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The Physical Working Capacity of Healthy Children: Seasonal Variations and Effect of Ultraviolet Irradiation and Vitamin‐D Supply
Author(s) -
BERVEN HANS
Publication year - 1963
Publication title -
acta pædiatrica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 115
eISSN - 1651-2227
pISSN - 0803-5253
DOI - 10.1111/j.1651-2227.1963.tb16184.x
Subject(s) - medicine , hemoglobin , statistical significance , zoology , vitamin , physiology , surgery , biology
Two groups, each consisting of about 30 children aged 10–11 years, were investigated with regard to physical working capacity, PCW 10–11 and itsannual variations. One of these groups, the test group, received vitamin D on two occasions: on the one hand, a daily dose of 1500 I.U. administered continuously for a period of two months; and on the other, a single massive dose of 400,000 I.U. The effect of vitamin D on PWC which had previously been reported by several authors could not be shown to be of statistical significance. The other group, the control group, like the test group, was subject to seasonal variations in PWC, with a significant minimum in late autumn, November December, and a maximum in April‐May. The cause of the observed seasonal variations have been discussed, and it seems that, to a great extent, they were due to variations in physical activity on account of differences in climate and in the length of daylight during the year. In a smaller group the effect was studied of UV irradiation on PWC, heart volume, blood volume and total hemoglobin, in comparison with those of a control group. No effect of UV irradiation which was of statistical sig nificance was observed in connection with the test group. With regard to PWC and heart volume, both groups showed similar seasonal variations as those found in the larger material. In connection with blood volume and total hemoglobin, a somewhat divergent course was noted, as they increased during the entire period of investigation. The increase was, however, slightly larger during the spring months in comparison with that which was observed during the period October‐December and consequently, it appears that also these parameters were subject to some seasonal variations.