The Concentration of Blood Lactic Acid in Man during Muscular Work in Relation to the Partial Pressure of Oxygen of the Inspired Air.

Summary. The concentration of blood lactic acid was studied in subjects working on a bicycle ergometer and breathing nitrogen‐oxygen mixtures with a varying percentage of oxygen, with special reference to the conditions when the work had been continued long enough to ensure the reaching of a steady state of blood lactic acid. The rise from the rest value to the steady state value was found to have a certain inverse proportional relation to the partial pressure of oxygen of the inspired gas mixture. The causes of this fact, and of the effect of acclimatisation on blood lactic acid levels during work as investigated by E dwards , are discussed.