Connor, D. A., Strubeck, E., Brown, K. M., & Seifert, J. G. (2013). The influence of carbohydrate, protein, and caffeine on power output and response time. Medicine & Science in Sports & Exercise, 45(5), Supplement abstract number 1107.

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This study compared a commercially available carbohydrate + protein + caffeine sports gel (GEL) and a caffeine-alone supplement for auditory response time, power output , and metabolic responses during endurance cycling. Ss (N = 14) completed two cycling trials by ingesting the GEL (22.5g CHO/hour, 3.75g PRO/hour, 188 mg caffeine/hour) or caffeine-alone (256 mg caffeine/hour) along with 200 mL/hour of water during the two-hour exercise. Exercise was divided into 8 x 15-minute intervals of 13 minutes at 70% VO2max and two minutes at 90% VO2max. Blood glucose, reaction time, heart rate, rating of perceived exertion, and respiratory exchange ratio were also collected during the test. After the two-hour ride, Ss completed a six-minute cycling test where they attempted to maintain the greatest power output possible at a resistance of 5% BW.

The GEL supplement resulted in statistically greater mean power output, quicker reaction time; lower blood glucose levels, lower heart rate, and lower ratings of perceived exertion than the caffeine-alone treatment.

Implication. A commercially available gel supplement (carbohydrate, protein, and caffeine) significantly improved auditory reaction time and power output (by 5.7% and by 6.5%, respectively) compared to a caffeine-alone supplement even though the caffeine dose was 27% lower in the GEL supplement than the caffeine-alone supplement.

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