Abstract

This study monitors changes in urinary excretion of water and minerals before and after exercise in pre-menopausal women and in those using oral concentration. Resting urine flow rate was lower and sodium output significantly higher (p<0.02) during the normal post-menstrual phase than during other phases of the cycle. These changes were unrelated to glomerular filtration rate and might impede maximal performance. After exercise an oliguria and hyponatriuresis were most pronounced during the menstrual phase. In addition the resting urinary output of calcium and magnesium were unrelated to normal oestrogenic and progestegenic cyclic surges. A>mongst oral contraceptive users, resting excretion of water, minerals and creatinine were all significantly lower than general menstrual cycle values (p<0.01) and further reductions, in salts and water output occurred with exercise. Basal calcium and magnesium excretion rates were significantly lower than general menstrual cycle values (p<0.05). Renal conservation of water and salts for pill takers may affect renal homeostasis. The consequences of mineral retention are unknown. Verf.-Referat