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Acute normobaric hyperoxia transiently attenuates plasma erythropoietin concentration in healthy males: evidence against the ‘normobaric oxygen paradox’ theory
Author(s) -
Keramidas M. E.,
Kounalakis S. N.,
Debevec T.,
Norman B.,
Gustafsson T.,
Eiken O.,
Mekjavic I. B.
Publication year - 2011
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/j.1748-1716.2011.02262.x
Subject(s) - erythropoietin , hyperoxia , medicine , endocrinology , oxygen , room air distribution , zoology , chemistry , anesthesia , biology , lung , organic chemistry , physics , thermodynamics
Aim: The purpose of the present study was to evaluate the ‘normobaric oxygen paradox’ theory by investigating the effect of a 2‐h normobaric O 2 exposure on the concentration of plasma erythropoietin (EPO). Methods: Ten healthy males were studied twice in a single‐blinded counterbalanced crossover study protocol. On one occasion they breathed air (NOR) and on the other 100% normobaric O 2 (HYPER). Blood samples were collected Pre, Mid and Post exposure; and thereafter, 3, 5, 8, 24, 32, 48, 72 and 96 h, and 1 and 2 weeks after the exposure to determine EPO concentration. Results: The concentration of plasma erythropoietin increased markedly 8 and 32 h after the NOR exposure (approx. 58% and approx. 52%, respectively, P ≤ 0.05) as a consequence of its natural diurnal variation. Conversely, the O 2 breathing was followed by approx. 36% decrement of EPO 3 h after the exposure ( P ≤ 0.05). Moreover, EPO concentration was significantly lower in HYPER than in the NOR condition 3, 5 and 8 h after the breathing intervention ( P ≤ 0.05). Conclusion: In contrast to the ‘normobaric oxygen paradox’ theory, the present results indicate that a short period of normobaric O 2 breathing does not increase the EPO concentration in aerobically fit healthy males. Increased O 2 tension suppresses the EPO concentration 3 and 5 h after the exposure; thereafter EPO seems to change in a manner consistent with natural diurnal variation.