A slight acidity depresses oxidation, and increasing alkalinity, even to a marked degree, greatly increases the rate of oxidation. The work of Warburg, McClendon and Mitchell showed that in general an increase in hydroxyl ion concentration increased the oxygen consumption. Consumption of oxygen in the tissues increases with increasing pH.
The pH of our blood is very tightly buffered thanks to the bicarbonate it contains and to hemoglobin. That's why the pH of our blood stays within a narrow range. Since our cells release carbon dioxide as they break down sugars, however, the carbon dioxide and carbonic acid concentration is higher in blood flowing through your tissues than blood in your lungs, where it is relatively carbon dioxide–poor. Consequently, the pH of blood in the lungs stays fairly constant at around 7.6, while the pH of blood in the tissues is closer to 7.2. This slight difference in pH has important ramifications.
 THE EFFECT OF pH ON THE OXYGEN CONSUMPTION OF TISSUES. Huntington Memorial Hospital Harvard University. (Received for publication, May 15, 1925.)