Haematuria following a marathon run: source and significance.

Urine specimens were obtained from 98 runners before and immediately after running a half (21 km) or full (42 km) marathon. Specimens were examined for the presence of proteinuria, haematuria and whether the erythrocytes were normomorphic or dysmorphic as determined by phase contrast microscopy. Proteinuria occurred in 35% of those running the half and 69% running the full marathon. Haematuria with or without proteinuria occurred in 21% running the half and 22% running the full marathon. In runners with haematuria, dysmorphic erythrocytes were found in 30% of the half and 81% of the full marathon group. No urinary abnormalities were found on repeat examination 4 to 12 weeks after the run. These results suggest that non-glomerular bleeding, possibly from bladder contusions, predominates at shorter distances. With greater distances glomerular bleeding occurs. These abnormalities disappear with rest and do not appear to signify underlying urinary tract disease.