Circadian Potency Spectrum with Extended Exposure to Polychromatic White LED Light under Workplace Conditions

Abstract

Overview

Electric light has revolutionized how humans inhabit the night, yet exposure to light during nighttime can disrupt the circadian rhythms, leading to various health disorders.

Research Objective

The study aimed to establish a detailed definition of circadian spectral sensitivity that accommodates adequate lighting for visual tasks without disrupting the human circadian timing system.

Methodology

• Prior studies used short monochromatic light exposures in dark-adapted conditions to define the circadian spectral sensitivity curve.
• This study employed long-term (12-hour) exposure to six types of polychromatic white LED light at recommended workplace illumination levels (540 lux).

Findings

We identified a narrower spectral sensitivity in light-adapted conditions, predominantly at 477 nm peak sensitivity, providing insights for developing LED lighting that minimizes circadian disruption.

Conclusion

The derived circadian potency spectral sensitivity curve supports the development of spectrally engineered LED lights that balance circadian stimulation during the day and circadian protection at night, addressing the health risks associated with nocturnal light exposure.