Our physiological rhythms are greatly influenced by the light we encounter in our daily lives. With 24-hour availability to artificial light and less exposure to natural daylight, modern lifestyles can interrupt sleep and have a detrimental influence on health, well-being, and productivity.
The topic of how bright lighting should be throughout the day and in the evening to promote healthy body cycles, peaceful sleep, and daily alertness is addressed in a new paper published on March 17th in the open access journal PLOS Biology.
Professors Timothy Brown of the University of Manchester in the United Kingdom and Kenneth Wright of the University of Colorado Boulder in the United States convened an international group of leading scientists to develop the first evidence-based, consensus recommendations for healthy daytime, evening, and nighttime light exposure.
These proposals give the lighting and electronics industry much-needed direction in order to help designers create healthier settings and improve how we light our workplaces, public buildings, and homes.
The new paper tackles a critical question: how to accurately evaluate the impact of different forms of lighting on our biological rhythms and daily sleep and awake patterns.
Light impacts these patterns through a particular form of cell in the eye called melanopsin, which is different from the proteins that support vision in the rods and cones (and upon which traditional ways of measuring “brightness” are based).
The new recommendations used a newly designed light measuring standard customized to this unique feature, melanopic equivalent daylight illuminance, because melanopsin is most sensitive to light in a specific portion of the optical spectrum (blue-cyan light).
Data from a variety of lab and field experiments showed that this novel measurement method might give a reliable way of forecasting the effects of light on human physiology and body rhythms, and hence could serve as the foundation for universally applicable and useful recommendations.
Integration of the ideas into formal lighting guidelines, which presently focus on visual needs rather than consequences on health and well-being, will be a critical next step.
Additionally, as LED lighting technology advances and low-cost light sensors become more widely available, individuals should be able to more easily regulate their personal light exposure to best support their own body rhythms in accordance with the new recommendations.
Brown continues, “These guidelines are the first quantified scientific consensus on acceptable daily light exposure patterns to maintain healthy body rhythms, overnight sleep, and daytime alertness.
This provides a clear foundation for how we light any interior area, including workplaces, educational institutions, and healthcare facilities, as well as our personal homes.”
