Optimized office lighting advances melatonin phase and peripheral heat loss prior bedtime

Area of Science:

• Chronobiology
• Occupational Health
• Lighting Science

Background:

• Workplace lighting impacts circadian rhythms, sleep, and well-being.
• Optimizing indoor lighting may enhance circadian entrainment and hormonal regulation.

Purpose of the Study:

• To investigate the effects of optimized dynamic lighting on circadian phase markers in office workers.
• To compare the impact of dynamic versus standard office lighting on melatonin, cortisol, and skin temperature.

Main Methods:

• Participants (n=34) spent five workdays in two rooms: one with automated dynamic lighting (Test) and one with standard lighting (Reference).
• Collected data included individual light exposure, skin temperature, and salivary melatonin and cortisol levels.
• Vertical and melanopic illuminance levels were measured in both rooms.

Main Results:

• The Test room had significantly higher vertical (1177 lux) and melanopic illuminance (931 lux) compared to the Reference room.
• Participants experienced 50 minutes earlier accumulated light exposure in the Test room.
• Melatonin secretion onset and peripheral heat loss occurred significantly earlier in the Test room relative to bedtime.

Conclusions:

• Optimized dynamic workplace lighting can advance circadian phase markers, including melatonin onset and peripheral heat loss.
• This intervention may be beneficial for individuals experiencing delayed circadian timing.
• Dynamic lighting strategies hold potential for improving sleep and well-being in office environments.