Practical Considerations for Using Personal Cooling Garments for Heat Stress Management in Physically Demanding Occupations: A Systematic Review and Meta-Analysis Using Realist Evaluation

Introduction: Due to rising temperature extremes, workplaces are seeking new solutions, such as using personal cooling garments (PCG) to mitigate and manage workplace heat exposure. This systematic review sought to assess the physiological and perceptual effects of PCGs on workers in standard work clothing performing moderate-to-heavy intensity tasks in hot environments.

Methods: A peer-reviewed search strategy was conducted in MEDLINE, Embase, CINAHL, Scopus, Global Health, and Business Source Complete with no language or time limits. A meta-analysis using a realist evaluation framework was then performed to evaluate the effectiveness of the PCGs.

Results: Thirty-three studies with 764 participants (98% male; average 21 ± 34 participants per study), conducted primarily in a laboratory setting (76%) were included. The studies were 193 ± 190 min in duration and consisted of a moderate-to-heavy work effort of 3.3 ± 1.0 METs in hot ambient conditions (temperature: 35.9 ± 3.3°C, 51.4 ± 12.1% relative humidity, wet bulb globe temperature [WBGT] 31.2 ± 2.6°C). The PCGs (n = 67) facilitated heat exchange through conduction (n = 39), evaporation (n = 4), convection (n = 2), radiation (n = 2), or hybrid combinations (n = 20). Conductive and hybrid PCGs offered the greatest thermoregulatory benefit, whereby core temperature (T_c) and heart rate (HR) reductions were consistently observed (Conductive: T_c: -0.3°C, HR: -12 bpm; Hybrid: T_c:-0.2°C, HR: -10 bpm), while PCGs directed at enhancing evaporative and radiative heat exchange had no or minimal effect on the physiological outcomes assessed (i.e., T_C < 0.1°C, HR: < 0.7 bpm).

Conclusion: While the PCGs had a positive overall effect, conductive options offered the most consistent benefit to workers. WBGT, clothing insulation, and duration of wear significantly affected some physiological and perceptual outcomes.