Shift-work Health - Arne Lowden

Background

Many groups in society live and work at atypical hours. This implies to plan for relevant lighting. Today integrative lighting provides appropriate visual ergonomics, comfort and atmosphere, and considerations to biological needs. Complaints from shift workers of insufficient sleep is partly explained by a mismatch of circadian alignment of internal circadian clock of the worker and work1.

Objective

As lighting technology is improving, new advice for shift work lighting has been introduced. We here highlight some lighting considerations that improve health, performance and safety.

Methods

Based on laboratory work and new findings in circadian regulation, attempts have been made to also test and implement light solutions in the field. Here, mainly field studies are reported.

Results

All published studies of light interventionshow positive ways of manipulating circadian systems especially in combination with of other interventions such as use of dark goggles, melatonin medication or changed sleep/wake scheduling2. But still there is a lack of randomized control studies that include circadian measures. Since the apparent difficulty in blinding bright light treatment (BLT) the particular role of placebo has to be considered and the long-term health effects are unclear. Light exposure outside work may produce either phase advances or delays and BLT has to be planned differently according to shift characteristics such as permanent night work, quick/slow rotation, and demands on readjustment after work. Several strategies have been evaluated such as use of intermittent BLT, amber light at night, dynamic light adjusted to time of day and filtering out various wavelengths.

Conclusion

Systems that provide circadian adaptation are particularly useful for groups having scheduled shiftwork or exposed to seasonal, geographical factors and windowless rooms lacking daylight exposure.