Abstract
Emergency personnel operating in high-temperature environments while wearing protective equipment experience substantial thermophysiological strain, impairing performance and increasing the risk of heat-related illnesses. This systematic review and meta-analysis evaluated the effects of cooling interventions on core temperature, skin temperature, heart rate, sweat rate and tolerance time in emergency personnel exposed to heat stress. A comprehensive search was conducted in PubMed-MEDLINE, Web of Science and Cochrane Library databases up to March 2024. Controlled experimental studies published in English or Spanish were included if they assessed cooling interventions (pre-, per-, intermittent, or post-cooling; internal vs. external methods) in participants wearing protective clothing in heat stress conditions (> 28 °C), and included a non-cooling control group. Twenty studies met the inclusion criteria. Cooling interventions significantly reduced core temperature (ES = - 0.56, p < 0.001), heart rate (ES = - 0.42, p = 0.001), and sweat rate (ES = - 0.70, p < 0.001), while improving tolerance time (ES = 1.44, p = 0.003). Intermittent and per-cooling approaches, particularly those employing mixed-method strategies (e.g., cooling vests with immersion or ice slurry ingestion), yielded the greatest benefits. No significant changes were observed in skin temperature. Cooling interventions effectively mitigate physiological strain in emergency personnel exposed to heat stress. Intermittent and per-cooling using combined methods appear most effective. Nonetheless, logistical constraints may limit field implementation, highlighting the need for further research to optimize practical cooling protocols.