December 10, 1942.

2 am happy to reply te your favor of the 7th instant.
I am heartily in accord with the program of every healthy individual
walking at ieast three miles a day, and five if possible. Certainly
no one can keep in good physical condition without using the large —
muscle group of the bedy. When you walk you "breathe with your legs".
Walking, running, jumping, leaping, vaulting, climbing and crawling
are the fundamental activities of the human animal.

the reason that so many boys have their knees and ankles
injured in athletic contests is because the boys have. practically quit
using their legs and have resorted to the automobile in getting to
school and the movies. when the legs are used in walking the large
fundamental muscle groups are used, causing a muscular activity and
thereby stimulating metabolism.

Metabolism is that process of building up and tearing down
that is constantly going on in our bodies when we are active. Catabolian
is tearing dow and anaboliam is building up. Both precesses are known
as metabolism. When the oxygen is depleted in the tissues after exercise
it doubles carbon dioxide and other waste products. This stimulates the
nerves to activity and causes a reaction which causes increased breath-
ing and heart action. Oxygenated bleod is pumped by the heart through
the arteries and capillaries to the depleted area so that the tissues

can be replenished with food and oxygen. ‘Therefore, we build up by
tearing down.

As the roots of a giant oak sends tentacles into the earth
to fasten themselves around a giant boulder to make the tree more sucure ©
in its attachments, so do the ligaments and tendons attached to the rough
beny prominences to make more secure the muscular attachments in our
- bodies. By developing strong muscles we are enabled to stand off the
ravages of disease and old age much more effectively than when we fail
to take regular systematic and fatiguing exercise.

No person should undergo strenuous or long fatiguing exercise \
until he has an examination by a physician. But if the vital organs are
pronounced in good physical condition by a physician, an individual can
exercise strenuously without hurt to themselves.