Acute Caffeine Administered in Chewing Gum May Improve Functional Firefighting Balance After Gamma-Aminobutyric Acid Supplementation: A Double-Blind Crossover Trial.
Caffeinated chewing gum demonstrated significantly better completion time and performance index for functional firefighting balance tests after GABA supplementation, with small-to-moderate effect sizes, suggesting it may enhance functional balance performance through increased sympathetic nervous system activity.
Key Findings
Results
Caffeinated chewing gum significantly improved functional firefighting balance completion time compared to caffeine-free gum after GABA supplementation.
The CAF trial demonstrated significantly better completion time (p = 0.011; Cohen's d = 0.54) compared with the CG trial
Effect size was described as small-to-moderate
Tests were conducted while participants wore approximately 25 kg of full firefighting gear
Caffeinated chewing gum significantly improved the performance index of functional firefighting balance tests compared to caffeine-free gum.
The CAF trial demonstrated significantly better performance index (p = 0.012; Cohen's d = 0.43) compared with the CG trial
Effect size was described as small-to-moderate
Both completion time and performance index were used as indicators of the functional firefighting balance tests
Results
Salivary α-amylase concentration, a marker of sympathetic nervous system activity, was significantly higher in the caffeinated gum trial after testing.
Salivary α-amylase concentration was significantly higher in the CAF trial compared with the CG trial after testing (p = 0.040; Cohen's d = 0.45)
Effect size was small
Authors suggested increased sympathetic nervous system activity may be one reason for improved functional firefighting balance performance
Results
Heart rate variability measures (HR, SDNN, RMSSD, LF, and HF) showed no significant condition-by-time interactions between the caffeinated and caffeine-free gum trials.
There were no significant interactions in HR, SDNN, RMSSD, LF, and HF (condition*time, p > 0.05)
There was a significant interaction in LF/HF ratio (p = 0.040); however, further statistical analysis revealed no significant differences across trials or over time (p > 0.05)
Methods
The study employed a double-blind randomized crossover design with a specific supplementation protocol combining GABA and caffeine in chewing gum.
Fourteen active-duty elite firefighters completed functional firefighting balance tests wearing approximately 25 kg of full firefighting gear
After a 1-hour resting period, participants ingested GABA and rested for an additional 15 minutes
Participants then chewed either caffeine-containing gum (CAF) or caffeine-free gum (CG) for 10 minutes
Functional firefighting balance tests were repeated 15 minutes after gum ingestion
What This Means
This research suggests that chewing caffeinated gum can improve balance performance for firefighters who have taken a GABA (gamma-aminobutyric acid) supplement beforehand. The study tested 14 experienced firefighters wearing roughly 25 kg of full gear on balance tasks before and after taking GABA and then chewing either caffeinated or regular gum. Firefighters who chewed the caffeinated gum completed the balance tests faster and with better overall performance scores compared to those who chewed plain gum, and these differences were statistically significant with small-to-moderate effect sizes.
The researchers also found higher levels of salivary α-amylase — a biological marker linked to the body's sympathetic ('fight or flight') nervous system — in the caffeinated gum group after testing. This suggests that caffeine may have partially counteracted the calming effects of GABA by boosting sympathetic nervous system activity, which in turn may have helped the firefighters maintain better balance and coordination. Interestingly, traditional heart rate variability measures did not show clear differences between the two groups, highlighting that salivary α-amylase may be a more sensitive indicator of sympathetic activation in this context.
This research suggests that in operational settings where firefighters might use GABA supplements (for example, to aid recovery or reduce stress), a dose of caffeine delivered via chewing gum could help restore or even enhance physical performance, particularly for tasks requiring balance and coordination while wearing heavy equipment. However, the study was small (14 participants) and conducted under controlled laboratory-like conditions, so further research with larger groups and real-world firefighting scenarios would be needed before drawing firm practical conclusions.
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Tseng M, Wu C, Shiu Y, Tsou Y, Lin H, Chiu C. (2026). Acute Caffeine Administered in Chewing Gum May Improve Functional Firefighting Balance After Gamma-Aminobutyric Acid Supplementation: A Double-Blind Crossover Trial.. Nutrients. https://doi.org/10.3390/nu18172876