BLOOD CHANGES HAPPEN QUICKLY ON EXPOSURE TO ALTITUDE AND THEN SHOW NO FURTHER ADAPTATIONS
Garvican, L. A., Martin, D. T., Clark, M. A., Quod, M., Stephens, B., Prommer, N., Schmidt, W. F., Impellizzeri, F. M., Rampinini, E., Sassi, A., & Gore, C. J. (2008). The time course of the erythropoietic response to natural altitude training in elite endurance cyclists. ACSM 55th Annual Meeting Indianapolis. Presentation Number, 738.
"Erythropoietin (EPO) induced increases in total hemoglobin mass (tHb) are generally thought to explain improvements in endurance performance following 3-4 weeks of altitude training. However, the time course of the total hemoglobin mass response to natural altitude in endurance athletes is not well documented".
This study identified when the greatest gains in total hemoglobin mass occur during 3 weeks of natural altitude training in elite endurance cyclists (N = 13). Total hemoglobin mass (CO re-breathing), erythropoietin reticulocytes, and soluble transferrin receptor were measured throughout 21 nights of structured training in competitive cyclists preparing for World Championships. An altitude group (N = 8) lived at 2,760 m and trained for 3-6 hours a day at 1,000-2,760m. A sea-level group (N = 5) lived and trained at ~600 m. All cyclists completed similar training (600-900 km per week; low intensity with frequent climbing 10,000-15,000 m per week). Duplicate measures for all dependent variables were performed at baseline. Daily iron supplementation (305 mg ferrous sulphate + 1,000mg Vitamin C) was administered for 1-2 weeks before and during the study.
During adaptation, total hemoglobin mass increased from baseline in the altitude group. There was no change in the sea-level group. Erythropoietin increased markedly by day 2 but returned to baseline levels by day 12 in the altitude group. Erythropoietin did not change in the sea-level group. Reticulocytes increased slightly by day 5 but were no different to baseline by day 20 in the altitude group. Soluble transferrin receptor was higher at day 12 but no different to baseline by day 20 in the altitude group. For the sea-level group, soluble transferrin receptor was elevated only at day 21.
Implication. Total hemoglobin mass increased over the first 11 days of altitude training/adaptation. It did not noticeably increase with additional altitude exposure. Erythropoietin increased and then subsided to pre-adaptation levels within 12 days. After 12 days, total hemoglobin mass, erythropoietin, and soluble transferrin show no beneficial change in altitude adaptation.
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