There is no consent regarding the efficacy of cooling garments as a treatment for reducing heat strain for firefighters. To quantify whether cooling garments mitigate exertional heat stress in randomized controlled trials (RCTs) among firefighters, a systematic review and meta-analysis are performed to explore the issue by following the PRISMA checklist. The searched databases include PubMed, Embase, Google Scholar, Cochrane Library, and Web of Science from January 1999 to January 2021. The studies are constricted to RCTs where the performance of cooling garments is compared to non-cooling control groups. The primary parameters associated with heat strain are elucidated through measuring thermoregulatory (rectal temperature [Tre], mean skin temperature [sk]), metabolic (heart rate [HR], sweat rate [SR]), and perceptual (rating of perceived exertion [RPE], thermal sensation [TS]) indices from baseline to the end of the exercise. Pre-planned subgroup analyses provide information on whether the outcome of the treatment influences the type of cooling garments, cooled body area, and cooling before or after firefighting activities. Twelve eligible RCTs, including 105 firefighters (mean ± standard deviation age, 29.01 ± 7.15 years; 88% male), are considered for the meta-analysis. Here, ΔTre, Δsk, ΔHR, and TS show significant improvement after the cooling intervention, while no significant change is observed for ΔSR and RPE between the cooling and control groups. Evidence from the meta-analysis suggests that cooling garments are an effective adjunct therapy to mitigate exertional heat stress on firefighters compared to non-cooling treatment. Further, subgroup analyses suggest statistically significant influence facilitated by the type of cooling garments, but cooling before or after firefighting activities had no effect on exertional heat strain recovery. However, it must be noted that more RCTs are needed to confirm the present findings.
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