We know that in sporting and occupational environments, whole body water immersion (WBI) is the most effective means of reducing core temperature following strenuous activity. However as a means of cooling firefighters on the fire ground, this method is timely, costly and often impractical. This study investigated alternative means of reducing core temperature, in comparison to WBI, in hot and humid environmental conditions. 

Twelve male and female firefighters (height 1.78 ± 0.04 m, weight 83.4 ± 7.64 kg, age 26.4 ± 2.36 yrs) performed a 20-minute fire suppression task followed by 20 minutes of active or passive cooling. In addition to WBI, cooling mechanisms included; hand and forearm immersion (HFI), forearm coverage with wet towels (WT) and shade (S). Temperature and relative humidity in the rehabilitation area ranged between 33.3 - 36.9˚C and 33 - 61% respectively and all rehabilitation water was temperate (23.4 - 28.8˚C).The study found core temperatures (TC) were significantly higher at the end of the 20-minute fire suppression task (average TC = 38.4 ± 0.34˚C, peak TC = 39.1˚C) compared to resting levels. Reductions in core temperature were observed in all four cooling mechanisms with the most-to-least effective mechanism listed as follows: WBI → ΔTC = -1.23 ± 0.50˚C, p<0.05; HFI → ΔTC = -1.00 ± 0.42, p<0.05; S → ΔTC = -0.78 ± 0.37˚C, p<0.05; WT→ ΔTC = -0.29 ± 0.34˚C, p<0.05. No statistical differences were detected between core temperature reductions in the WBI and HFI conditions, whereas as the WT and S conditions were significantly different to WBI. The answer to the study title – submersing your hands and forearms in water. This cooling technique yielded similar results to the gold standard, whole body immersion. If water immersion baths are not available or suitable in firefighting field operations, hand and forearm water immersion represents a practical means of reducing core temperature in hot and humid conditions.