Comprehensive assessment of the functional state of firefighters under heat stress conditions

This article presents a comprehensive assessment of the impact of ambient temperature and standardized physical activity on the functional state of firefighters. During the experiment, 40 volunteer firefighters performed five stages of activity with a power ranging from 35 to 171 W in a heat chamber at 20, 25 and 30 °C. Heart rate (HR) and blood oxygen saturation (SpO2) were recorded. It was found that an increase in temperature to 30 °C during extreme activity causes an increase in HR to 196±6 bpm -1 and a decrease in SpO2 to 91,0±0,6%. A nonlinear nature of the HR increase was revealed: every additional 1 °C increases the heart rate by 0,7 bpm -1 during light work, and by 1,1 bpm -1 during heavy work. The obtained quantitative dependencies are recommended for using to adjust the effective work time in compressed air breathing apparatus and to prevent heatstroke in personnel.