In brief:The pathogenesis of exercise- related hematuria is not clearly understood. This review shows that the most important factors are the degree of aerobic demand and the duration of exercise. Dehydration, age, and diet are also implicated. The authors propose a theory based on increased vascular resistance, cortical shunting, and spiral calicine vessels. They say the problem seems to be benign, because athletes have no increased incidence of renal disease. After the initial evaluation to rule out occult urologic pathology, recurrences do not require complete reevaluation if they are characteristic of the previous episodes and if the urine clears in 24 to 48 hours.