Effect of diet upon ventilation and effort perception during a physical stressor

The present research explored the effects of a high and low carbohydrate diet on ratings of perceived exertion (RPE) during a 10 minute bicycle ergometer test at high physical work capacity (70% of maximum aerobic capacity). Twelve female student volunteers participated and were randomly assigned the order of diet treatments in which they served as their own control and/or experimental group. Following each dietary regimen, subjects were instructed to pedal the bicycle ergometer for ten minutes at an intensity of 70% of their maximum capability. Throughout the cycling protocol, RPE scores were recorded at 2, 4, 6, 8, and 10 minutes; in addition expiratory gases were collected and analyzed by a computerized indirect calorimetry system. Results in the current investigation indicated that an increased carbohydrate intake resulted in an "ergogenic" or "work-producing" effect by attenuating the metabolic acidosis, possibly diminishing the sensations of the central cardiopulmonary effort, further attenuating the psychophysiological perceptions of effort. Conversely, ingestion of a low carbohydrate diet resulted in accentuation of the ventilatory drive eliciting higher signals of exertion during dynamic exercise.