Bergen, J. L., Bearden, S., Anderson, E., & Haymes, E. M. (1998). Carbohydrate supplementation improves performance during high-intensity intermittent exercise in the heat. Medicine and Science in Sports and Exercise, 30(5), Supplement abstract 23.

This study compared an 8% CHO fluid-supplement with a placebo during intermittent high-intensity exercise in 35 degrees Celsius. Ss (M = 8; F = 8) cycled one minute on, one minute off at 80% VO2max consuming 2.5 ml/kg every 15 minutes. A trail was 2 x 45 minutes with a 10-minute between exercise rest interval.

The CHO supplement significantly increased time to exhaustion. Males lasted 2.4% longer and females 4.1% longer. Most trials were terminated because of high temperatures but the CHO trial stalled temperature increase. Blood lactates were higher after the CHO trial than the placebo trial.

A CHO supplement improved performance and stalled temperature increase in intermittent high-intensity exercise in the heat.

Implication. Playing high-intensity intermittent-exercise games in the heat requires CHO drink supplementation if performance standards are to be prolonged.

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