EFFECTS OF PRE-EXERCISE FEEDINGS ON ENDURANCE PERFORMANCE

  • 1 January 1979
    • journal article
    • research article
    • Vol. 11  (1) , 1-5
Abstract
Male (8) and 8 female students were studied during exercise to exhaustion on a bicycle ergometer at 80 and 100% of .ovrhdot.VO2 max [maximal O2 uptake] following the ingestion of water (W), 75 g of glucose (G) or a liquid meal (M) (10 g protein, 12.5 g fat, 15 g CHO [carbohydrate]). When compared to the endurance ride (80% .ovrhdot.VO2 max) in the W treatment, endurance performance time was reduced by 19%, (P < 0.05) (53.2-43.2 min) as a result of the pre-exercise glucose feeding (trial G). No difference in performanance at 80% .ovrhdot.VO2 max was found between the W and M trials. The pre-exercise feedings had no effect on exercise time to exhaustion at 100% .ovrhdot.VO2 max. During the G and M trials at 80% .ovrhdot.VO2 max, most of the subjects demonstrated a transient decline in serum glucose (< 3.5 mM). After 30-40 min of exercise serum glucose returned to normal and was seldom low at the time of exhaustion. Serum free fatty acids (FFA) were depressed throughout the G trial. Impaired lipid mobilization following CHO ingestion was indicated. Glucose feedings 30-45 min before endurance exercise apparently increase the rate of CHO oxidation and impede the mobilization of FFA, thereby reducing exercise time to exhaustion.

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