A transient decrease in red blood cells and hemoglobin levels (grams per deciliter of blood).
A decrease in red cell volume from excessive red cell breakdown due to excessive physical activity.
Sports anemia is a condition that commonly occurs after beginning an exercise program. When initiating such a program, plasma volume typically expands, thereby diluting the concentration of red blood cells and hemoglobin in the blood. In some cases the expansion of plasma volume is sufficient to produces an apparent iron deficiency anemia. Although several studies have actually indicated that exercise training may lead to iron losses through sweat, hemolysis, and gastrointestinal bleeding, in most cases the apparent anemia is simply caused by fluid volume expansion in the blood vessels and is merely transient. Upon adaptation to training, the condition will disappear. For those athletes who have symptoms of anemia well after the initiation of training, consumption of foods rich in iron may be required. Normally menstruating female athletes are of particular concern for true iron deficiency due to monthly losses of iron through menstruation.