The incidence of exercise-induced hematuria is reported to be between 5% and 25% and available literature suggests that it lasts for a few hours to a maximum of 3 days. We analyzed the urine sediment of healthy participants between the age of 20 and 50 years before and after a 5 km run. Anyone with abnormal pre-exercise sediment was excluded from the study. Of 491 participants, 59 (12%) developed post exercise hematuria when the run had to be completed in allotted time. However, when the run was completed without time limit, only 1.3% (4 of 316) developed hematuria (p < 0.001). We found that the younger participants (age < 30 years) had a significantly higher incidence of hematuria as compared to their older compatriots (p = 0.019). The mean duration of hematuria was 1.98 ± 1.89 days and 81% of the participants cleared their hematuria within 3 days. In 12% it lasted between 3 and 7 days and in 7% it continued beyond 7 days. Three individuals had persistence of hematuria beyond day 14 and all these were found to have primary glomerular disease on renal biopsy [two had IgA nephropathy and one focal segmental glomerulosclerosis (FSGS)]. We conclude that exercise-induced hematuria can last up to a fortnight. However, if it persists beyond a fortnight, it is unlikely to be functional and an underlying cause is likely. Hematuria following exercise seems to be related to the intensity of effort during exercise rather than its duration.
Keywords: Exercise; hematuria.