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The effects of glucose polymer beverage ingestion during prolonged outdoor exercise in the heat
- Source :
- Scopus-Elsevier
-
Abstract
- The aim of this study was to examine the effect of ingestion of a glucose polymer drink on fluid and metabolic balance during a 30 km outdoor march in the heat (ambient temperature, 26-31 degrees C; relative humidity, 53-34%). The subjects were randomly assigned to one of three groups: 7.2% glucose polymer-electrolyte beverage (GP) (N = 16), flavored sweetened placebo drink (SP) (N = 15), and tap water (TW) (N = 18). The subjects in the three groups consumed similar volumes of fluid, and no differences were found in sweat rate and percent dehydration. Changes in plasma volume were smaller, though not statistically significant, for GP than for SP and TW (-2.8%, -5.4%, -9.4%, respectively). Changes in sodium concentrations and serum osmolality were similar in the three groups. Subjects consuming GP maintained during exercise a significantly higher (P less than 0.001) blood glucose concentration (range: 6.5-7.4 mmol.l-1) than the SP and TW groups. They were also found to have increased levels of serum insulin (29.3 +/- 18.5 mU.l-1) and no change in serum free fatty acids (0.52 +/- 0.19 mmol.l-1). In contrast, subjects ingesting SP or TW had significantly elevated (P less than 0.001) concentrations of free fatty acids (range: 1.35-1.74 mmol.l-1) compared with subjects consuming GP (0.35-0.52 mmol.l-1), with no significant change in blood glucose and serum insulin levels over the exercise period. We conclude that highly trained endurance athletes may maintain a higher blood glucose level by consuming GP during prolonged exercise in the heat without impairing fluid replacement.
- Subjects :
- Adult
Blood Glucose
Male
medicine.medical_specialty
Hot Temperature
Polymers
medicine.medical_treatment
Sodium
chemistry.chemical_element
Physical Therapy, Sports Therapy and Rehabilitation
Physical exercise
Placebo
Beverages
Internal medicine
medicine
Humans
Insulin
Ingestion
Orthopedics and Sports Medicine
Dehydration
Exercise
Fatty Acids
Osmolar Concentration
Water
Metabolism
Carbohydrate
medicine.disease
Glucose
Endocrinology
chemistry
Rehydration Solutions
Fluid replacement
Subjects
Details
- Database :
- OpenAIRE
- Journal :
- Scopus-Elsevier
- Accession number :
- edsair.doi.dedup.....b4902b0a80126bf67b07b896459768db