A laboratory-based experimental protocol for inducing psychophysiological stress in firefighters under controlled environment

This is the authors' abstract. We don't add key points for this paper.

Firefighting imposes concurrent physical and cognitive demands, whereas few laboratory paradigms replicate these dual-task challenges. This study developed an experimental protocol for inducing psychophysiological strain in firefighters. Twenty male firefighters (25.8 ± 3.4 years) completed a structured protocol consisting of a speech task (ST), a combined task involving load carriage with serial subtraction, and a physical task simulating hose-running. Salivary cortisol, α-amylase (sAA), dehydroepiandrosterone (DHEA), heart rate variability (HRV), and electrodermal activity were measured. Results showed marked activation of the endocrine responses, with significant increases in cortisol (122%), sAA (108%), and DHEA (138%) (all p < 0.001). Additionally, heart rate increased significantly during the ST (p = 0.007). HRV indices demonstrated pronounced autonomic modulation across stress stages. These findings support the protocol as a standardised tool for simulating occupational stress in firefighters, with potential applications in strain monitoring, protective equipment design, and wearable system development.