Arterial Oxygen Tension in Relation to Age in Healthy Subjects

Abstract

Arterial O2 tension was determined with the polarographic technique in 152 normal subjects of progressively increasing age (14-84 yr). A constant and progressive decrease of PaO2 [arterial O2 pressurel values with increasing age was found. The difference between the PaO2 mean values of the extreme age groups is of 20 mm Hg. A regression equation relating PaO2 to age was calculated. An increased inequality of the V/Q [ventilation/perfu-sionl ratio is likely to be responsible for an increased A-a [Alveolar-arterial ] O2 tension difference and for a decline of PaO2 with in-creasing age. The restrictive normality criteria adopted, the provenience of the subjects from an agricultural area and the exclusion of smokers allow to attribute to aging only the observed decrease of PaO2 witn age.