In the case of "positive shift method", employees are transferred from morning shift to middle shift, from middle shift to night shift, and so on. In the case of "shift method", employees are transferred from morning shift to night shift and from night shift to middle shift, and so on. In the case of positive shift method, workers who work at night shift and early shift should work continuously for 16 hours (i.e. playing continuous shifts); In the case of shift work, workers in the middle shift and the early shift at night can only rest for 8 hours (that is, shift work).
For doctors and security guards, working at night is inevitable.