For most of us, exercise is confined to tennis and golf. And in their respective fields they are perfect. They develop, besides the all-around work-out of all the muscles of the body, those mental attributes which are quite as important results of athletic endeavor as muscular strength, endurance, accuracy of eye and arm, and skill.
The question of endurance is largely a question of heart power. The ability to keep on movingrunning or any form of violent exerciseis a matter of “wind.” And as every athlete knows, wind can be developed. In fact, the principal aim of training is not to increase the strength of the muscles involved, but to increase wind.
Since muscles can work indefinitely if they have enough oxygen, and since the trick of getting them enough oxygen depends on the heart pumping enough blood charged with oxygen to them, the result of training is to increase the strength of the heart muscle and its ability to pump out more blood each minute without tiring.
The heart in its turn is nourished by blood vessels. And these vessels diminish in number and size from birth to old age. It is possible to inject these arteries with a paste which throws a shadow on the x-ray so that all the blood vessels of the heart can be seen as in a transparency, as shown in the accompanying illustration. The heart of youth is a thick meshwork of arteries. But the heart of a man of 50 shows great spaces where no vessels seem to go at all. They have been blocked up and absorbed.
For that reason tennis is the game for youth and golf the game for the middleaged. The sudden demands that the running, leaping and pounding of tennis make on the heart are too much for the scanty vessels of the middleaged. I used to be a very enthusiastic tennis player, but in the times I have tried it lately some inner voice has kept saying at about the third set, “The next is going to be your last set.”
But golf makes no such imperative drafts on the heart. Even so, as time goes on, it is not advisable for those past 50 to set out to show how many holes they can play. The “I played 36 holes today” business is all over for them.