Resumen de The Effects of Postexercise Consumption of High-Molecular-Weight Versus Low-Molecular-Weight Carbohydrate Solutions on Subsequent High-Intensity Interval-Running Capacity
Chris McGlory, James P. Morton
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.
