Humans have evolved and adapted to living life in a circadian rhythm, which, of course, is based on daylight, said a group of speakers at the Environments for Aging Conference on Monday in Baltimore. 
"So why do we design spaces for seniors that don't use circadian rhythm lighting?" asked Drexel University Professor Donald McEachron. "Generally, we have not taken the biology of our elders into account and understood what circadian rhythms do when we design these spaces." 
McEachron was accompanied by Drexel University Professor Eugenia Ellis and David Kratzer, associate professor at Philadelphia University. 
"The disruption of the natural circadian rhythm has been found to prevent sound sleep and increase the risk of heart disease, and breast and colon cancer," Kratzer explained. "And the use of the lightbulb has changed how we work, sleep and eat."
McEachron said a sign that a circadian rhythm was in check is when a person wakes up naturally before their alarm clock goes off. A circadian dysfunction can happen when a person doesn't get enough sleep or is suddenly waken from sleep. He compared that person's rhythm to a band without a conductor. 
"That person will have decreased efficiency, gradual loss of function, and there will be wear and tear on the bodies other operating systems (immune, nervous, etc)," McEachron said. "So why are we designing facilities with lighting that does the exact opposite? We know now that living by a circadian rhythm is good, so we should be putting them on the most powerful, coherent light-dark cycle you can possibly get."
Ellis offered these tips for designers:
– When picking colors for a facility, wear yellow glasses. This will mimic the yellowing effect in aging eyes and help designers pick colors that can be distinguished more easily. 
– When designing indoors, indirect lighting is best, Ellis said. Direct lighting can cause too much of a glare and possibly cause falls. Also, don't use a flooring surface that will create a glare. 
– Think about backlighting. Using natural light is great, but don't position furniture or activities in a space that will cause the people sitting in front of windows to be backlit and turn into shadows. This could make it hard for a person with dementia to even see the other person's facial features, Ellis said. 
– Color contrast is important, she said. Make sure the color of the floor and the walls are different enough for a person with dementia to make the distinction. This is also important in a bathroom because if every aspect — from the walls, to the toilet to the sink — are white, it would be hard for a person to even see one thing from another.
– If possible, choose LED lighting. The bulbs have the potential to imitate something closer to real daylight, Ellis said. At night, use red lights to help residents calm down and get ready for sleep. Operators and nurses can even leave red lights on because the resident will be able to still see if they way up, but it will not disrupt their circadian rhythm, Ellis said. 
"We recommend the lighting of a facility be gradually ramped up during the day and then reduced at night," Ellis said. "And when designing the lighting features of a facility, it's important to not only measure the horizontal sight lights, but also the vertical. A resident may not always be looking straight ahead."