Plasma biochemical changes and acid-base equilibrium changes in capillary blood nursing frequency repeated submaximal physical exercise in untrained subjects

Abstract

The reported investigations were carried out on healthy men aged 20--22 years in two groups: group A of 11 subjects and group B of 12 subjects. Both groups performed five times at 50-minute intervals submaximal physical exercise during 10 minutes on a Monark ergometer. Group A performed the exercise at a steady heart rate of about 170/min with variable workload, while group B performed it at a steady workload but changing heart rate. At rest and after each exercise the plasma concentrations of free fatty acids, glucose and amino-acid nitrogen were determined in both groups, and changes in the parameters of acid-base equilibrium were studied in capillary blood. It was found that after each consecutive exercise the concentration of free fatty acids (FFA) increased ever more and the rise of the haematocrit index decreased. Glucose concentration decreased after the 1st, 2nd and 3rd exercises, but increased after the remaining two exercises. The concentration of amino-acid nitrogen showed an increasing tendency after exercise in both groups. The changes in the acid-base equilibrium, that is its shifting towards metabolic acidosis were greatest after the first exercise. In group A each consecutive exercise caused less pronounced disturbances of acid-base equilibrium. In group B the intensity of metabolic acidosis was lower in consecutive exercises in relation to the first one, but it was greater than in group A.