Changes in the Composition of the Urine after Muscular Exercise.*

The effect of strenuous muscular exercise on the body has been studied extensively. The responses of many of the mechanisms which take part in attempting to furnish oxygen and fuel and to remove carbon dioxide and other waste products have been analyzed in considerable detail. Studies on the respiratory exchange, the blood, and the urine have contributed much toward furnishing us with a detailed knowledge concerning the extent to which the mechanisms for maintaining neutrality in the organism are brought into play. The work of Barr and his collaborators (1923, a, b, and c) has strikingly demonstrated the relatively great variations in the reaction of the blood brought about by short periods of strenuous exercise. One would expect that such large variations in t,he blood would be accompanied by a response by the kidney resulting in similarly great changes in the composition of the urine. The data in the literature which permit such comparisons are, however, meager and sometimes inconclusive and contradictory. In most of the older work, long periods of exercise and long periods of urine collection were employed. We believe that our studies of short periods of strenuous exercise and short periods of urine collection have yieldeddata of greater value for showing the immediate effects of the exercise and attempts at compensation on the part of the body.