Effect of temperature on arterial blood gas tensions and pH during exercise

Abstract

We measured arterial blood Po2, Pco2 and pH at rest and during a standard exercise test on a bicycle ergometer in ten normal subjects. In five we measured esophageal and five arterial blood temperature during the exercise and corrected the arterial blood values to the temperature at the time the samples were collected. We found an average rise in temperature of 1 C (range 0.2–1.6 C) during exercise lasting about 30 min at loads up to an average of 1,200 kg-m/min. At the highest load the average correction for PaOO2 was 5.6 mm Hg, for PaCOCO2 1.6 mm Hg and for pH 0.014 units. Our corrected values showed a fall in PaCOCO2 and pH and a rise in PaOO2 during severe exercise. These findings are compatible with the development of a metabolic acidosis during severe exercise and indicate that our subjects were not limited by diffusion across the alveolar-capillary membrane. metabolic acidosis; alveolar capillary membrane diffusion; hyperventilation; PaOO2 and PaCOCO2 in severe exercise Submitted on June 17, 1963