Foot strike hemolysis, also known as exercise-induced hemolysis, occurs due to the destruction of erythrocytes in the capillaries of the foot due to repetitive contact with the ground.
Foot strike hemolysis, also known as exercise-induced hemolysis, occurs due to the destruction of erythrocytes in the capillaries of the foot due to repetitive contact with the ground. This process was first identified in 1881 when a German soldier was found to have multiple episodes of hemoglobinuria after marching. There are other theories as to why athletes develop an intravascular hemolysis and develop what is called “sports anemia”.
One process is that repetitive large muscle contractions can cause destruction of red blood cells and cause an anemia. Another cause of a sports anemia is the development of a hemodilution anemia secondary to an increase in plasma volume with exercise. Increased levels of hemolysis have been found in runners compared to swimmers and cyclists, suggesting foot strike hemolysis as the primary source of exercise-induced hemolysis.
Potential paraphysiological mechanisms involved in exercise-induced hemolysis. Foot strike hemolysis can be diagnosed with serum lab findings that occur during and after exercise. Hemolysis of the erythrocytes will cause hemoglobin and iron to be released.
Haptoglobin is an acute phase reactant whose job is to bind to free hemoglobin. During hemolysis free hemoglobin is released and the haptoglobin levels are decreased due to their binding with hemoglobin. Elevated MCV levels can also be seen because of the selective destruction of older RBCs.
A urinalysis may also show a hemoglobinuria due to the intra-vascular release of hemoglobin during the destruction of the erythrocyte. Another level that can be elevated with hemolysis is lactate dehydrogenase, which has been found to be elevated with foot strike hemolysis. Finally, elevated unconjugated bilirubin levels can be seen due to the destruction of hemoglobin.
If you are experiencing symptoms that may be related to foot-strike hemolysis, it is important to see a sports medicine physician. Early evaluation and treatment typically lead to better outcomes. Do not ignore pain or symptoms that are limiting your activity.
*This article is for educational purposes only and does not substitute for professional medical advice. Always consult a qualified healthcare provider.*
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