THE EFFECT OF PRE-EXERCISE GLUCOSE INGESTION ON THE OCCURRENCE OF METABOLIC ACIDOSIS WITH PROGRESSIVE GRADED EXERCISE STRESS

This study was conducted to determine the effects of pre-exercise glucose ingestion on the metabolic response to progressive graded exercise. Eight subjects completed two identical exercise bouts following ingestion of water and a glucose solution. Each exercise bout consisted of a walk-run protocol from rest to maximum exertion. Expired air was analyzed at thirty-second intervals utilizing an automated open circuit analysis system. Venous blood was collected from an antecubital vein, utilizing an indwelling teflon catheter and analyzed for plasma glucose (PG) and plasma lactic acid (PLA). The anaerobic threshold (AT) was defined as the occurrence of metabolic acidosis with progressive exercise, and determined by identifying the onset of an increase in PLA relative to oxygen uptake (VO(,2)).;It was concluded that pre-exercise glucose ingestion does not alter the anaerobic threshold point relative to VO(,2) with progressive graded exertion. It was also observed that the metabolic effects of glucose ingestion may vary considerably from subject to subject.;Polynomial regression analysis was conducted on the VO(,2) data to observe the trend development for the two test conditions. VO(,2) during progressive graded exercise following water ingestion followed a quadratic trend: VO(,2) = 11.65876 + (4.81066 (,*) stage) + (-0.10837 (,*) stage('2)). A quadratic trend was also observed for VO(,2) following glucose ingestion: VO(,2) = 11.89851 + (4.58965 (,*) stage) + (-0.09042 (,*) stage('2)). Maximal values for heart rate, VO(,2), respiratory exchange ratio, minute ventilation, PLA, and PG were not significantly different between test conditions. Anaerobic threshold occurred at 68.94% and 68.91% of maximal VO(,2) for the water and glucose tests respectively. The differences were not significant. Plasma glucose tended to remain near resting levels throughout the water test with an increasing trend at near-maximal exertion. During the glucose test two subjects tended to maintain elevated PG throughout the exercise bout, while the remaining six subjects exhibited a decreasing trend in PG.