Research carried out at the Surrey Sleep Centre at the University of Surrey in partnership with Philips Lighting has revealed that changing traditional white-light lighting to blue-enriched white light helped office workers stay more alert and less sleepy during the day.

The research also showed improvements in subjective measures of positive moods, work performance, fatigue in the evening, irritability, ability to concentrate and focus and eye strain. Furthermore the workers reported improved sleep at night.

The blue-enriched white light is thought to be more effective because it targets a recently discovered novel photoreceptor in the eye.

The research was conducted on 104 white-collar workers on two office floors. After baseline assessments under existing lighting conditions, every participant was exposed to two new lighting conditions, each lasting 4 weeks.

One consisted of blue-enriched white light (17 000 K) and the other of white light (4000 K). The order was balanced between the floors. Questionnaire and rating scales were used to assess alertness, mood, sleep quality, performance, mental effort, headache and eye strain, and mood throughout the 8-week intervention.

Professor Derk-Jan Dijk, who lead the experiment comments, “This research may indeed imply that our currently used artificial office lighting is suboptimal for maintaining alertness. “

The research was published in the Scandinavian Journal of Work, Environment & Health.