EFFECT OF PHYSICAL EXERCISE ON MINERAL METABOLISM / 体力科学

ABSTRACT

Six healthy boatmen of students were examined their mineral metabolism in urine and serum over three different periods consisting of three successive days in every two weeks, during the training camp of boat race event. The first examination period (I) was 11-14 June as ordinary time while attending school, the second period (II) 25-28 June as relatively light exercise time in training camp while attending school, and the third period (III) in summer vacation 9-12 July as hard physical exercise time. Every two hour urine was collected during the three days of each period and the blood from the cubital vein of the examinees was sampled at noon of the second day in each period.<BR>[A] Urinary excretions per 24 hours in the three different periods.<BR>(1) No definite variation was seen in pH. The value of the Donaggio's reaction was found greater in periods II and III compared to that of period I.<BR>(2) Urine volume did not show any significant variation, but the water metabolism probably rose in periods II and III. Creatinine increased significantly in III.<BR>(3) No significant variation of Na was observed but the total excretion including the sweat was to be much greater in periods II and III increasingly, and the difference of Ca and Mg between I and II was not significant, while total excretion significantly rose in III.<BR>(4) The Na/K ratios fell in periods II and III. The fall seems to be caused by promotion in K excretion and in Na retention relatively, in which the rise of the function of the adrenal cortex is suggested.<BR>[B] Serum contents of Na, K, P, Ca and Mg in the three different periods.<BR>The fall of Na in periods II and III was significantly greater, in which the effect of the sweat excretion is considered, while K rose significantly in the same periods. The increase of P was in II and III. Both Ca and Mg showed a tendency to increase in III.<BR>[C] Diurnal pattern of the urinary excretions in the three different periods.<BR>(1) The increase of the urine excretion was showen with about 2 hours lag after the morning exercise and the increase pattern by the afternoon and evening exercises were also shown. Two peak pattern of creatinine in period II was similar to that of the urine volume.<BR>(2) Increase patterns of Na, K, Ca and Mg excretion in periods II and III were also observed with the physical exercise. In the morning exercise the increase appeared 2 hours after the exercise, though in the afternoon and the evening exercises the increase appeared from the time of exercise. The pattern of Na and K showed that the increase after the morning exercise was greater than that by the afternoon and the evening exercises. The variation pattern of Ca and Mg showed that the time lag in the increase existed in comparison with that of Na and K, in which the greater increase by the afternoon and the evening exercises was observed noticeably compared with that of the morning.<BR>(3) Regarding to P excretion, the decrease during the daytime, and the increase in the sleeping time was common through the three periods. The increase in the evening by the evening exercise in periods II and III was remarkable.