Effect of carbohydrate and prolonged exercise on affect and perceived exertion

Effect of a carbohydrate mouthwash on running time-trial performance

The aim of the present study was to determine the effect of a carbohydrate mouthwash on running time-trial performance. On two separate occasions, seven recreationally active males (VO2max 57.8 ml x kg(-1) x min(-1), s = 3.7) completed a preloaded (15 min at 65%VO2max) time-trial of 45 min in duration on a motorized treadmill. At 6-min intervals during the preload and time-trial, participants were given either a 6% maltodextrin, 3% lemon juice solution (carbohydrate trial) or a 3% lemon juice placebo mouthwash (placebo trial) in a double-blind, randomized crossover design. Heart rate, oxygen consumption (VO2), respiratory exchange ratio (RER), and ratings of perceived exertion (RPE) were measured during the preload, and blood glucose and lactate were measured before and after the preload and time-trial. There were no significant differences in distance covered between trials (carbohydrate: 9333 m, s = 988; placebo: 9309 m, s = 993). Furthermore, there were no significant between-trial differences in heart rate and running speed during the time-trial, or VO2, RER or RPE during the preload. Blood lactate and glucose increased as a result of the exercise protocol, with no between-trial differences. In conclusion, there was no positive effect of a carbohydrate mouthwash on running performance of approximately 1 h duration.

The influence of water ingestion during prolonged exercise on affect

This study examined the influence of water ingestion on affect and perceived exertion during sub-maximal running. Fifteen endurance-trained men performed two counterbalanced 90-min treadmill runs at 70% V O2 max. No fluid was ingested during one trial (NF-trial), whereas a single water bolus (5.0 mLkg(-1) body mass) was ingested immediately preexercise and every 20 min during exercise (2.0 mLkg(-1) bodymass) in a fluid replacement trial (FR-trial). Affect and perceived exertion were repeatedly assessed and physiological changes monitored. Perceived exertion and heart rate increased significantly during the run but there were no differences between conditions. Such similarities were not reflected in the pleasure-displeasure ratings, which were maintained above baseline levels during exercise in the FR-trial but declined below baseline during the NF-trial. A significant postexercise improvement in rated pleasure-displeasure was found only in the FR-trial, leading to significantly higher ratings of pleasure-displeasure during the recovery period compared to the NF-trial. Self-reported Energy was also enhanced postexercise only in the FR-trial. Body mass decrease was significantly larger and thirst ratings were significantly higher in the NF-trial compared to the FR-trial. In summary, water ingestion attenuated the during-exercise decrease in pleasure-displeasure and elicited an improvement after prolonged, submaximal running.

Carbohydrate ingestion during prolonged high-intensity intermittent exercise: impact on affect and perceived exertion

This study was designed to determine the effects of ingesting a carbohydrate (CHO) solution on affective states and rating of perceived exertion (RPE) during prolonged intermittent high-intensity exercise. Seventeen male soccer players completed a prolonged intermittent high-intensity exercise protocol for 90 min on two occasions, separated by at least 7 days. Participants consumed either a 6.4% CHO (0.6 g/kg body mass (BM)/h) or an artificially sweetened placebo (PLA) solution immediately before (8 mL/kg BM) and every 15 min (3 mL/kg BM) during exercise in a double-blind, counterbalanced design. Pleasure-displeasure, perceived activation, RPE and plasma glucose concentration was assessed. The results showed that compared with the CHO trial, perceived activation were lower in the placebo trial during the last 30 min of exercise and this was accompanied by lowered plasma glucose concentrations. In the CHO trial, RPE was maintained in the last 30 min of exercise but carried on increasing in the PLA trial. Therefore, CHO ingestion during prolonged high-intensity exercise appears to elicit an enhanced perceived activation profile that may impact upon task persistence and performance. This finding is in addition to the physiological and metabolic benefits of the exogenous energy supply.