# Novel cooling vest with personal protective equipment alleviates heat strain without increasing metabolic demands in the heat

## TL;DR

A new cooling vest helps reduce heat strain when wearing protective gear without increasing energy use in hot environments.

## Contribution

A novel carbon-based cooling vest is introduced that reduces heat strain without increasing metabolic demands during PPE use.

## Key findings

- The cooling vest reduced core temperature and heart rate compared to PPE alone.
- Thermal sensation improved significantly with the cooling vest.
- Metabolic energy expenditure remained unchanged with the cooling vest.

## Abstract

Wearing medical personal protective equipment (PPE) substantially increases heat strain by elevating metabolic heat production while impairing heat dissipation. Cooling vests are a practical countermeasure, yet their efficiency depends on thermal conductivity and comfort. This study examined the thermoregulatory and perceptual responses to PPE use and evaluated the efficacy of a novel carbon-based cooling vest with enhanced heat transfer capacity.

A randomized crossover design was employed in which 12 participants completed 100 minutes of simulated healthcare activity in a climatic chamber (32 °C, 70% RH) under three conditions: medical scrubs (NoPPE), scrubs with PPE (PPE), and scrubs with PPE plus the cooling vest (PPE+Vest). Physiological, thermoregulatory, and perceptual variables were continuously monitored across conditions.

Compared with PPE alone, PPE+Vest markedly attenuated heat strain, lowering core temperature [PPE 38.4, standard deviation (SD) 0.4, 0C versus PPE+Vest 37.5 (SD 0.4) 0C, P=0.001] and heart rate [PPE 123 (SD 11) bpm versus PPE+Vest 107 (SD 15) bpm, P<0.001], while improving thermal sensation [PPE 2.0 (SD 0.8) versus PPE+Vest 0.8 (SD 0.8), P=0.006]. These thermoregulatory benefits occurred without an increase in metabolic energy expenditure [PPE 317 (SD 50) kcal versus PPE+Vest 317 (SD 53) kcal, P=0.891].

The novel carbon-based cooling vest effectively suppressed heat storage by enhancing conductive heat transfer, leading to core and skin temperatures comparable to NoPPE. Importantly, despite its additional weight, the vest did not impose extra metabolic demands, offering a practical strategy to maintain thermal comfort and physiological stability during prolonged medical work in hot environments.