Why? The Science of Athletics

HUMAN MECHANISM 73 excited by the hope of winning a contest is likely to do well. On the other hand a cold bath or painful emotion decelerate the heart action. That is why the athlete should not stand about stripped-out and letting his limbs get cold, and why the man who fears doing badly in the competition for which he is waiting is not likely to win. In this connection there is a genuine distinction between "anxiety" and "fear". The importance of these matters cannot be over– rated, since it is the alteration in the pulse-rate which adapts the heart action to the varying needs of the body, and the higher the pulse rate the greater will be the quantity of blood forced into the arterial system per minute. This energy-output of the heart is under the control of a special system of nerves which regulate the pace of its beat. I shall, however, have more to say about the "sympathetic", or involuntary, nervous system in a later chapter. We have seen already that during muscular exertion the heart and the circulation make their most important adjustments to meet the immediate needs of the athlete. They do this . by increasing many times the output of blood from the heart, both by accelerating the rate of heart-beat and by making more powerful the contraction of tHe heart at each beat. If, now, we think back to what the late Michael Murphy said regarding the relationship between two men with hearts beating at different rates per minute, but doing the same amount of work, and if, moreover, we re-examine the American experiments already referred to, we are bound to arrive at the conclusion that the heart-rate of a trained athlete is lower for a definite blood-output than that of an untrained person, when both are performing the same task. It should be remembered, however, that the divergence grows more pronounced as the exertion increases and becomes more prolonged. The explanation of what has just been said is to be