DEVELOPMENT OF SPORTS ANEMIA IN PHYSICALLY FIT MEN AFTER DAILY SUSTAINED SUBMAXIMAL EXERCISE

Abstract

Hematological changes were studied in physically fit young soldiers who marched 35 km/day for 6 days, working at 35% of their VO2 max. Four days of marching produced decreases in numbers of erythrocytes (RBC) and in hematocrit (Hct). This sports anemia persisted beyond day 6 into the post-march period and was accompanied by decreases in Hb, mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC) and mean corpuscular volume (MCV). The latter decrease was attributed to a preferential destruction of large RBC. The post-march period was characterized by an early (2 days) recovery of RBC numbers, Hct and MCV, and a persistent (> 4 days) decrease in Hb, MCH and MCHC. This pattern, characteristic of hypochromic macrocystosis, possibly reflects a premature release of young RBC from the bone marrow. Sports anemia, previously reported to occur with intensive physical exercise, can also result from sustained and repetitive submaximal exercise.