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

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.

KEYWORDS:

• Athletes
• endurance
• strength
• power
• ergogenic
• fatigue

Disclosure statement

Bryan Saunders has received caffeine supplements free of charge from Farmácia Analítica (Rio de Janeiro, Brazil) for experimental investigations. Farmácia Analítica had no involvement in the current manuscript.

Additional information

Funding

Gabriel Barreto (2017/15314-1) and Bryan Saunders (2016/50438-0) have been financially supported by Fundação de Amparo à Pesquisa do Estado de Sao Paulo. Bryan Saunders has received a grant from Faculdade de Medicina da Universidade de São Paulo (2020.1.362.5.2).