The ABC of hypoxia – what is the norm

Authors

DOI:

https://doi.org/10.26124/bec:2022-0012.v2

Keywords:

ambient, anoxia, critical O2 pressure pc, functional hypoxia, hyperoxia, hypoxia, limiting O2 pressure pl, normoxia, oxygen O2, O2 concentration cO2 [µM], partial O2 pressure pO2 [kPa]

Summary

Hypoxia is a condition of oxygen levels below normoxia and opposite to hyperoxia. We here define the normoxic reference state by three complementary precepts: (A) ambient normoxia at sea level in the contemporary atmosphere and corresponding dissolved O2 concentrations at air saturation of aqueous environments; (B) biological compartmental O2 levels at ambient normoxia under physiological activity of healthy organisms in the absence of environmental stress (e.g. stress in a diving human, a stranded whale, a thermally stressed fish); and (C) O2 levels above the respiratory oxygen control region. In the oxygen control region, the capacity for O2 consumption is compromised by hypoxic partial O2 pressure as evaluated by O2 kinetics of respiration or other critical functions. The ABC of hypoxia distinguishes deviations from these reference points caused by different mechanisms: (∆A) ambient alterations of oxygen levels; (∆B) biological O2 demand exceeding O2 supply under pathological or experimental limitations of convective O2 transport or O2 diffusion; and (∆C) critical oxygen pressure in oxygen kinetics shifted by pathological and toxicological effects or environmental stress. The ABC of hypoxia may be of help in the design and interpretation of in vitro and in vivo experimental studies.

Cite:

Donnelly C, Schmitt S, Cecatto C, Cardoso LHD, Komlódi T, Place N, Kayser B, Gnaiger E (2022) The ABC of hypoxia – what is the norm. Bioenerg Commun 2022.12.v2. https://doi.org/10.26124/bec:2022-0012.v2

Published

2022-12-22

Issue

Section

Living Communications