The aim of the study being to investigate chewing caffeine-containing gum could effectively improve firefighters' balance under conditions of brain fatigue.

14 healthy adult male active-duty firefighters as participants and used a crossover double-blind design, dividing them into a CAF trial and a PL trial. On the first day of the experiment, after the participants had taken sufficient time off and had a full night's sleep, they rested for 3 hours after dinner on the second day. Following the collection of saliva samples, baseline heart rate variability and firefighting ability tests were conducted. After the tests, the participants ingested 800 mg of GABA and rested for 30 minutes. After that, the participants chewed caffeinated gum containing 3 mg/kg (CAF trial) or caffeine-free placebo gum (PL trial) for 10 minutes, spit it out, rested for 15 minutes. The participants underwent eight firefighting balance tests, during which heart rate variability was measured. After the tests were completed, saliva samples were collected again.

Inclusion Criteria:

• Active-duty members of the Special Search and Rescue Brigade
• Regularly perform firefighting and disaster relief duties
• Have fully recovered from sports injuries such as strains or sprains for at least 3 months

Exclusion Criteria:

• Members who are not part of the Special Search and Rescue Brigade.
• Individuals who do not regularly perform firefighting and disaster relief duties
• Participants who have not fully recovered from sports injuries for at least 3 months

Only male subjects