Send to

Choose Destination
Psychopharmacology (Berl). 2018 Apr;235(4):947-958. doi: 10.1007/s00213-017-4809-0. Epub 2017 Dec 15.

A caffeine-maltodextrin mouth rinse counters mental fatigue.

Author information

Human Physiology Research Group, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.
Endurance Research Group, School of Sport and Exercise Sciences, University of Kent at Medway, Chatham Maritime, Kent, ME4 4Ag, UK.
Human Physiology Research Group, Vrije Universiteit Brussel, Pleinlaan 2, 1050, Brussels, Belgium.



Mental fatigue is a psychobiological state caused by prolonged periods of demanding cognitive activity that has negative implications on many aspects in daily life. Caffeine and carbohydrate ingestion have been shown to be able to reduce these negative effects of mental fatigue. Intake of these substances might however be less desirable in some situations (e.g., restricted caloric intake, Ramadan). Rinsing caffeine or glucose within the mouth has already been shown to improve exercise performance. Therefore, we sought to evaluate the effect of frequent caffeine-maltodextrin (CAF-MALT) mouth rinsing on mental fatigue induced by a prolonged cognitive task.


Ten males (age 23 ± 2 years, physical activity 7.3 ± 4.3 h/week, low CAF users) performed two trials. Participants first completed a Flanker task (3 min), then performed a 90-min mentally fatiguing task (Stroop task), followed by another Flanker task. Before the start and after each 12.5% of the Stroop task (eight blocks), subjects received a CAF-MALT mouth rinse (MR: 0.3 g/25 ml CAF: 1.6g/25 ml MALT) or placebo (PLAC: 25 ml artificial saliva).


Self-reported mental fatigue was lower in MR (p = 0.017) compared to PLAC. Normalized accuracy (accuracy first block = 100%) was higher in the last block of the Stroop in MR (p = 0.032) compared to PLAC. P2 amplitude in the dorsolateral prefrontal cortex (DLPFC) decreased over time only in PLAC (p = 0.017).


Frequent mouth rinsing during a prolonged and demanding cognitive task reduces mental fatigue compared to mouth rinsing with artificial saliva.


Cognitive fatigue; Cognitive performance; Electroencephalography; Mouth rinse

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Springer
Loading ...
Support Center