KOISTINEN, P. O., H. RUSKO, K. IRJALA, A. RAJAMÄKI, K. PENTTINEN, V-P. SARPARANTA, J. KARPAKKA, and J. LEPPÄLUOTO. EPO, red cells, and serum transferrin receptor in continuous and intermittent hypoxia. Med. Sci. Sports Exerc., Vol. 32, No. 4, pp. 800–804, 2000.
Erythropoietic response in 10 healthy nonsmoking volunteers exposed to normobaric hypoxia continuously or intermittently 12 h daily for 7 d was evaluated in a randomized cross-over study.
An oxygen content of 15.4% corresponding to an altitude of 2500 m was created by adding nitrogen into room air in a flat. Venous blood samples for hemoglobin (Hb), hematocrit (Hct), reticulocytes, serum erythropoietin (S-EPO), red cell 2,3-diphosphoglycerate (2,3-DPG), serum ferritin (S-Ferrit), and serum soluble transferrin receptor (S-TransfR) were drawn at 8:00 a.m.
S-EPO was increased from baseline values of 22.9 ± 9.6 and 20.5 ± 10.1 U·L−1 to 40.7 ± 12.9 (P < 0.05) and 35 ± 14.3 U·L−1 (P < 0.05) after the first night in continuous and intermittent hypoxia, respectively, and remained elevated throughout both exposures. Hb and Hct values did not show any significant changes. Red cell 2,3-DPG rose from baseline a value of 5.0 ± 0.8 to 5.9 ± 0.7 mmol·L−1 (P < 0.05) after the first day in continuous hypoxia and from 5.2 ± 0.7 mmol·L−1 to 6.1 ± 0.5 mmol·L−1 on day 3 (P < 0.05) during intermittent hypoxia. The reticulocyte count rose significantly (P < 0.05) after 5 d in both experiments. S-transferrin receptor level rose significantly from 2.2 ± 0.4 and 2.1 ± 0.5 mg·L−1 to 2.6 ± 0.5 mg·L−1 and 2.3 ± 0.6 mg·L−1 on day 5 (P < 0.05), to 2.7 ± 0.5 mg·L−1 and 2.5 ± 0.6 mg·L−1 on day 7 (P < 0.05) under continuous and intermittent hypoxia, respectively.
We suggest that intermittent exposure to moderate normobaric hypoxia 12 h daily for 1 wk induces a similar stimulation of erythropoiesis as continuous exposure.
Health Center Hospital of Oulu, FINLAND; Research Institute for Olympic Sports, Jyväskylä, FINLAND; Department of Clinical Chemistry and Hematology, University of Turku, FINLAND; and Vuokatti Sports and Training Center, FINLAND; Department of Sports Medicine, Deaconess Institute, Oulu, FINLAND; Kainuu Central Hospital, Kajaani, FINLAND; and Department of Physiology, University of Oulu, FINLAND
Submitted for publication August 1997.
Accepted for publication August 1998.
Address for correspondence: Dr. Pentti Koistinen, Health Center Hospital of Oulu, Box 8, SF-90015 Oulu, Finland; E-mail: Pentti.Koistinen@ouka.fi.