Have you ever set your “internal clock” to wake you up at a certain time in the morning? Did it work? We all move through our lives with the patterns set by our circadian rhythms, governed by our body’s biological clocks housed deep within our brains.
They affect our sleep-and-wake cycles, eating habits, digestion and other bodily functions. Internal clocks running too fast or too slow have been linked to chronic health problems.
You may be thinking, “What does all this have to do with landscape lighting?” According to many doctors, lighting can significantly affect one’s circadian rhythm. Artificial light can affect a human’s alertness level and suppress melatonin, the natural sleep hormone. The blue wavelength given off by fluorescent and LED lamps cause brain stimulation and alertness.
Most LED light sources are born blue. Phosphors are applied to a blue diode to change their color. The blue light energy passes through the phosphor layer and creates white light energy. Darker-colored phosphors provide a warm white Kelvin temperature, while lighter-colored phosphors produce a cooler white. Even so, the blue-light wavelength is still present.
While landscape lighting and the effect it may have on circadian rhythms isn’t a hot industry topic, I’m here to educate you on possible future impacts. In many areas, we’ve had to change the way we design outdoor lighting to comply with International Dark Sky requirements. In the future, lighting control and color temperature will be key in creating circadian-rhythm-friendly lighting systems.
When designing a circadian-rhythm-friendly lighting system, consider effects with warmer kelvin temperatures. Work with indirect techniques such as backlighting and downlighting. Individual zones and dimmers should be used to control brighter effects. If these areas can be seen through windows, they may need to be dimmed or switched off entirely. Research has shown that most red and amber LEDs are free of any blue wavelength.
Currently, these types of lamps are required by wildlife agencies in areas where sea turtles migrate. Try using amber lamps in pathway lighting, step lights and wall sconces. Using these lamps can successfully illuminate pathways and support nighttime navigation, while minimizing the amount of light to the human eye.
To maintain a healthy circadian rhythm, doctors suggest that we limit our use of all screen devices 30 minutes to an hour before retiring for the evening. This will slow down stimulation to the brain and allow our internal clocks to get in line. Here’s to all of us getting a good night’s sleep. Pleasant dreams!
Kevin Smith is the national technical support and trainer at Brilliance LED LLC, Carefree, Arizona, and can be reached at firstname.lastname@example.org.