No abstract

The effect of exercise on renal function has been the target of numerous research projects, many of which have recently been reviewed by Herlitzka (1). It is generally agreed that exercise exerts an antidiuretic effect, that it depresses urea clearance, and that it increases the specific gravity of the urine. With the introduction of diodrast and of para-amino hippuric acid it became possible to estimate renal plasma flow with considerable accuracy, but these newer methods have not been applied extensively to the question of the effect of exercise.In order to obtain quantitative information on the phenomenon a method was devised for following changes in renal plasma flow before, during, and after standard exercise of varying de at 10 per cent grade. The energy outputs at these levels of work, expressed as oxygen consumption per square meter body surface per minute, are 419, 612 and 1070 cc. The first two levels placed no great strain even on a strictly sedentary individual. The third and highest level taxed normal, active male students only moderately but caused considerable discomfort in subjects accustomed to little or no strenuous exertion. The arm being used for injection of the clearance substance was kept in a relatively fixed position during exercise by having the subject rest his hand on the edge of a shelf placed directly in front of him and adjusted to a point several inches below the level of the shoulders. With the arm thus partly immobilized, the energy outputs for a given treadmill speed and grade are about one to 2 per cent less than if the arms are allowed to swing free. The results, however, are comparable from experiment to experiment since they were obtained under identical conditions; the only variable was the level of exercise being investigated.The conditions under which renal plasma flow was followed during recovery were the same as those used for determining basal values. The subject walked a few feet to the bed after completing the work on the treadmill, and was required to lie immobile for the rest of the experiment. The constant injection apparatus was moved with the patient without interrupting the injection of the test substance.The time sequence and complete data for a typical experiment in this series are given in Table I. MATERIAL Nine subjects were employed in the study. All were healthy male university students or instructors aged from 21 to 32 years. There was no evidence of renal disease in their histories or in the results of their urinalyses. Resting blood pressures were within the normal range in the entire group.All clearance values were corrected to 1.73 sq. m. of body surface using the formula of Dubois for total body surface.Basal values were determined for two or three consecutive clearance periods in each experiment, the usual number being three. More than one experiment was done with eight of the nine subjects, and in six subjects, experiments were repeated six or more times. In order to gain some insight into the reliability of the method, all available basal data w...

No abstract

No abstract

No abstract