Bright light can support healthy body rhythms, study claims

The light we encounter in our daily lives has a significant impact on our biological rhythms. People who have 24-hour access to artificial sunshine can interrupt their sleep and have a detrimental influence on their health, well-being, and productivity. However, a recent research looked at how bright lighting should be throughout the day and at night to maintain healthy body rhythms, peaceful sleep, and daily alertness.
The findings were reported in the journal ‘Plos One.’ 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 scientific experts to develop the first evidence-based, consensus recommendations for healthy daytime, evening, and nighttime light exposure.

These guidelines give much-needed assistance to the lighting and electronics sectors in order to aid in the creation of healthier settings and to enhance the lighting of our workplaces, public buildings, and residences.
The new paper addressed an important question: how to adequately assess the extent to which different forms of illumination may alter our biological rhythms and daily patterns of sleep and waking. Light influences these patterns through a particular type of cell in the eye that employs a light-sensitive protein called melanopsin, which is separate from the proteins found in rods and cones that support vision (and upon which traditional ways of measuring “brightness” are based).

Because melanopsin is particularly sensitive to light in a specific portion of the optical spectrum (blue-cyan light), the revised guidelines employed melanotic equivalent daylight illuminance, a newly designed light measuring standard adapted to this unique feature. Data analysis from a variety of laboratory and field studies demonstrated that this new measurement approach could provide a reliable way of predicting the effects of light on human physiology and body rhythms, and thus could serve as the foundation for widely applicable and meaningful recommendations.

The incorporation of the recommendations into formal lighting guidelines, which presently focus on aesthetic needs rather than consequences on health and well-being, will be an essential next step. Furthermore, when LED lighting technology advances and low-cost light sensors become more widely available, individuals will be able to more easily regulate their own light exposure to best support their own body rhythms in accordance with the new recommendations.

“These recommendations provide the first scientific consensus, quantitative, guidance for appropriate daily patterns of light exposure to support healthy body rhythms, night-time sleep and daytime alertness. This now provides a clear framework to inform how we light any interior space ranging from workplaces, educational establishments and healthcare facilities to our own homes,” Brown said.