Effect of a carbohydrate-electrolyte drink on endurance capacity during prolonged intermittent high intensity running.
OBJECTIVE
To examine the effect of a carbohydrate-electrolyte solution on endurance capacity during prolonged intermittent running.


METHODS
Nine subjects (eight men and one woman) ran to exhaustion on a motorised treadmill on two occasions separated by at least 10 days. After an overnight fast, they performed repeated 15 second bouts of fast running (at 80% Vo2MAX for the first 60 minutes, at 85% Vo2MAX from 60 to 100 minutes of exercise, and finally at 90% Vo2MAX from 100 minutes of exercise until exhaustion), separated by 10 seconds of slow running (at 45% Vo2MAX). On each occasion they drank either a water placebo (P) or a 6.9% carbohydrate-electrolyte (CHO) solution immediately before the run (3 ml/kg body mass) and every 20 minutes thereafter (2 ml/kg body mass).


RESULTS
Performance times were not different between the two trials (112.5 (23.3) and 110.2 (21.4) min for the P and CHO trials respectively; mean (SD)). Blood glucose concentration was higher in the CHO trial only at 40 minutes of exercise (4.5 (0.6) v 3.9 (0.3) mmol/1 for the CHO and P trials respectively; p < 0.05), but there was no difference in the total carbohydrate oxidation rates between trials.


CONCLUSIONS
These results suggest that drinking a 6.9% carbohydrate-electrolyte solution during repeated bouts of submaximal intermittent high intensity running does not delay the onset of fatigue.
Nassis
G P
GP
Department of Physical Education, Sports Science, and Recreation Management, Loughborough University, United Kingdom.
Williams
C
C
Chisnall
P
P
D000328:Adult; D001628:Beverages; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition; D004040:Dietary Carbohydrates / Q000008:administration & dosage* / Q000378:metabolism; D004311:Double-Blind Method; D004326:Drinking; D004573:Electrolytes / Q000008:administration & dosage* / Q000378:metabolism; D005080:Exercise Test; D017079:Exercise Tolerance / Q000502:physiology*; D005215:Fasting; D005221:Fatigue / Q000503:physiopathology; D005260:Female; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000502:physiology; D010465:Perception; D010807:Physical Endurance / Q000502:physiology*; D010919:Placebos; D012420:Running / Q000502:physiology*; D013546:Sweating / Q000502:physiology; D013997:Time Factors; D014867:Water / Q000008:administration & dosage
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D004573:Electrolytes; D007773:Lactates; D010919:Placebos; D014867:Water