title: Time course of the hemoglobin mass response to natural altitude training in elite endurance cyclists.
abstract: To determine the time course of hemoglobin mass (Hb(mass)) to natural altitude training, Hb(mass), erythropoietin [EPO], reticulocytes, ferritin and soluble transferrin receptor (sTfR) were measured in 13 elite cyclists during, and 10 days after, 3 weeks of sea level (n=5) or altitude (n=8, 2760 m) training. Mean Hb(mass), with a typical error of ∼2%, increased during the first 11 days at altitude (mean ± standard deviation 2.9 ± 2.0%) and was 3.5 ± 2.5% higher than baseline after 19 days. [EPO] increased 64.2 ± 18.8% after 2 nights at altitude but was not different from baseline after 12 nights. Hb(mass) and [EPO] 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%), sTfR was elevated at Day 12 (18.9 ± 15.0%), but both returned to baseline by Day 20. Hb(mass) and [EPO] decreased on descent to sea level while ferritin increased. The mean increase in Hb(mass) observed after 11 days (∼300 h) of altitude training was beyond the measurement error and consitent with the mean increase after 300 h of simulated live high:train low altitude. Our results suggest that in elite cyclists, Hb(mass) increases progressively with 3 weeks of natural altitude exposure, with greater increases expected as exposure persists.
authors.affiliation: Department of Physiology, Australian Institute of Sport, Canberra, Australia. laura.garvican@ausport.gov.au
authors.forename: L
authors.initials: L
authors.lastname: Garvican
authors.forename: D
authors.initials: D
authors.lastname: Martin
authors.forename: M
authors.initials: M
authors.lastname: Quod
authors.forename: B
authors.initials: B
authors.lastname: Stephens
authors.forename: A
authors.initials: A
authors.lastname: Sassi
authors.forename: C
authors.initials: C
authors.lastname: Gore
mesh_terms: D000328:Adult; D000531:Altitude; D001642:Bicycling / Q000502:physiology*; D004906:Erythrocyte Count; D004921:Erythropoietin / Q000097:blood; D015444:Exercise / Q000502:physiology*; D005293:Ferritins / Q000097:blood; D006454:Hemoglobins / Q000378:metabolism*; D006801:Humans; D011990:Receptors, Transferrin / Q000097:blood; D012156:Reticulocytes; D013997:Time Factors; D055815:Young Adult
chemical_list: D006454:Hemoglobins; D011990:Receptors, Transferrin; D004921:Erythropoietin; D005293:Ferritins