Workplace lighting for improving alertness and mood in daytime workers

Area of Science:

• Occupational Health
• Environmental Psychology
• Chronobiology

Background:

• Light exposure significantly impacts mood and alertness.
• Daytime workers may experience insufficient or inappropriate light, leading to mood disturbances and reduced alertness.

Purpose of the Study:

• To evaluate the effectiveness and safety of various lighting interventions for improving alertness and mood in daytime workers.

Main Methods:

• Systematic review and meta-analysis of randomized controlled trials (RCTs) and controlled before-after (CBA) trials.
• Searched multiple databases up to January 2018.
• Assessed risk of bias and used GRADE system for quality of evidence.

Main Results:

• High CCT light may improve alertness (very low quality evidence) but not mood.
• Individually applied blue-enriched light may enhance alertness and mood (very low quality evidence).
• Different proportions of direct/indirect light and morning vs. afternoon bright light showed no significant differences in mood or alertness (low quality evidence).

Conclusions:

• Very low-quality evidence suggests high CCT light may improve alertness in daytime workers.
• Low-quality evidence indicates no significant impact of varying direct/indirect light proportions on mood or alertness.
• Further research with higher quality evidence is needed to confirm the benefits of specific lighting interventions.