Hematuria and microalbuminuria after a 100 kilometer race.

An investigation into hematuria and microalbuminuria induced by prolonged physical exercise was carried out by studying 26 runners who took part in a 100 km race by collecting urine samples before, after the race, and 24 hours later. Microscopic hematuria was present in two runners before the race. After this strenuous exercise there was macroscopic hematuria in five runners (19.2%) and microscopic hematuria in nine (34.6%). On examination by phase contrast microscopy there were neither dysmorphic erythrocytes nor red cell casts. Albuminuria was measured by radial immunodiffusion and was expressed as Ualb/Ucreat and Ualb/Uosm ratios. Clinical albuminuria was found in five runners with macroscopic hematuria, and microalbuminuria in 13 of the 21 remainders; in 6 of them it was associated with microscopic hematuria. Twenty-four hours later all of the results were normal with the exception of the five runners who have had macroscopic hematuria and another one with microalbuminuria without hematuria. We conclude that determination of albumin excretion in runners after exercise should be made as well as hematuria, and particular attention should be paid to cases of severe and/or prolonged microalbuminuria, since such individuals may be at risk of renal disease.