Abstract

The purpose of the study was to examine the excretion of sodium, potassium, calcium, magnesium and phosphorus in urine of top cyclists given a mineral deficient diet during multistage bicycle races. The cyclists took part in two- and three-stage races (total: 330 and 412 km, respectively) and in the Peace Bicycle Race (total: 1670 km). It was shown that after finishing every race the excrection of Na, K and Mg was within reference values, and excretion of P a little above the upper limit. Excretion of Ca after finishing the two- and three-stage races was above reference values, and after finishing PBR, the level of this element in urine was substantially reduced (hypocalciuria). It is supposed that increased excretion of Ca could be associated with reduced resorption of this element in the kidney. Excessive losses of Ca during PBR brought about hypocalciuria, probably as the result of initiation of the protective processes in the body. It seems, that due to losses of Ca and other electrolytes during multistage bicycle races, the cyclists should be supplemented with mineral preparations, especially in cases of their insufficient supply in the diet. Verf.-Referat