Working Memory Before And After Exercise While Wearing Firefighter Personal Protective Equipment

PURPOSE: The present experiment sought to establish the effect of rapid heat stress (RHS) on experienced (5+ years of experience) firefighter's working memory. RHS describes uncompensable heat stress where metabolic heat production surpasses the heat loss capabilities of an environment created by high-level personal protective equipment, a common scenario in the fire-fighting world. Previous research has demonstrated a change in brain activity in response to RHS, leading to a decrease in overall cognitive ability. No studies have sought to determine the working memory ability of firefighters using the 2-Back test pre and post-RHS. METHODS: Five participants (5 males) completed the 2-back test using PsyToolKit. "2-Back" describes a specific form of the N-Back task in which participants must focus on a sequence of letters that individually appear on a computer screen and decide if they saw the same letter two trials ago. The test consisted of 60 total trials, and accuracy was recorded. The participants then performed a graded-exercise walking steady-state treadmill protocol in an environmental chamber (35 °C; 50% humidity) in full firefighter PPE until completing the protocol or reaching volitional maximum. Then, the participants completed the same 2-back test with randomization and recorded accuracy. RESULTS: A paired-sample t-test revealed no significant difference between the accuracy of the pre-RHS 2-back test (mean ± SD = 88.4 ± 8.1%) and post-RHS 2-back test (mean ± SD = 89.9 ± 4.2%) (p = 0.7185, t = -0.38294, df = 4.5075). CONCLUSION: These results demonstrate that RHS has no impact on the working memory of experienced firefighters. The conditions used in this study did not cause a statistically significant change in the accuracy of the 2-back test. Although speculative, these results could differ for novice firefighters with less experience in the RHS environment. Supported by: Collaborative Intramural Research Program (CIRP) LSU Health Shreveport