A person actively engaged in exercise may develop a pseudoanemia due to plasma volume expansion that results in hemodilution and a fall in hemoglobin. It is a common explanation for apparent anemia in active athletes.


Changes in plasma volume associated with exercise:

(1) during exercise: contraction

(2) within a few hours after exercise: normalization

(3) afterwards: expansion



(1) mild normochromic normocytic anemia noticed several hours after exercise

(2) normal physical exam with no evidence of hemolysis, jaundice or hepatosplenomegaly

(3) normal serum iron, folate and vitamin B12

(4) no evidence of impaired performance

(5) exclusion of other causes of anemia

(6) normalization of hemoglobin within a week after discontinuation of an exercise program


The diagnosis of dilutional pseudoanemia:

(1) may co-exist with other types of anemia (mixed)

(2) would not explain a hemoglobin < 13 g/dL in a male or < 11.5 g/dL for a female


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