Effects of caffeine chewing gum supplementation on exercise performance: A systematic review and meta-analysis

Abstract

ABSTRACT The aim of this systematic review with meta-analysis was to determine the effect of caffeine gum (Caff-gum) on exercise performance-related outcomes. Several databases were searched for studies assessing the effect of Caff-gum in placebo-controlled protocols involving healthy adults. Random-effects meta-analyses using standardized mean differences (SMD) were performed to determine the effect of Caff-gum on exercise outcomes with several sub-analyses (training status, exercise type, timing and dose) for potential modifying factors. 14 studies were included, totalling 200 participants. There was a significant overall effect of Caff-gum compared to placebo (SMD = 0.21, 95%CI: 0.10–0.32; p = 0.001). Subgroup analysis showed improved performance 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. Caff-gum improved 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) performance outcomes. Caff-gum was ergogenic when consumed within 15 min prior to initiating exercise (SMD = 0.27, 95%CI: 0.07–0.4; p = 0.01), but not when provided >15 min prior (SMD = −0.48, 95%CI = −1.7–0.82; p = 0.25). There was no significant effect of Caff-gum with doses <3 mg/kg body mass (BM) (SMD = 0.20, 95%CI: −0.03–0.43; p = 0.07), but there was a significant effect when the dose was ≥3 mg/kg BM (SMD = 0.22, 95%CI: 0.07–0.37; p = 0.01). Caff-gum supplementation may be an effective ergogenic strategy for trained athletes involved in both endurance and strength/power exercise, using a recommended dose of ≥3 mg/kg BM consumed within 15 min of initiating exercise. Highlights This study determined the effect of Caff-gum on exercise performance, using a systematic review and meta-analysis. Fourteen studies, totalling 200 participants performing a variety of endurance and strength/power exercise tests were included. The relative Caff-gum dose ranged from 1.27-4.26 mg/kg BM and timing ranged from 120 min prior to exercise up to intra-test application. Caff-gum was shown to be an effective ergogenic aid for trained individuals involved in both endurance and strength/power exercise. Supplement dose and timing modified the efficacy of Caff-gum. Supplementation with Caff-gum was effective when provided in doses ≥3 mg/kg BM and within 15 min prior to initiating exercise. Trained endurance or strength/power athletes seeking to benefit from caffeine in the form of chewing gum should supplement within 15 min prior to initiating an exercise task, in doses ≥3 mg/kg BM.