Shift work duration and heatstroke risk among healthcare workers during hot summer months: A modelling study across 34 Chinese cities

Abstract

Heat stress issues in healthcare workers (HCWs) have been widely recognized but no published guidelines have clearly specified healthy shift work hours and the time to experience heatstroke while performing healthcare tasks in outdoor settings. Using a rational biophysical model and hourly meteorological data collected during sixty hot summer months (June–August 2002–2021) in 34 major Chinese cities, this study determined healthy shift work hours and heatstroke risks in HCWs with three levels of body mass index (BMI = 18.0, 23.0, and 27.0 kg/m2) while performing healthcare tasks. Our simulation results found that HCWs should switch shifts every 2 h. HCWs with a higher BMI could see their shifts extended by 10–28 min. HCWs with 18.0 kg/m2 BMI should finish shifts 10–23 min earlier than their counterparts. Heatstroke can strike HCWs in 143 min. HCWs should not wear impermeable PPE suits outdoors for >2 h in cities other than Guiyang, Qingdao, Kunming, Xining, and Lhasa for safety reasons. To ensure 8 h of healthy labor, HCWs are advised to wear personal cooling systems with a cooling power of ≥194.8 W/m2 or to work in testing booths, where HVAC setpoint temperature for PPE-clad HCWs is 25.0 °C, with RH = 50–65 % and a fanning speed of 2.5 m/s.