considerable movement on the part
of the trunk as well as the limbs. Many excellent forms of
exercise, such as bicycling, are somewhat deficient in this respect.
It is not meant that sudden and violent trunk movements are called
for, but that hygienic exercise should bring full change and
relief from the constrained positions of the trunk imposed by
the sedentary occupations of modern life. A vigorous walk, with
its accompanying increase of breathing and trunk movements, fencing,
and games which involve the throwing and catching of a ball are
especially good in this respect.
4. They should be accompanied by full and free respiration.
The importance of this requirement needs no comment. Constrictive
clothing should not be allowed to interfere, and, as far as possible,
the trunk should be held erect, the neck and shoulders back,
so as to permit the freest movement of the upper ribs.
5. It is advisable not to confine oneself wholly to one
form of exercise. Similar considerations to those which hold
in the choice of food apply to some extent to exercise. At the
same time it must be admitted that perfect health can frequently
be maintained to old age by using only one kind of general exercise,
such, for example, as walking.
7. Considerations Concerning
The relation of general exercise to fatigue is a matter of
considerable interest and also of importance in correlating muscular
work with the other work of life. Fatigue of the whole organism
is a very complicated matter and involves much more than the
total amount of chemical change in the muscles and of the resulting
waste products in the system as a whole. We, may, for example,
be made very tired by unpleasant sensations from the joints and
tendons, or by walking in shoes which do not permit free play
to the bones, ligaments, tendons, and muscles of the foot; and
this, even when the amount of muscular exertion involved may
have been slight. It is well known that merely standing still
for a time will frequently cause more fatigue than will a longer
time spent in walking,
Again, some forms of exercise throw a relatively large share
of the total work on some muscle or small group of muscles, while
others distribute the total work more evenly over larger groups.
Walking and running are very unlike in this respect; in the former
the weight of the body must be lifted from the ground with each
step,-especially when we walk very erect,-by the extensor muscles
of the leg, and chiefly by the extensors of the ankle joint;
running, on the other hand, consists in a continual falling forward
and the restoration of equilibrium by a more general action of
the muscles of the body as a whole. A walk of four and a half
miles an hour is much more fatiguing to a person in good training
than a run of four and a half miles an hour, because in the former
case a few muscles are thrown into very vigorous contraction
and so give rise to severe local sensations of fatigue, sometimes
accompanied by cramps in the muscles.
8. Some Examples of General
Bicycle riding is remarkable for distributing the total work
over large numbers of strong muscles, so that the amount done
by each is relatively small; consequently, where there is but
little hill-climbing or no strong head winds, local fatigue is
but slight, although the total work done by the body is considerable.
Actual measurements of the carbon dioxide excreted have shown
that this is much greater per minute in a ride of eight miles
an hour on a smooth level track, than in walking three and a
half miles an hour; in other words, the total work is greater.
The well-known increase of perspiration brought about by such
moderate riding points in the same direction; the chemical changes
in the body are greater and so is the associated heat production;
and yet any cyclist knows that the conscious fatigue of the ride
is as nothing compared with that of the walk. Moreover, in wheeling
the weight of the body is not supported on the feet, and we are
thus to a large extent relieved from the unpleasant sensations
produced by pressure and jar in the ankle and knee joints. It
is a characteristic of moderate or even fairly vigorous bicycle
riding that it produces a maximum of chemical change with a minimum
of fatigue. This is of great practical importance. The larger
production of carbon dioxide involves deeper breathing, and,
as the student now well knows, increased work on the part of
Within proper limits this is, of course, good for the heart;
there is some danger, however, that in the absence of conscious
fatigue we may throw upon that organ more work than is good for
it, and medical experience leaves no doubt that many cases of
injury to the heart have resulted from injudicious cycling; that
is to say, from "scorching" against strong head winds
and in "showing grit" by refusing to get off and walk
up very steep hills. There are occasions when it is not wise
to be too ambitious, and when "discretion is the better
part of valor."
9. Some Examples of General
Somewhat similar considerations apply to most of our more
active games, such as basketball, football, tether ball, hockey,
polo, etc. They are perfectly safe for healthy people when not
played more vigorously than the training of the heart justifies;
the fact that there is an element of danger in them is no reason
why they should not be used, but it is a very good reason why
they should not be worked to extremes, and especially why we
should be sure, from competent medical advice, that there is
in those who play them no organic trouble to begin with, and
that players are in good training when they play most intensely.
