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Biochemical adaptation to environmental hypoxia

Chapter 8 explores mechanisms of hemoglobin adaptation to environmental hypoxia. Vertebrates living in hypoxic environments face the physiological challenge of optimizing the trade-off between oxygen loading at the respiratory surfaces and oxygen unloading in the tissue capillaries. In air-breathing and water-breathing vertebrates alike, fine-tuned adjustments in hemoglobin-oxygen affinity provide an energetically efficient means of compensating for a reduced oxygen tension of arterial blood. The adaptive significance of such changes is indicated by evolved changes in hemoglobin function in high-altitude mammals and birds, and erythrocytic acclimatization responses to environmental hypoxia in teleost fishes. An important goal for future research is to elucidate the specific physiological mechanisms by which changes in the oxygenation properties of hemoglobin translate into enhancements of whole-animal aerobic performance.