The ergogenic effects of caffeine ingestion (240–840 mg) on exercise performance is well established, albeit in some cases with negative side effects. However, recent evidence shows that much smaller doses can have beneficial effect on endurance performance as well as on mental function. Less is known about the possible synergistic effects of low dose of caffeine (CAF) and carbohydrate (CHO) feedings, especially as related to team sports performance. PURPOSE: To determine the effects of low dose (100 mg) CAF ingestion along with typically recommended CHO on physical and mental function during intermittent high intensity exercise that mimics the demands of competitive team sports. METHODS: Physically active male (N=6) and female (N=4) low to moderate caffeine users participated in this study. Experimental trials consisted of four ∼22-minute quarters (QTR) of shuttle running. Physical and mental function tests were administered throughout the experimental trial including (20-m sprint, vertical jump, gross motor skill test, force sensation, rating of perceived exertion, profile of mood states and psychomotor vigilance test).On four separate occasions, subjects received 20-oz of flavored water placebo (PLA), CHO, PLA+CAF and CHO+CAF prior to exercise. During exercise, subjects ingest PLA, CHO, PLA and CHO respectively (3.5 ml·kg-1). RESULTS: No difference was found in 20-m sprint time, vertical jump and gross motor skills performance between any treatments. However, both caffeine treatments (PLA+CAF and CHO+CAF) significantly improved psychomotor vigilance and reduced force sensation at HALFTIME (p<0.05). CHO+CAF also improved self-reported perception of fatigue, vigor and overall mood compared to PLA+CAF (p<0.05). Systolic blood pressure was increased with CHO+CAF compare to other three treatments. However, no difference was found in heart rate, core body temperature, plasma volume change, or hydration status between any treatments. CONCLUSION: The data suggest that ingestion of a low dose of caffeine prior to exercise did not add to the expected benefits of CHO feedings alone on physical tasks. However, all of the mental function tasks were significantly enhanced with the combination of CHO plus CAF, with little or no adverse side effects. Funded by Gatorade Sports Science Institute.

The ergonenic effects of caffeine ingestion on exercise performance is well established for endurance sports like running and cycling. Much less is known about its effects on team sport exercise, whether it can enhance the ergogenic benefits of carbohydrate feedings, and the extent to which mental as well as physical performance can be enhanced. PURPOSE: To determine the effects of caffeine ingestion along with a carbohydrate-electrolyte sports drink (CHO) on mental and physical function during intermittent high-intensity exercise that mimics the demands of competitive team sports. METHODS: Physically active male (N=6) and female (N=5) mild to moderate caffeine users completed three practice sessions followed by four experimental trials. Experimental trials consisted of four ∼15-minute quarters (QTR) of shuttle running at various intensities including walking, running, maximal sprinting, and jumping. Various physical and mental function tests (20-m maximal sprint, 15-repetition maximal vertical jumping, gross motor skill test, target-jumping accuracy test, force sensation, rating of perceived exertion, profile of mood states and Stroop Color-Word Test) were administered throughout the experimental trial. Heart rate, blood pressure, core body temperature, plasma volume change and body fluid loss were also measured. Subjects drank a 6% CHO-electrolyte solution (3 ml·kg1) before exercise, and immediately after QTR-1, QTR-2, HALFTIME, QTR-3 and QTR-4. Prior to QTR-1, subjects ingested capsules containing a placebo, 80, 120 or 400 mg caffeine (CHO-80, CHO-120 and CHO-400) in a repeated measures, double-blind, counterbalanced design. RESULTS: Compared with CHO alone, all 3 CAF doses produced similar benefits on some of the physical and mental function tests including faster 20-m sprint, higher average jump heights, improved self-reported perception of fatigue, vigor and overall mood state in the second half (p<0.05). Force sensation was also reduced post exercise, but only in CHO-400 (p<0.05). However, CHO-400 had a higher tension score, and small increases in heart rate, systolic blood pressure, and core body temp as compared to all other treatments. CHO-80 & CHO-120 were not different from CHO in these measures. Plasma volume change and body fluid loss were not different between any treatment. CONCLUSION: These findings suggest that ingestion of a low dose of caffeine (80 or 120 mg) prior to exercise adds to the previously reported benefits of CHO feedings on both physical and mental function during the latter stages of team sport exercise without negative side effects. Funded by Gatorade Sports Science Institute.