Holt, C., Bailey, S. P., Pfluger, K. C., Bartlett, S., Stripling, R., & Hall, E. E. (2006). Impact of carbohydrate supplementation on perceptual and affective responses to prolonged exercise in the heat. Medicine and Science in Sports and Exercise, 38(5), Supplement abstract 2008.

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The purpose of this investigation was to investigate the effects of carbohydrate supplementation on perceptual and affective responses during prolonged exercise in the heat. Males (N = 10) completed four exercise trials to volitional fatigue. During each trial, Ss cycled (Monark cycle ergometer) at a workload equivalent to 80% of ventilatory threshold. On two occasions, Ss exercised in a normal environment (~22C and 50% humidity). On the other two occasions, Ss exercised in a hot environment (~35C and 70% humidity). Every 30 minutes during exercise, Ss drank 5 ml/kgBW of either an 8% carbohydrate beverage or a water placebo. Ss were asked to provide responses to the ratings of perceived exertion scale (RPE), Feeling Scale, and Felt-Arousal Scale at rest, every 30 minutes during exercise, and at fatigue.

Time-to-fatigue was reduced during trials in the hot conditions and improved during CHO trials. Ratings of perceived exertion were higher at 30 and 60 minutes into the exercise in hot conditions. CHO supplementation reduced RPE at 60 minutes in the normal conditions. Responses to the Feeling Scale were affected negatively in the heat. CHO attenuated the negative response to the Feeling Scale at fatigue during exercise in the heat. Responses to the Felt-Arousal Scale increased during exercise to fatigue. No differences in the Felt-Arousal Scale were observed at any time point as a result of carbohydrate supplementation or thermal stress.

Implication. Perceptual (RPE) and affective (Feeling Scale and Felt-Arousal Scale) responses during prolonged exercise are influenced by carbohydrate supplementation and thermal stress. Those changes mirror the performance changes that occur.

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