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Effect of dilute CHO beverages on performance in cool and warm environments

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journal contribution
posted on 09.01.2013, 12:39 authored by Phil Watson, Susan M. Shirreffs, Ronald J. Maughan
Purpose: This evaluated the efficacy of drinks containing low concentrations of carbohydrate (CHO; 2-6%) on physical performance in cool and warm environments. Methods: In two separate, but related studies, 24 healthy males completed a familiarisation trial and four trials to volitional exhaustion (TTE) at 70% VO2max in cool conditions (10C, n = 12) or 60% VO2max in a warm environment (30C, n = 12). Subjects ingested 0%, 2%, 4% or 6% CHO solutions (sucrose, glucose and fructose in a ratio of 50:25:25) immediately before exercise and every 10 minutes during exercise. Results: TTE in 10C was 102.6 ± 33.9 minutes, 109.2 ± 33.9 minutes, 121.0 ± 25.7 minutes and 122.4 ± 29.9 minutes in the 0%, 2%, 4% and 6% trials respectively (P = 0.012). Compared to the 0% trial, TTE was longer on the 4% (P = 0.032; ES 0.72) and 6% (P = 0.044; ES 0.66) trials. In addition, TTE was longer on the 6% trial than the 2% trial (P = 0.025). TTE was also significantly influenced by drink CHO content at 30C (0% 94.5 ± 24.5 minutes, 2% 104.1 ± 20.1 minutes, 4% 105.5 ± 26.7 minutes, 6% 112.0 ± 28.7 minutes; P = 0.046). No differences in TTE were apparent between 0% and the 2% or 4% trials, but TTE was longer on the 6% compared to the placebo (P = 0.045; ES 0.62). Heart rate, core temperature or rates of substrate oxidation were not affected by drink CHO content. Conclusions: These results demonstrate significant improvements in exercise capacity over the placebo trial when 4% and 6% CHO solutions were ingested at 10C and a 6% CHO drink at 30C.

History

School

  • Sport, Exercise and Health Sciences

Citation

WATSON, P., SHIRREFFS, S.M. and MAUGHAN, R.J., 2012. Effect of dilute CHO beverages on performance in cool and warm environments. Medicine and Science in Sports and Exercise, 44 (2), pp.336-343.

Publisher

Lippincott, Williams & Wilkins (© American College of Sports Medicine)

Version

AM (Accepted Manuscript)

Publication date

2012

Notes

This is a non-final version of an article published in final form in the journal, Medicine and Science in Sports and Exercise: http://journals.lww.com/acsm-msse/

ISSN

0195-9131

eISSN

1530-0315

Language

en