Objective Occupational heat stress, driven by high ambient temperatures, humidity, and radiant heat impairs health, safety, and productivity. Among the interventions for mitigating heat strain, wearable cooling technologies [eg, water/ice, phase-change materials (PCM), ventilated/evaporative garments] is increasingly used, but their comparative effectiveness remains unclear. This systematic review aimed to evaluate the effectiveness of wearable cooling intervention on physiological and perceptual outcomes during heat exposure.

Methods Adhering to PRISMA guidelines (PROSPERO: CRD42025631559), we searched PubMed, Embase, and Scopus (February 2026) for randomized or non-randomized intervention trials among workers or acclimatized adults. Data were extracted as mean/standard deviation (or transformed equivalents) and pooled using random-effects meta-analysis. Heterogeneity (I2), small-study effects (Egger’s test) and sensitivity/subgroup analyses of cooling modalities were performed. Risk of bias (RoB 2, ROBINS-I) and certainty (GRADE) were assessed.

Results Sixty-nine studies were included in our review. Post-exposure, wearable cooling significantly reduced rectal temperature [mean difference (MD) -0.24°C; 95% confidence interval (CI) -0.37– -0.1; I²=43.91%], gastrointestinal temperature (MD -0.26°C; -0.52– -0.001; I²=98.13%), skin temperature (MD -1.14°C; -1.85– -0.42; I²=96.56%), and heart rate (MD -7.69 bpm; -11.22– -4.15; I²=73.19%). Egger’s tests suggested possible small-study effects for skin temperature and heart rate but not for core temperatures. 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.

Conclusions 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.

Key terms core body temperature; heart rate; heat strain; heat stress; meta-analysis; occupational heat strain; occupational heat stress; perceptual outcome; phase-change material; physiological outcome; systematic review; wearable cooling intervention

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