Shift work, which is associated with a disturbance in the synchronization of circadian physiological processes in the human body with natural 24-hour day-night rhythm, is associated with a number of diseases. Since the identification of a new non-visual photoreceptive mechanism that is active in regulating physiological processes, the influence of light on the circadian rhythms has been investigated under laboratory conditions. To support better understanding of a possible connection between shift work and health risks, studies of personal light exposures in field studies are of great importance.
A total of 85 nurses from the Klinikum Dortmund and the King’s College Hospital in London took part in the joint study by the Federal Institute for Occupational Safety and Health (BAuA) and the Public Health England (PHE). The nurses in Dortmund (42) were either shift workers who worked in three 8-hour shifts (early, late and nightshift) or 8-hour day working nurses. The nurses in London (43) did either a 12-hour shift (day and nightshift) or an 8-hour day shift. They recorded light exposure both during and outside working hours for a week and in three seasons (winter, spring and summer) using a detector attached to the chest.
The goal was to identify the characteristic features of the light exposure of this profession. To estimate the light exposure effective for the non-visual system, the light exposure in the blue spectral range was considered. In addition, the illuminance is also recorded, relating to the influence of light on the visual system. The following applies to the two light exposures:
Unit 2.2 "Physical Agents"