Runner's Anemia

Macrocytic anemia occurring in patients with fatigue suggests numerous diagnoses, ranging from nutritional deficiencies to a myelodysplastic syndrome. A careful history-taking is critically important for recognition of runner's anemia, which is due to plasma volume expansion, with hemolysis from the pounding of feet on pavement, and hemoglobinuria. Gastrointestinal blood loss may also contribute to anemia in long-distance runners. Early recognition of runner's anemia in patients with a complex presentation of anemia is important in circumventing many diagnostic tests. Runner's anemia should be considered when, amidst a constellation of signs and symptoms, mild anemia is well tolerated by an avid runner.