A New Hand-Cooling Device to Enhance Firefighter Heat Strain Recovery

Abstract

This study tested a new portable cooling device for fire fighting recovery. Participants (N = 8) walked and did arm curls (time-weighted VO₂: 1.6 L· min⁻¹ on a treadmill for 40 min in a heated chamber (wet bulb globe temperature: 33.7°C; relative humidity: 40–45%) while wearing firefighter turn-out gear and self-contained breathing apparatus (SCBA). Immediately on finishing exercise, participants recovered for 40 min with either a hand-cooling device or seated passive recovery at an ambient temperature of 22°C, 35% RH in a repeated-measures counterbalanced design. The cooling device had little impact on recovery during the first 30 min; however, compared with passive cooling, the cooling device resulted in significantly lower rectal temperature (T_re) during the last 10 min. Relative to starting T_re of the recovery period, ΔT_re at 35 min had fallen 0.51 ± 0.19°C (passive) and 0.76 ± 0.30°C (active) (p = 0.03); and at 40 min ΔT_re had fallen 0.63 ± 0.17°C (passive) and 0.88 ± 0.31°C (active) (p = 0.03). Cooling capacity of the device calculated from ΔT_re over the whole recovery period averaged about 144% of passive. Reductions in heat storage enhance worker safety and performance in hot environments.

Keywords:

• heat strain
• personal cooling
• protective clothing
• rectal temperature

ACKNOWLEDGEMENTS

This research was supported by an equipment loan from AVAcore Technologies, Inc. The authors are in no way affiliated with AVAcore Technologies, Inc. We thank all the participants in this study.