Background:Global healthcare systems have been under huge pressure since Coronavirus Disease 2019 (COVID-19) was declared a pandemic. It is critical to prevent further spread of COVID-19 and to protect health workers from infection. This study aims to figure out short-term physiological impact on health workers induced by working in isolation wards for hours with personal protective equipment (PPE), so as to provide insights on reducing physiological impact and infection risk of health workers.Methods:Health workers who had worked in COVID-19 isolation wards for at least five weeks in Wuhan, China were recruited. Parameters including lung function, heart rate, oxygen saturation and weight were respectively measured before and after they worked in isolation wards. Comparison and regression analyses were conducted. Correlations between changing levels of measured parameters (lung function and heart rate) and baseline characteristics (body mass index, age, and working duration) were also analyzed. Results: After working in isolation wards for four to nine hours, the forced vital capacity (FVC) of health workers (74.32±17.59 versus 81.28±16.35, P<0.001) as well as weight (54.79 (48.50, 61.00) versus 55.50 (48.90, 61.00) P<0.01) showed significant decrease, while HR showed significant increase (110.31±14.65 versus 103.94±16.38, P=0.04). Correlation between BMI and the decline levels of FEV1/FVC (β=2.87, P=0.02) and correlation between BMI and the decline levels of FEF25-75 % predicted (β=1.80, P<0.05) were reported.Conclusions:After working in COVID-19 isolation wards with PPE for four to nine hours, the lung function of health workers declined. The decline levels were associated with BMI. HR increase and weight loss were reported. In order to reduce the potential infection risk of health workers, the balance between working duration and physiological changes should be considered when making shifting schedule.