The Pulse After a Marathon Race

The question of the possibility of producing alternation of the pulse by very vigorous and prolonged exertion was the incentive to a study of the pulse of twenty men who ran the annual Boston Marathon of 25 miles from Ashland to Boston, April 19, 1916. Myocardial exhaustion resulting from damage such as that produced by arteriosclerosis or syphilis has been shown to be an important cause of alternation of the pulse. The greater the strain on such a heart, the more marked is likely to be the alternation. The strain necessary to sustain a high blood pressure is especially likely to bring out alternation. Extreme and prolonged tachycardia, as in auricular flutter or paroxysmal tachycardia, may result in pulsus alternans. But it has never been shown, so far as I am aware, that alternation has been found in the pulse of a normal individual after severe exertion. Von Tabora¹