Active versus passive cooling during work in warm environments while wearing firefighting protective clothing

Area of Science:

• Occupational Health
• Environmental Physiology
• Firefighter Safety

Background:

• Firefighting protective clothing (FPC) and self-contained breathing apparatus (SCBA) increase heat strain in hot environments.
• Effective cooling strategies are crucial for mitigating heat stress in firefighters during demanding tasks.

Purpose of the Study:

• To evaluate the efficacy of active cooling (forearm submersion, mister) versus passive cooling in reducing heat strain for firefighters wearing FPC and SCBA.
• To compare the impact of different cooling methods on tolerance time and physiological responses.

Main Methods:

• Fifteen male firefighters underwent heat-stress trials in 35°C and 50% relative humidity.
• Participants engaged in intermittent work (50 min work, 30 min rest) involving walking.
• Cooling strategies (forearm submersion, mister, passive cooling) were applied during rest phases until predefined physiological limits were reached.

Main Results:

• Forearm submersion and mister significantly increased tolerance time and total work time compared to passive cooling.
• Forearm submersion yielded significantly greater tolerance time and work time than the mister.
• Active cooling strategies led to lower increases in rectal temperature, heart rate, and skin temperature compared to passive cooling.

Conclusions:

• Forearm submersion is a highly effective active cooling strategy for firefighters wearing FPC and SCBA in the heat.
• Active cooling, particularly forearm submersion, offers a distinct advantage over passive cooling in mitigating heat strain and enhancing firefighter performance.
• Implementing effective cooling protocols is vital for firefighter safety and operational endurance in hot conditions.