Mikko Härmä, MD, PhD, is a research professor on working hours, sleep and ageing in the Finnish Institute of Occupational Health (FIOH). He is currently leading several epidemiological studies on the association of shift work with health using payroll-based registry data. Mikko Härmä has a long experience on the research of shift work, working hours, jet-lag and sleep deprivation and the related individual differences on sleep and health using both observational and experimental studies. He is the honorary member (fellow of the society) of the International Working Time Society and has been rewarded by the Ministry of Social Affairs and Health on successful research for the extension of work careers in Finland through the development of “health-friendly” shift schedules.