Multiple transportable carbohydrates enhance gastric emptying and fluid delivery.
This study compared the effects of ingesting water (WATER), an 8.6% glucose solution (GLU) and an 8.6% glucose+fructose solution (2:1 ratio, GLU+FRU) on gastric emptying (GE), fluid delivery, and markers of hydration status during moderate intensity exercise. Eight male subjects (age=24+/-2 years, weight=74.5+/-1.2 kg, VO2max=62.6+/-2.5 mL/kg/min) performed three 120 min cycling bouts at 61% VO2max. Subjects ingested GLU, GLU+FRU (both delivering 1.5 g/min carbohydrate), or WATER throughout exercise, ingesting 2.1 L. Serial dye dilution measurements of GE were made throughout exercise and subjects ingested 5.00 g of D2O and 150 mg of 13C-acetate at 60 min to obtain measures of fluid uptake and GE, respectively. GLU+FRU resulted in faster rates of deuterium accumulation, an earlier time to peak in the 13C enrichment of expired air and a faster rate of GE compared with GLU. GLU+FRU also attenuated the rise in heart rate that occurred in GLU and WATER and resulted in lower ratings of perceived exertion. There was a greater loss in body weight with GLU corrected for fluid intake. These data suggest that ingestion of a combined GLU+FRU solution increases GE and "fluid delivery" compared with a glucose only solution.
Jeukendrup
A E
AE
Human Performance Laboratory, Department of Exercise Metabolism, School of Sport and Exercise Sciences, The University of Birmingham, Edgbaston, Birmingham, UK. A.E.Jeukendrup@bham.ac.uk
Moseley
L
L
D000328:Adult; D001628:Beverages; D001944:Breath Tests; D002951:Citrates / Q000008:administration & dosage; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005632:Fructose / Q000008:administration & dosage*; D005746:Gastric Emptying / Q000187:drug effects / Q000502:physiology*; D005947:Glucose / Q000008:administration & dosage*; D006801:Humans; D007773:Lactates / Q000097:blood; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010807:Physical Endurance / Q000502:physiology; D000077559:Sodium Citrate; D014867:Water; D015431:Weight Loss / Q000502:physiology; D055815:Young Adult
D002951:Citrates; D007773:Lactates; D014867:Water; D000077559:Sodium Citrate; D005632:Fructose; D005947:Glucose