Circadian lighting is a generic term used to describe lighting designs that support alignment of circadian rhythms to a day-active and night-sleeping pattern. The lighting approach offers the additional potential to increase alertness during working hours. As interest in circadian lighting grows, the lighting industry is developing metrics and products while validating approaches.
This article provides a refresher on circadian lighting and focuses on three recent studies pointing to potential benefits.
The circadian system produces and regulates bodily functions based on 24-hour cycles, or circadian rhythms. One critical function is the timed release of melatonin, which tells the body it’s time to sleep. Disruption of this internal clock can lead to poor nighttime sleep and health disorders.
Until the invention of electric lighting, the daylight cycle regulated circadian rhythms. Today, many people spend most of their time indoors, so electric lighting plays a very important role. However, traditional lighting design focuses on vision and visual comfort, not circadian response.
For circadian response, the key factors are quantity of light falling on the eye’s photoreceptors during the day, requiring sufficient light level on a vertical visual plane; spectrum or wavelength of light; when light is received by the eye; and the amount of time of light exposure.