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Lighting: A Path to Health

by Andy McAllister

Sleep is essential to health and just plain awesome. It regulates hormone cycles, recovers the muscles, and promotes rejuvenating and balancing effects on the digestive system, immune system, and nervous systems. Chances are you are not getting enough of it. This could be caused by many things, but one of the most overlooked factors affecting your quality and quantity of sleep is light.

Our bodies have evolved to tune into the rhythms of day and night. This biological rhythm, or internal clock, is called the circadian rhythm. It tells your body when to be awake and when to sleep. The primary control of the circadian system comes from an external source — light. We wake up to bright sunlight, are awake during daylight hours, calm down at dusk as light levels decrease and rest during darkness. You may have noticed how your mood can vary greatly from sunny to overcast days.  During fall/winter months, people often complain of seasonal affectedness, with symptoms similar to depression, due to the short duration of daylight. This is due to the diminished amount of light received at the eye during these times and can have negative effects on a person’s health.

In recent years, design cultures have begun to understand the value of quality light in the buildings they design. Many projects now utilize daylighting strategies to bring in natural light. However, these have mostly been geared towards creating pleasant interior environments, views to the outdoors, or reducing electric energy consumption. Even with the focus on light, the amount of light provided during peak hours of the day still does not compare to the time spent in the intense sunlight found outdoors (A blue sky has color temperature of 7000k to 10000K). Most electrical lighting systems provide just enough light to illuminate a worksurface or floor (Candle light is 1000-1500K; standard bulbs around 3000-4000K). Therefore, occupants generally are not exposed to enough light at the proper color temperatures to stimulate the circadian system. We also watch TV, look at devices, and stare at computers that stimulate the light receivers in our eyes at odd hours and can throw off the synchronization between our brains and the sun. All these things can affect our receptiveness to the circadian rhythm, and due to the negative effects of not sleeping properly, could contribute to chronic health maladies such as diabetes and obesity.

Circadian lighting systems are part of the future package of a well-designed building. Studies have confirmed the connections between light and wellness. WELL Certified™ buildings are even rewarded for efforts made to align the artificial lighting environment with levels comparable to the environment in which we have evolved. The design industry should feel empowered to include a circadian lighting in every project. However, they are often skeptical of its benefits or financially restrained to include such a system. Advances in controls and lighting technologies have brought these systems down in cost, making a circadian lighting system much more attainable. You may have even noticed such features included in the latest operating system for your iPhone called “Night Shift” where the brightness and color of light changes with the time of day. That is exactly what circadian lighting systems can do. Using a tunable LED fixture, one that has controllable temperature and color composition, is one of the most common circadian electric lighting systems. Sensors and timers integrate with a controller to modulate the color and intensity of lights to properly stimulate the circadian system.

When building or designing a project, it is important to consider many factors of human wellness. Lighting design, whether utilizing natural or artificial, can have a dramatic effect on all occupants of a building. Consider a circadian lighting system also referred to as “Human Centric Lighting.” The positive effects on all occupants could be dramatic. Connections to natural light and adequate lighting levels have been shown to increase worker productivity and enhance moods immediately. Long-term exposure has the potential to lead to overall healthier occupants. The opportunity is available to help reduce health care costs and create more balanced bodies and minds in all who use and occupy the spaces we design. Who doesn’t want to work and associate with happier, healthier people after a good night’s rest?

Harvard School of Public Health: https://9foundations.forhealth.org/
International Well Building Institute: https://www.wellcertified.com/
National Sleep Foundation – Circadian Rhythm: https://sleepfoundation.org/sleep-topics/what-circadian-rhythm
Sleep.org: https://sleep.org/
Metropolis Magazine – Circadian Lighting Solutions: https://www.metropolismag.com/design/circadian-lighting-survey/
WalaLight Healthy LED lighting system: https://www.walalight.com/
Human Centric Lighting Society: http://humancentriclighting.org/
Watt Stopper: https://www.legrand.us/wattstopper.aspx