Why? The Science of Athletics

CONSIDERATIONS IN RELATION TO COMPETITION !49 perhaps a long way ahead, so far as the time-factor in relation to the particular event, or race, is concerned. We know that a person leading a sedentary life gets into the habit of using the lungs to only about a tenth of their capacity and that exercise permanently, and limbering-up temporarily, increase efficiency by increas– ing the depth of tidal breathing. We know, similarly, that the heart rests and recovers between each beat, and that when a .man is sitting still it beats 72 times to a minute and throws about 5 pints of blood ; while in ordinary life there is always a certain amount of what is called "vagus tone", that is to say, the vagus centre is quietly and constantly at work keeping the heart-rate down. But for athletic performance our sympathetic nervous centre must be stimulated, and we have got to -safeguard the heart against that sudden up-rush of the heart-rate which comes from the excitement of the contest and the secretion by the suprarenal glands of adrenalin which emotion releases in the blood. And so, to minimize the shock at a time when there is but little excuse for emotional strain, we limber-up so that the nervous system automatically removes the vagus effect and the heart-rate increases. After that the sympathetic nervous system becomes active, also automatically, and the heart-rate rises still higher. If the athlete is a very highly strung individual, much given to anxiety regarding the forthcoming event, then he will be already in an emotional state and the presence of adrenalin in his blood-stream will be acting upon the heart to quicken its rate and strengthen its beat. A powerful heart-beat is an important concomitant of success, and both in the limbering-up period and during the excitement of the struggle the release of adrenalin into the blood-stream is important, because one of its effects is to stimulate the heart to greater activity. Finally, the rise in temperature of the whole body acts to stimulate the heart and helps it to adjust its action to the demands of the muscles for more blood.