The choice of the kind of muscular work and exercise involves
so many considerations other than those which are strictly physiological
and hygienic that it is impossible to give in an elementary treatise
like this any detailed discussion of the special merits and defects
of each. We often have other aims in view besides the purely
hygienic; thus the group games, such as football, baseball, basketball,
hockey, etc., train the spirit of cooperation and may be made
useful means of moral training. In camping in the woods, canoeing
is not simply a means of exercise, but also a means of transportation;
and under other conditions the same thing is true of horseback
riding, rowing, etc. Wood chopping, digging, porterage, and plowing
are valuable means of livelihood. It is believed, however, that
the principles here given will help the individual to form a
correct judgment as to whether his work in life supplies him
incidentally or inevitably with the needed general muscular activity
for hygienic purposes, and, if it does not, to plan to meet the
The combination of muscular exercise with some other pursuit
is highly desirable, and when practicable often simplifies the
hygienic conduct of life. But it is nothing short of a hygienic
misfortune to lose the youthful love of activity for its own
sake. It is well as we grow older to have golf, or a horse to
be exercised (!), or a fishing preserve in the woods, to "take
us out in the open air" and make us use our muscles. But
a human being who is dependent upon something of this kind to
drag him into activity cuts a sorry figure from a moral standpoint.
Man's highest distinction is the fact that his actions may arise
so largely from processes of psychic life within rather than
from some immediate stimulus from without. The proper hygienic
conduct of life involves moral fiber as well as physical fiber,
and this is especially true of that absolutely essential part
of hygienic conduct which depends upon the use of organs like
the skeletal muscles, which are so largely subordinate to the
commands of the will.
10. Importance of Walking as
a Means of Exercise.
In their enthusiasm for athletic games and outdoor sports
in youth, and for other outdoor activities in middle life, the
American people are always in danger of losing their love for
the various forms of walking, such as tramping and mountain climbing.
Walking is the one form of general exercise for sound people
which can always be had for the taking. For this reason, if for
no other, it should ever be a part of all sound physical training
to conserve the love of tramping and the ability to walk. Apart
from the obvious fact that it is in this way that we can get
close to nature and the real beauty of the world in which we
live, the possession of the love of the activity involved is
one of the most precious possessions of our hygienic life. The
man or woman who does not keep and improve this power by use
must look forward to the same fate as the servant in the parable
who hid his talent in a napkin, only to have it taken from him
in the end.
11. Fresh Air not a Substitute
for Muscular Activity.
A word of warning is needed against the folly of supposing
that fresh air is a substitute for muscular activity. Fresh air
is one of our greatest hygienic blessings, and it is very desirable
to live an outdoor life as far as possible. But too many think
that lounging in the shade, or riding in the open air in an automobile,
a carriage, or an electric car, does for them what muscular exercise
alone can do. Especially as age creeps over us and the love of
activity wanes from its disuse, more and more does the idea grow
upon us that "fresh air" is everything. To many the
possession of a comfortable carriage and a pair of thoroughbreds
is a misfortune. At one of our most beautiful summer resorts
someone said to a local physician, "Medical practice at
such a place as this must be very unremunerative." "By
no means," replied the man of experience; "people come
here where they are tempted to overeat; in the place of exercise
they lie back on the cushions of their carriages while they are
driven about; their adipose tissue increases rapidly, and very
soon it is true that to no class of people is the doctor so absolutely
essential as to them." The student can easily make the application
for himself. Indigestion, fatty degeneration, insomnia, loss
of appetite, nervous prostration, and kindred ills rarely come
to those who labor with their hands; and these ills can be largely
prevented, even in those who must engage in sedentary occupations,
by a wise and intelligent conduct of the physical life, and especially
by the daily employment of an hour or so of vigorous general
muscular activity properly correlated with the other work of
Hough T & Sedgwick WT (1906). Muscular Activity (Chapter
XVII), The Human Mechanism Its Physiology and Hygiene and The
Sanitation Of Its Surroundings, Ginn & Company, pg 314-320.