HEMOGLOBIN MASS INCREASES WITH ALTITUDE EXPOSURE
Garvican, L., Martin, D., Quod, M., Stephens, B., Sassi, A., & Gore, C. (2012). Time course of the hemoglobin mass response to natural altitude training in elite endurance cyclists. Scandinavian Journal of Medicine & Science in Sports, 22, 95-103.
This study determined the time course of hemoglobin mass to natural altitude training. Hemoglobin mass, erythropoietin, reticulocytes, ferritin, and soluble transferrin receptor were measured in elite cyclists (N = 13) during, and 10 days after three weeks of sea level (N = 5) or altitude (N = 8; 2,760 m) training.
Mean hemoglobin mass, with a typical error of ~2%, increased during the first 11 days at altitude and was 3.5±2.5% higher than baseline after 19 days. Erythropoietin increased 64.2±18.8% after two nights at altitude but was not different from baseline after 12 nights. Hemoglobin mass and erythropoietin did not increase in sea level. Reticulocytes were slightly elevated in altitude at Days 5 and 12 (18.9±17.7% and 20.4±25.3%), soluble transferrin receptor was elevated at Day 12 (18.9±15.0%), but both returned to baseline by Day 20. Hemoglobin mass and erythropoietin decreased on descent to sea level while ferritin increased. The mean increase in hemoglobin mass observed after 11 days (~300 hours) of altitude training was beyond the measurement error and consistent with the mean increase after 300 hours of simulated live-high:train-low altitude.
Implication. In elite cyclists, hemoglobin mass increases progressively over three weeks of natural altitude exposure. Some blood factors (e.g., reticulocytes, soluble transferring receptor) initially react to altitude exposure but then return to sea-level values.
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