Indoor lighting can have a dramatic effect on our health, impacting our sleep patterns, sense of wellbeing and even intelligence. A study conducted last year at the University of Michigan found that changes in environmental light leads to structural changes in the brain. Because people spend a huge amount of time in indoor lighting, the kind of light that we are exposed to is critically important to our health.
In the study they found that rats, who were exposed to dim lights, showed impairments in spatial learning. The researchers discovered that sustained exposure to dim light led to significant reductions in a peptide in the brain that helps to maintain healthy connections andirons in the hippocampus and in the dendritic spines, which are the connections that allow neurons to “talk” to one another. The findings of the study were reported in the journal Hippocampus.
Fortunately, as the body of research into lighting and health has grown, so has the understanding of and capabilities in designing solid-state lighting in order to contribute to specific health outcomes. Greg Kay, President of Lightology and a lighting designer, has been working with tunable white lighting to enhance health. “I wanted to see if new technology and proper lighting can enhance the lives of individuals with dementia using tunable white lighting to effect circadian rhythms. The second goal was to reduce falls.”
Kay’s company, Lightology, did a study in a nursing home, where lights are on 24 hours a day. The lighting was about 6000K, which is much too bright for your average 80-year-old, Kay said. They adjusted the light spectrum during the day, which helped with suppressing melatonin production (the hormone that helps us sleep). They reduced the lighting to 4100K from 4 to 6 p.m., 2700K from 6 to 8 p.m., and then lights out in bedrooms at 8, with hall lighting kept at 2700K.
Another change that they made was in night lighting. They installed rope lighting, made possible now with the use of tiny LED lights. The rope lighting was used to outline the beds. Bright overhead lighting bleaches rhodopsin, which is also known as “visual purple”. This light-sensitive receptor is key to maintaining night vision. So they replaced glaring fluorescent overhead lighting in bathrooms with lights that could be dimmed, and installed amber LEDs on the handrails.
Not only did the residents sleep better, but the number of falls were reduced and even the 2nd and 3rd shift workers reported feeling more alert. They saw a decrease in behaviors connected with dementia. Additional benefits include energy savings as well as decreased coffee consumption among workers! The bottom line, Kay said, is “Using LEDs to their full potential, adding tunable white lighting and circadian lighting to the mix.”
Lights and children
Bright lights in the evening was proven in a recent study to suppress melatonin production almost completely. The study, published in Physiological Reports in March 2018, exposed ten children, ages 3 to 5, to bright light for one hour before bedtime. They found that melatonin was suppressed for about an hour after the light was turned off, which was well into their sleep period. The finding was that the bright light disrupts sleep patterns. This built on a previous study of adolescents, which reported a greater sensitivity to light exposure in 9 to 16-year olds than in 3 to 5-year olds.
Into the future
With so much understanding about the correlation between light and health, architects, medical and educational facility managers and lighting designers are working together toward solutions. The Light and Health Alliance, based at the Lighting Research Center at Rensselaer Polytechnic Institute (RPI), is a collaboration that aims to enable the adoption of lighting for human health. The Alliance and the National Institute for Occupational Safety and Health released a series of short videos on the science of lighting for human health. The nine videos cover topics including circadian stimulus, lighting for older adults, lighting for office workers and future directions.
In the video, Mariana Figueiro, Ph.D. , a professor and director at the Lighting Research Center RPI, notes that the lighting industry is shifting to an approach that considers the impact of lighting on health. This “human-centric lighting” focuses on the amount of circadian stimulus that a person is exposed to throughout the day. They’re developing software programs that can help develop the best lighting at the right time for specific situations or individual people. In the future eyeglasses may control circadian stimulus exposure. Such lighting control will improve alertness, cognitive performance, sleep, mood, energy and health.
Written by Anne Fischer, Managing Editor, Novus Light Technologies Today