Why? The Science of Athletics

I 18 WHY?-THE SCIENCE OF ATHLETICS the truth ofwhat has been written in these pages concerning the need for training the sympathetic nervous system. Nerves and the Heart The rate at which the heart beats is regulated by special sets of nerves belonging to the sympathetic nervous system, which controls also the working of the "smooth" muscles of the body and the secretion of the glands. There are two kinds of sympathetic nerves regulating the heart rate. The vagus division reaches the heart, via the vagus nerve from a centre situated at the base of the brain and this division has an inhibitory, or braking, influence. The other division, acting always to increase the heart rate, comprises the accelerator nerves, and has its origin in the upper part of the spinal column. Both sets of nerves are constantly operative, and between them adjust the delicate balance of the heart rate. It is the inhibitory influence of the vagus nerve that safeguards the heart against undue acceleration, such as would lead to an insufficient supply of blood circulating through the organs and tissues of the body. Such diminu– tion of the blood-stream might not unduly affect some parts of the body for a short period, but the brain must at all times be kept well fed, otherwise its needs will quickly be made plain by the failure of the numerous nervous controls of the bo.dy. Coaches should remember that fainting is caused by the temporary slowing of the heart rate through temporary overaction of the vagus nerve on the heart, and that sudden pallor exhibited by an athlete indicates an insufficient supply of blood to the capillaries under the skin, and, again, there is evidence that the heart action is temporarily inadequate. Now that we are reaching the conclusion of our purely elementary considerations of human mechanism we are beginning to understand no doubt that, although ther are times when we are more "mind-bodies" than "body– minds", the fact yet remains that the two are inseparable, since the; one cannot survive without the help of the other._