Relationship Between Level of Physical Condition and pH of Antecubital Venous Blood

¹ From the Physical Fitness Research Laboratory, University of Illinois, Urbana, Illinois

The ph of antecubital venous blood was measured in a group of 34 adult men and serially in two individuals during progressive training programs. The ph was correlated with the level of physical condition as determined by the time of a run to exhaustion on a motor driven treadmill. Modified techniques were incorporated in the use of the Beckman Glass Electrode ph Meter (Model G). Low correlations were found in the group study between the treadmill run time and both the postexercise ph and the decrease in ph during exercise. In contrast, high correlations were found in the individual subjects, measured serially, indicating relatively high levels of interdependence between the variables. The results obtained lead to the following conclusions: a) verification of earlier reports that a drop in ph occurs during exercise, b) drop in ph does not reflect the intensity of work in a group of individuals, c) ph reactions correlate quite well with the duration of severe exercise in a single subject, d) decrease in ph is a slightly better measure of stress than postexercise ph, e) physical training programs increase individual tolerance for stress, f) trained athletes are able to perform a given task at a lower level of stress (higher ph) in an exhaustive exercise.