The effects of rehydration on cycling performance after exercise-induced dehydration.
The effects of 7.6% carbohydrate-electrolyte solution (CES) and placebos (P) on rehydration (R) after exercise-induced dehydration and on a subsequent time-trial (TT) of cycling performance were studied. Thirteen male subjects exercised in a thermally-controlled environment (28 degrees C, 63% RH) until 3% of their body weight was lost. After exercise, the subjects moved to a neutral environment (22 degrees C) and rested for 30 minutes prior to a 2-hour R period. During R, subjects were fed CES or P to a maximum volume of 120% of previous body mass loss at 0, 30, and 60 minutes, in bolus-doses of 50%, 40% and 30% respectively. After R, subjects performed a 1-hour TT with no further fluid intake. % R with CES was significantly higher than with P (70 +/- 3% vs 60 +/- 5%; p < 0.01). During the TT, blood glucose dropped in the CES group but not in the P group. It was found that, despite a more effective R with CES, the performance results did not differ between groups (65.1 +/- 2.2 minutes and 65.2 +/- 2.3 minutes for CES and P respectively). It is suggested that an insulin-mediated rebound effect on CHO metabolism during TT, in which no further CHO was supplied, nullified the benefits of rehydration.
Singh
R
R
Sports Science Unit, School of Medical Sciences, Universiti Sains Malaysia, Kelantan. rabindar@kck.usm.my
Brouns
F
F
Kovacs
E
E
D000328:Adult; D001628:Beverages / Q000032:analysis; D001642:Bicycling / Q000502:physiology*; D001786:Blood Glucose / Q000032:analysis; D003681:Dehydration / Q000209:etiology* / Q000628:therapy; D005440:Fluid Therapy; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D009426:Netherlands; D010919:Placebos
D001786:Blood Glucose; D007328:Insulin; D010919:Placebos