GLOSSARY

Exercise-induced haematuria is the presence of blood or red blood cells in the urine after physical activity; it is usually benign and temporary, resolving within 24–72 hours. It occurs in both contact and non-contact sports.

Causes and Mechanisms

• Bladder trauma (“runner’s bladder”): repeated impact of the back wall of an empty bladder against its base during running, producing bruise-like lesions in the bladder.
• Reduced kidney blood flow: low oxygen and increased glomerular permeability.
• Direct blows: in boxing, rugby, football and martial arts.
• Foot-strike haemolysis: destruction of red blood cells in the soles of the feet when running on hard surfaces, causing haemoglobinuria (not true haematuria).
• Myoglobinuria: in rhabdomyolysis; a positive dipstick without red cells.

Prevention

Completely emptying the bladder before running is not recommended; having some urine in the bladder prevents its walls striking each other. Adequate hydration, well-cushioned shoes and running on softer surfaces also help.

Clinical Importance

Haematuria that persists after 72 hours of rest, is accompanied by pain, fever, casts or proteinuria, or occurs in an older person requires full investigation for stones, infection, glomerular disease and tumours.

Relevance to Sport

• Practical example: a 45-year-old runner who has had pink urine several times after long runs should not attribute it only to exercise; although exercise haematuria is common, at this age they should also be checked for bladder and kidney cancer, especially if they smoke.