CHANGES IN URINARY EXCRETIONS DUE TO PROLONGED STRENUOUS EXERCISE IN WOMEN / 体力科学

ABSTRACT

As well known, the adreno-sympathetic hormone - catecholamine - plays an important role in maintaining the stability of “milieu interieur”. Accordingly, a marked change may occur in catecholamine secretion in case of prolonged strenuous exercise such as marathon race where is required remarkable augmentation of cardiovascular functions. The authors had an opportunity of examining the physiological functions of all the participants in the First Tokyo International Women Marathon Race held on November 18, 1979, and collected urine samples from them before and after the race to evaluate the physiological load of the race in each woman participant by changes in urinary excretions of catecholamine metabolite (VMA) and some other substances.<BR>As for the subjects of examinations, 19 foreign runners were 31.1 years of age on the average (ranging from 20 to 48 years) and their average Rohrer's Index was 119.0, while 33 Japanese runners were 27.8 years of age on the average (ranging from 18 to 42 years) and their average Rohrer's Index was 125.8. The urine samples at rest were collected at 8 a.m. on the day before the race after more than 10 hours fasting, and the samples after running were collected in 30 minutes after finishing the race. Just after the collections, the authors made determinations of the urine volume and pH and qualitative tests for sugar, protein, occult blood, Keton bodies and bilirubin. Then the determinations of VMA were made by Pisano's method. The resulte obtained were compared among six groups classified by the performance, viz., the order of the arrival. The classification was made as follows 1) 1-5, 2) 6-10, 3) 11-15, 4) 16-20, 5) 21-25 and 6) 26-46. The comparison was also made between the foreigners and the Japanese.<BR>Results:<BR>Although there could be no significant correlation between the performance and the age or physique, the Rohrer's Index was smallest in Group 1) and largest in Group 6) .<BR>The qualitative urine tests disclosed no marked change due to the running but protein less than 300 mg/dl was detected in the urine after running in 31 out of 40 runners. This fact seems to suggest that their physiological loads were considerably heavy. The urine volume on the average showed a decrease from 41.5 ml/hr at rest to 16.3 ml/hr after running, viz., 60.7 % decrement. The decrement was 53.2 % in the foreigners while it was 65.3 % in the Japanese. The urine volume was rather larger in Groups 5) and 6) than in the others. The urine pH on the average showed a decrease from 6.4 at rest to 5.6 after running, viz., 12.5 % decrement, and the decrement was 6.9 % in the foreigners while it was 14.9 % in the Japanese. Regarding the relation between the performance and the urine pH, there could be noted a tendency, the upper the ranking of the group, the smaller the change in pH.<BR>The urinary excretion of VMA on the average of all the runners showed a striking increase from 155.8 mg/hr at rest to 383.1 mg/hr after the running. The increase due to running was 121.4 % in the foreigners while it was 144.1 % in the Japanese. Regarding the relation between the performance and the VMA excretion, Group 1) showed no increase in the excretion on the average, while the other groups generally showed 100 % - 200 % increase in the excretion.<BR>On the basis of the above-mentioned findings, it was presumed that the physiological load of the marathon race was heavier in the Japanese runners than in the foreign runners, and in the lower ranking groups than in the upper ranking groups of the performance. In other words, the foreigners who showed excellent performance seemed to be highly adapted to the prolonged strenuous exercise by training and to have a regulatory mechanism of metabolism so efficient as to cope with heavy physiological load by small increase in catecholamine secretion.