Special Foods, Sugar, Gelatin (glycine), Salt, Potassium

Sugar

The athlete in training should have extra carbohydrate in his diet. An additional quantity of sugar fed to an athlete who is to perform only a short bout of work will not increase his efficiency nor forestall early exhaustion. The efficiency of 10 minute work periods on a bicycle, ergometer is not affected by feeding glucose or sucrose. In a series of weight lifting tests the ingestion of glucose had no appreciable effect.

The administration of sugar may improve performance in athletic events which are so strenous and prolonged as to result in hypoglycemia and extreme fatigue. Thus, subjects who worked to the point of exhaustion on a bicycle ergometer were able to continue their exertion for an additional hour if hypoglycemia was prevented. A phenomenal continuous work output was recorded in a dog who was given glucose at frequent intervals. Glucose has been shown to have very beneficial effects in marathon races.

In certain circumstances a large intake of glucose can limit physical output. If physical work is started after the ingestion of a considerable quantity of glucose, at the moment when tile post-prandial blood sugar curve begins to fall, a sudden and considerable drop in the sugar content of the blood may sometimes hamper the performance of the work.

Gelatin (glycine)

The theory that glycine, which constitutes about 25 per cent of gelatin, enhances the supply of energy-yielding phosphocreatine by promoting the formation of creatine in the muscles has led to the belief that gelatin may increase muscular power and endurance. Gelatin administration, however, is entirely without effect on the composition of muscle, not only with respect to creatine but also as regards creatine phosphate, hexose phosphate, total nitrogen, glycogen and adenosine triphosphate. 7 A critical review of conflicting reports on this subject 8 indicates that if an effect of glycine exists it must be temperamental in its occurrence.

Salt

Heavy physical effort in great heat entails a loss of salt, especially sodium chloride, of such magnitude an to cause a complex of symptoms variously described as miner's cramp or heat cramp. In such cases, an additional ration of salt becomes essential. In prolonged athletic contests in which excitement and increased body temperature result in a loss of body salt along with water, sodium chloride given with water during the contest will prevent a salt deficiency and the consequent reduction in standards of performance. Salt feeding during a contest is especially indicated if the salt content of the participant's diet has previously been cut down in order to prevent thirst. In short sporting events doses of sodium chloride arc seldom of advantage. Salt in concentrated closes may cause discomfort, nausea, and vomiting.

Potassium

Exercised muscles lose potassium as fatigue develops. Injection of potassium chloride delays muscular fatigue and restores the working capacity of a fatigued muscle. Execess potassium is rapidly excreted by the kidneys, so that an attempt to store reserves of potassium by massive doses is useless. Instead, ample potassium should be provided in the diet in order to replace losses during hard muscular work.