Effects Of Caffeine Chewing Gum On Exercise Performance: A Systematic Review And Meta-analysis

Caffeine is a widely consumed psychoactive substance and has been used to improve performance in sports and cognitive tasks for decades. New strategies of consumption are constantly being created, including caffeinated gum (Caff-gum). Caff-gum could be advantageous due to its faster release, with plasma values peaking approximately 15 minutes following ingestion. To date, no meta-analytical data exists supporting the use of Caff-gum for exercise performance. PURPOSE: To determine the influence of Caff-gum on exercise performance and to identify factors that could modify its effects. METHODS: Medline, EmBase, SPORTSDiscus, and ClinicalTrials.gov were searched for original investigations determining the effect of Caff-gum on exercise protocols involving healthy adults. A random-effects meta-analysis was performed to determine the effect of Caff-gum on exercise outcomes. Sub-analyses were performed according to exercise type (endurance, strength/power), dose (< or ≥ than 3 mg/kg), training status (trained or untrained) and timing (≤ or > 15 min prior). RESULTS: 14 studies, totalling 200 participants were included. Overall, Caff-gum improved exercise performance compared to placebo (SMD=0.21, 95%CI: 0.10-0.32; p=0.001). A significant beneficial effect was also shown for trained (SMD=0.23, 95%CI: 0.08-0.37; p=0.004), but not for untrained (SMD=0.14, 95%CI: -0.02-0.29; p=0.07) individuals. Both endurance (SMD=0.27, 95%CI: 0.12-0.42; p=0.002) and strength/power (SMD=0.20, 95%CI: 0.03-0.37; p=0.03) exercise benefitted from Caff-gum. Significant effects were shown when Caff-gum was provided within 15 min of exercise (SMD=0.27, 95%CI: 0.07-0.4; p=0.01), but not >15 min (SMD=-0.48, 95%CI = -1.7-0.82; p=0.25). An effect was shown when dose was ≥3 mg/kg BM (SMD=0.22, 95%CI: 0.07-0.37; p=0.01), but not when < 3 mg/kg (SMD=0.20, 95%CI: -0.03-0.43; p=0.07). CONCLUSION: Caff-gum supplementation may be considered an effective ergogenic strategy for trained athletes involved in both endurance and strength/power exercises, consuming a recommended dose of ≥3 mg/kg BM within 15 minutes of initiating exercise.