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Bioenergetics of adaptation to the environmental hypoxia of high altitude at rest and exercise
Author(s) -
Reynafarje Baltazar Davila
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.972.4
Subject(s) - bioenergetics , mitochondrion , hypoxia (environmental) , transduction (biophysics) , effects of high altitude on humans , biophysics , chemistry , altitude (triangle) , oxidative phosphorylation , oxygen , biology , biochemistry , microbiology and biotechnology , anatomy , geometry , mathematics , organic chemistry
The effect of hypoxia on the mechanism of energy transduction has been studied by determining the rates of O2 uptake and energy generation in both humans and guinea‐pig mitochondria under resting and active metabolic conditions. The following findings were made. 1) The O2 level required for half maximal rates of ATP syntesis (Km for O2)is higher than 0.03 mM or 20 torr. 2)The so‐called lactate paradox of high altitude adaptation is no more than an improved efficiency in the mitochondrial process of energy transduction. 3)The amount of ATP formed or energy generated per atom of O2 consumed by guinea‐pig mitochondria or humans during strenuous physical exercise is significantly higher in natives to high altitude than in those from sea level. 4) The mitochondrial rates of ATP synthesis are orders of magnitude higher than under state‐3 metabolic conditions provided the membrane is fully reduced, a conditions that is optimally attained during short periods of maximal hypoxia. It is concluded that athletes improve the reduced state of their muscles by enhancing the hypoxia during the warm up period, and that the most important factor in determining the extent and rates of energy transduction an ATP syntheis is not the proton gradient or the level of ADP but the level of O2 and the conformational state of the mitochondria