Consequences of 6 weeks of strength training on red cell O2 transport and iron status

Abstract

Effects of endurance training on O2 transport and on iron status are well documented in the literature. Only a few data are available concerning the consequences of strenuous anaerobic muscular exercise on red cell function. This study was performed to test the influence of strength training alone on parameters of red cell O2 transport and iron status. Twelve healthy untrained males participated in a strength-training programme of 2-h sessions four times a week lasting 6 weeks. After 6 weeks a small but significant reduction of haemoglobin (Hb; -5.4 g.l-1) was found (p less than 0.05). Mean red cell volume did not change, but a pronounced decrease of mean cell Hb concentration (from 329.2 g.l-1, SE 2.5 to 309.8 g.l-1, SE 1.2; p less than 0.001) and mean corpuscular Hb (from 29.6 pg, SE 0.4 to 27.7 pg, SE 0.3; p less than 0.01) was observed. Serum ferritin decreased significantly by 35% (p less than 0.01); transferrin, serum iron and iron saturation of transferrin were unaltered. Serum haptoglobin concentration was diminished significantly by 30.5% (p less than 0.01). The reticulocyte count had already increased after 3 weeks of training (p less than 0.05) and remained elevated during the following weeks. Strength training had no significant influence on the O2 partial pressure at which Hb under standard conditions was 50% saturated, red cell 2,3-diphosphoglycerate and ATP concentration as well as on erythrocytic glutamate-oxalacetate transaminase activity. The data demonstrate that mechanical stress of red cells due to the activation of large muscle masses led to increased intravascular haemolysis, accompanied by a slightly elevated erythropoiesis, which had no detectable influence on Hb-O2 affinity. Training caused an initial depletion of body iron stores (prelatent iron deficiency). Although Hb had decreased by the end of the training phase a true "sports anaemia" could not be detected.