COGNITIVE FUNCTION IS BETTER WITH CARBOHYDRATE SUPPLEMENTATION IN THE HEAT

Bailey, S. P., Henderly, B., & Fernandez, J. (2009). Performance in a virtual environment and cognitive function during prolonged exercise in the heat. ACSM 56th Annual Meeting, Seattle, Washington, Presentation Number 713.

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This study determined if performance in virtual environment and cognitive function are similarly influenced by two hours of exercise in the heat and carbohydrate supplementation. Males (N = 10) completed four trials. During each trial, Ss cycled at 60% of ventilatory threshold for two hours in a normal (~22C and 50% humidity) or hot (~33C and 70% humidity) environment. Every 30 minutes during exercise Ss drank 5 ml/kg of body weight of a 6% carbohydrate beverage or a placebo. Ss completed a virtual environment task and a cognitive assessment battery before and after one and two hours of exercise. The virtual environment task was 10 minutes in length and was set in an urban warfare setting. The cognitive assessment battery assessed grammatical reasoning, code substitution, math processing, and tapping.

Heart rate and core temperature were elevated in the hot condition however, no differences existed between the carbohydrate and placebo treatments. No differences existed in the number of enemy killed or wounded during the virtual environment task across conditions. The number of enemy rounds encountered and the number of failures encountered during the virtual environment task was greater during the placebo than the carbohydrate treatment. Performance in the cognitive assessment battery was better in the hot than in the normal condition and in the carbohydrate than in the placebo treatment. Reaction time during code substitution was faster in the carbohydrate treatment than in the placebo. The number of correct answers during math processing was also greater in the carbohydrate than in the placebo treatment.

Implication. Cognitive function and performance of a virtual environment task are better following prolonged exercise in the heat when carbohydrate is consumed. When exercising in the heat, carbohydrate consumption should be increased.

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