The effects of postexercise consumption of high-molecular-weight versus low-molecular-weight carbohydrate solutions on subsequent high-intensity interval-running capacity.
The aim of this study was to determine the effects of postexercise ingestion of different-molecular-weight glucose polymer solutions on subsequent high-intensity interval-running capacity. In a repeated-measures design, 6 men ran for 60 min in the morning at 70% VO2max. Immediately post- and at 1 and 2 hr postexercise, participants consumed a 15% low-molecular-weight (LMW) or high-molecular-weight (HMW) carbohydrate solution, at a rate of 1.2 g of carbohydrate/kg body mass, or an equivalent volume of flavored water (WAT). After recovery, participants performed repeated 1-min intervals at 90% VO2max interspersed with 1 min active recovery (walking) until volitional exhaustion. Throughout the 3-hr recovery period, plasma glucose concentrations were higher (p=.002) during the HMW and LMW conditions than with WAT (M 7.0±0.8, 7.5±1.0, and 5.6±0.2 mmol/L, respectively), although there was no difference (p=.723) between HMW and LMW conditions. Exercise capacity was 13 (43±10 min; 95% CI for differences: 8-18; p=.001) and 11 min (41±9 min; 95% CI for differences; 2-18: p=.016) longer with HMW and LMW solutions, respectively, than with WAT (30±9 min). There was no substantial difference (2 min; 95% CI for differences: -5 to 10; p=.709) in exercise capacity between LMW and HMW solutions. Although this magnitude of difference is most likely trivial in nature, the uncertainty allows for a possible small substantial enhancement of physiological significance, and further research is required to clarify the true nature of the effect.
McGlory
Chris
C
Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, UK.
Morton
James P
JP
D001628:Beverages; D001786:Blood Glucose / Q000378:metabolism*; D018592:Cross-Over Studies; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000493:pharmacokinetics*; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D008970:Molecular Weight; D018482:Muscle, Skeletal / Q000378:metabolism; D010101:Oxygen Consumption; D005082:Physical Exertion / Q000502:physiology*; D012420:Running / Q000502:physiology*; D013647:Task Performance and Analysis; D014867:Water; D055815:Young Adult
D001786:Blood Glucose; D004040:Dietary Carbohydrates; D014867:Water