Correlation between Pre and Post Exercise Blood Lactate and pH

Abstract

Background: The body’s response to strenuous activity can be observed by subjecting it to exercise. During exercise lactic acid is produced in the skeletal muscles leading to decline in intracellular pH. Other anions and sodium/hydrogen exchange could also account for acidosis. The aim of this study was to observe the effect of intensity and duration of exercise on blood lactate and pH.

Material & Methods: This study was conducted in Department of Physiology, Basic Medical Sciences Institute, Jinnah Postgraduate Medical Centre, Karachi. Thirty male, adult subjects were selected and divided into two groups. Subjects of each group were exercised on treadmill. Group-I subjects performed exercise by running for 2-3 minutes at 7% grade and speed of Km/hour and Group-II subjects performed exercise by walking for 7-10 minutes, at zero grade and speed of 5-6 Km/hour. Pre and post exercise blood samples were taken for lactate and pH estimation.

Results: Increase in blood lactate after exercise was more in Group-I subjects (43.197%, p<0.001) than Group-II (27.273%, p<0.001). Blood pH decreased significantly after exercise by 100% in both groups (p<0.001). In Group-I the correlation between post-exercise blood lactate and pH was negligible (r=0.140, p>0.5) while in Group-II a week degree of correlation was found (r=0.317, p<0.5).

Conclusion: The magnitude of post-exercise changes in blood lactate and pH depend upon the intensity and duration of exercise but correlation between post-exercise blood lactate and pH is weak and nonsignificant.