Occupational heat stress and the role of wearable cooling interventions: A systematic review and meta-analysis of physiological and perceptual outcomes

Background: Occupational heat stress, driven by high ambient temperatures, humidity, radiant heat impairs health, safety, and productivity. Wearable cooling technologies (e.g., water/ice, phase-change materials [PCM], ventilated/evaporative garments), among the interventions for mitigating heat strain is increasingly used, but their comparative effectiveness remains unclear. Present systematic review aimed to evaluate the effectiveness of wearable cooling intervention on physiological and perceptual outcomes during heat exposure.Methods: PubMed, Embase, and Scopus (May 2024) were searched for randomized or non-randomized intervention trials in workers or acclimatized adults, adhering to PRISMA guidelines (PROSPERO: CRD42025631559), Data were extracted as means/SDs (or transformed equivalents) and pooled using random-effects meta-analysis. Heterogeneity (I²), small-study effects (Egger’s test), sensitivity/subgroup analyses, and a network comparison of cooling modalities were performed. Risk of bias (RoB 2, ROBINS-I) and certainty (GRADE) were assessed.Findings: Sixty-two studies were included. Post-exposure, wearable cooling significantly reduced rectal temperature (mean difference [MD] –0.24 °C; 95% CI –0.35 to –0.12; I²=97%), gastrointestinal temperature (MD –0.17 °C; –0.29 to –0.04; I²=72.34%), skin temperature (MD –1.02 °C; –1.76 to –0.27; I²=95.48%), and heart rate (MD –7.14 bpm; –10.99 to –3.28; I²=61.78%). Egger’s tests suggested possible small-study effects for skin temperature and heart rate but not for core temperatures. Network and subgroup analyses indicated more consistent benefits with water/ice and PCM garments. Overall certainty ranged from low to very low due to risk of bias, inconsistency, and imprecision.Interpretation: Wearable cooling attenuates physiological heat strain and improves thermal comfort, particularly via water/ice and PCM systems. Given high heterogeneity and low certainty, adequately powered, standardized, head-to-head trials are needed to refine comparative effectiveness and guide scalable implementation in occupational settings.