Personal protective equipment (PPE) provides health care workers with a barrier to prevent human contact with viruses like Ebola and potential transmission of the disease. However, PPE can also introduce an additional physiological burden from potentially increased heat stress. This study evaluated the human physiological and subjective responses to continuous light exercise within environmental conditions similar to those in West Africa while wearing 3 different, commonly used PPE ensembles (E1, E2, and E3).

Six healthy individuals were tested in an environmental chamber (32°C, 92% relative humidity) while walking (3 METs, 2.5 mph, 0% incline) on a treadmill for 60 minutes. All subjects wore medical scrubs and PPE items. E1 also had a face shield and fluid-resistant surgical gown; E2 additionally included goggles, coverall, and separate hood; and E3 also contained a highly impermeable coverall, separate hood, and surgical mask cover over the N95 respirator.

Heart rate and core temperature at the end of the exercise were significantly higher for E2 and E3 than for E1. Subjective perceptions of heat and exertion were significantly higher for E2 and E3 than for E1.

Heat stress and PPE training, as well as the implementation of a work-to-rest ratio that avoids dehydration and possible heat stress issues, are recommended. (Disaster Med Public Health Preparedness. 2017;11:580–586)

Experience with the use of personal protective equipment (PPE) ensembles by health care workers responding to the Ebola outbreak in the hot, humid conditions of West Africa has prompted reports of significant issues with heat stress that has resulted in shortened work periods.

A sweating thermal manikin was used to ascertain the time to achievement of a critical core temperature of 39°C while wearing 4 different PPE ensembles similar to those recommended by the World Health Organization and Médecins Sans Frontières (Doctors Without Borders) at 2 different ambient conditions (32°C/92% relative humidity and 26°C/80% relative humidity) compared with a control ensemble.

PPE ensembles that utilized coveralls with moderate to high degrees of impermeability attained the critical core temperature in significantly shorter times than did other ensembles. Encapsulation of the head and neck region resulted in higher model-predicted subjective impressions of heat sensation.

To maximize work capacity and to protect health care workers in the challenging ambient conditions of West Africa, consideration should be given to adjustment of work and rest schedules, improvement of PPE (e.g., using less impermeable and more breathable fabrics that provide the same protection), and the possible use of cooling devices worn simultaneously with PPE. (Disaster Med Public Health Preparedness. 2015;9:536–542)