Exercise in education and medicine / by R. Tait McKenzie.

  • R. Tait McKenzie
Date:
1909
Catalogue details

Licence: Public Domain Mark

Credit: Exercise in education and medicine / by R. Tait McKenzie. Source: Wellcome Collection.

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    excreted or stored up in the tissues as fat. If training be severe, this natural horde of fat is speedily expended, and a man in fine athletic condition is always below his normal in fatty tissue. Athletic training aims to produce a machine to run, leap, fight, or row, and fat would only be an encumbrance, so that a man in fine athletic form would not be in the best con¬ dition to resist the siege of an exhausting infection, like typhoid fever or pneumonia, where the stored-up fat of the normal individual becomes his most valuable asset. The loss of weight during athletic exercise may be from five to eight pounds in less than half an hour, a loss which is continued after exercise is stopped if no food or drink is taken. In a series of observations made on foot-ball players during practice at the University of Pennsylvania I found that the loss averaged about three pounds, the highest being 5.1 pounds and the lowest .8 pounds, the weights being taken immediately before and after exercise. The men were then wrapped in blankets or allowed to sit around for an hour, and showed a further loss of one-half pound, the greatest loss being .9 pounds and the smallest nothing. In no case was any gain found.1 It has already been shown that the first two organs to act in the elimination of the poisons of muscular waste are the lungs and the skin, the former giving off heat, C02, and water vapor, and the latter, water, urea, and other constituents of minor importance, in addition to neutralizing the heat produced by muscular action through evaporation. This loss of weight from the skin and lungs goes on even during sleep, as shown by the delicate bal¬ ance used by Warren P. Lombard in his experiments2 (Pig. 13). From 107 observations on healthy men averaging 64.5 kilos in weight he concludes that the loss of weight is 0.692 gm. a minute, of which .525 is from the air passages and .166 or about 24 per cent, is from the skin. The elimination by the skin alone was obtained by holding the breath in expiration. 1For the carrying out of these experiments I am indebted to my assistant, W. J. Cromie. 2 Reported at the Siebenter Internationaler Phvsiologen-Congress, Heidelburg, I9°7*