THE EFFECTS OF A COCONUT WATER BEVERAGE ON BLOOD GLUCOSE HOMEOSTASIS DURING PROLONGED AEROBIC EXERCISE

Peter J. Chomentowski 3rd, Joshua A. Alis, Rayanne K. Nguyen, Judith M. Lukaszuk, David A. Walker, Amanda J. Salacinski

Abstract

Consumption of a carbohydrate-electrolyte beverage during prolonged exercise has been shown to maintain plasma glucose levels in recreational and competitive athletes. In the last few years, however, alternatives such as coconut water beverages have drawn attention due to a desire for a natural beverage compared to a manufactured carbohydrate-electrolyte beverage. The purpose of this study was to examine the effects of a coconut water beverage on blood glucose during prolonged exercise. Eleven endurance trained males participated in a randomized double blind study. Each subject completed three 90-minute trials consisting of a treadmill run at 60-70% of their maximal oxygen uptake while consuming one of three beverages per trial (water, carbohydrate beverage, coconut water beverage). Every 15 minutes the subject consumed 12 ounces of the blinded beverage. Blood glucose was measured at baseline, 15 min, 30 min, 45 min, 60 min, 75 min, and 90 min of the treadmill run. There was a significant difference (p<.05) in blood glucose values between water and the coconut water beverage at 45 min, 60 min, 75 min, and 90 min time points. No significant difference was found for blood glucose values between the coconut water beverage and a carbohydrate-electrolyte beverage (p>.05). This study indicates that a natural coconut water beverage had a significant effect on blood glucose homeostasis during prolonged exercise compared to water alone.

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