HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Lieberman, H. R Articles by Slade, S. S Search for Related Content PubMed PubMed Citation Articles by Lieberman, H. R Articles by Slade, S. S Agricola Articles by Lieberman, H. R Articles by Slade, S. S

Carbohydrate administration during a day of sustained aerobic activity improves vigilance, as assessed by a novel ambulatory monitoring device, and mood^{1,2,3,4,5,6,7}

¹ From the Military Nutrition Division, US Army Research Institute of Environmental Medicine, Natick, MA (HRL, CMF, and SSS).

Background: The brain requires a continuous supply of glucose to function adequately. During aerobic exercise, peripheral glucose requirements increase and carbohydrate supplementation improves physical performance. The brain's utilization of glucose also increases during aerobic exercise. However, the effects of energy supplementation on cognitive function during sustained aerobic exercise are not well characterized.

Objective: The effects of energy supplementation, as liquid carbohydrate, on cognitive function during sustained aerobic activity were examined.

Design: A double-blind, placebo-controlled, between-subjects design was used. Young, healthy men (n = 143) were randomly assigned to 1 of 3 treatment groups. The groups received either a 6% (by vol) carbohydrate (35.1 kJ/kg), 12% (by vol) carbohydrate (70.2 kJ/kg), or placebo beverage in 6 isovolumic doses, and all groups consumed 2 meals (3200 kJ). Over the 10-h study, the subjects performed physically demanding tasks, including a 19.3-km road march and two 4.8-km runs, interspersed with rest and other activities. Wrist-worn vigilance monitors, which emitted auditory stimuli (20/h) to which the subjects responded as rapidly as possible, and a standardized self-report mood questionnaire were used to assess cognitive function.

Results: Vigilance consistently improved with supplemental carbohydrates in a dose-related manner; the 12% carbohydrate group performed the best and the placebo group the worst (P < 0.001). Mood-questionnaire results corroborated the results from the monitors; the subjects who received carbohydrates reported less confusion (P = 0.040) and greater vigor (P = 0.025) than did those who received the placebo.

Conclusions: Supplemental carbohydrate beverages enhance vigilance and mood during sustained physical activity and interspersed rest. In addition, ambulatory monitoring devices can continuously assess the effects of nutritional factors on cognition as individuals conduct their daily activities or participate in experiments.

Key Words: Cognition • psychomotor performance • brain • aerobic exercise • glucose • ambulatory monitoring • energy • ergogenic aids • nutritional supplements

This article has been cited by other articles:

				S. N. Cheuvront, R. Carter III, M. A. Kolka, H. R. Lieberman, M. D. Kellogg, and M. N. Sawka Branched-chain amino acid supplementation and human performance when hypohydrated in the heat J Appl Physiol, October 1, 2004; 97(4): 1275 - 1282. [Abstract] [Full Text] [PDF]