Acute Caffeine Mouth Rinse Does Not Change the Hydration Status following a 10 km Run in Recreationally Trained Runners

Abstract

Background and Aims. Caffeine mouth rinsing has emerged as an alternative to oral caffeine consumption for improving performance without provoking lower gastrointestinal distress. However, it remains unclear if hydration status and sweat rate are negatively affected by caffeine mouth rinsing. This study is aimed at evaluating the effects of 10 seconds of caffeine mouth rinsing (1.2% anhydrous caffeine solution) on hydration status and sweat rate following a 10 km run trial. Methods. Ten recreationally trained runners (30.1±6.4 y) volunteered to participate in this double-blind, placebo-controlled, and crossover research study. Participants completed two 10 km run trials separated by approximately one week. Immediately prior to running, participants completed a 10-second mouth rinse protocol with either 300 mg of caffeine or microcrystalline cellulose (placebo) diluted in 25 mL of water. The effects of caffeine mouth rinsing on hydration status and sweat rate were assessed following a 10 km run trial. Results. Sweat rate (placebo: 15.34±9.71 vs. caffeine: 11.91±6.98 mL·min−1; p=0.39), dehydration (placebo: 1.20±0.57 vs. caffeine: 1.49±0.29%; p=0.15), and hydration (placebo: 15.32±9.71 vs. caffeine: 11.89±6.99 mL·min−1; p=0.37) measures were not significantly different between trials. Conclusion. Caffeine mouth rinse does not appear to alter the hydration status or sweat rate following a 10 km run.

Acute caffeine mouth rinse does not affect attention and hand-eye coordination in recreationally active adults

“…The ergogenic mechanisms related to caffeine MR are not exactly clear, but some mechanisms have also been speculated. Caffeine MR may inhibit adenosine through direct binding to adenosine receptors found in oral cavity and/or through activation of bitter taste receptors located in the oropharyngeal epithelia which can activate gustatory neural pathways and stimulate regions of the brain associated with information processing and reward [1,20,30]. Caffeine mouth rinsing is a new form of caffeine supplementation.…”

Spit It Out: Is Caffeine Mouth Rinse an Effective Ergogenic Aid? A Systematic Review and Meta-Analysis

“…After duplicate removal (n 5 45), records were screened by titles and abstracts (n 5 35), resulting in 13 exclusions. The remaining records were assessed for methods (n 5 22), 9 of which were excluded for the following reasons: (a) coadministration of carbohydrate with caffeine-no Caff-MR only session (n 5 3) (15,36,45), (b) congress/conference abstracts (n 5 2) (33,47), (c) no sports performance-related outcomes (n 5 3) (12,26,48), and (d) assessed the chronic effects (4 weeks) of Caff-MR (n 5 1) (43). Two studies (44,56) were identified through manual screening from the reference list of the included articles, while 1 further study was found through social media (Twitter, Inc.) (27).…”

Compositional Aspects of Beverages Designed to Promote Hydration Before, During, and After Exercise: Concepts Revisited

“…However, several studies have reported a lack of effect of caffeine intake on acute fluid balance [ 154 , 155 ], particularly when combined with exercise [ 156 , 157 ]. Similarly, mouth rinsing with caffeine does not appear to have any impact on hydration during exercise [ 158 ]. A pooled analysis of 16 studies reporting data on the impact of caffeine intake on urine output concluded that the mild diuretic effects of caffeine observed in resting individuals are blunted with exercise, which was shown to be independent of dose and timing [ 153 ].…”