Hematologic disorders

[Extract] At a global level, iron-deficiency anemia is the most commonly occurring nutritional deficiency. In developing countries or among high-risk groups, iron deficiency can affect 30%-40% of the population, whereas the prevalence of iron-deficiency anemia in the general community is typically 1%-3%. Recently, athletes have come under scrutiny as one such high-risk group. During the 1980s, exercise scientists commented on some interesting differences in the hematologic characteristics of long-distance runners. Endurance athletes were seen to have reduced plasma hemoglobin concentrations, a characteristic that seemed unfavorable for the performance of events reliant on the delivery of oxygen to working muscles (1). After study, this phenomenon was found to be a dilutional anemia, resulting from the increase in plasma volume that accompanies aerobic training (2). It is not considered to be a pathologic state and is not disadvantageous to performance, does not limit the production of red blood cells, and does not respond to iron-supplementation therapy (3).