This content was originally published on the OSRAM Digital Systems blog. You can read the original blog post here.

How often have we heard a frazzled parent explain a teenager’s irritable mood on lack of sleep? We all know that sleep plays a critical role in our mood and our levels of concentration and alertness. Through numerous research studies, we now know that quality of sleep also affects long-term health and overall wellbeing. Poor sleep is linked to physical problems such as a weakened immune system and mental health problems such as anxiety and depression.

(Image: Osram)

The National Sleep Foundation states “circadian rhythm (also known as your sleep/wake cycle or body clock) is a natural, internal system that’s designed to regulate feelings of sleepiness and wakefulness over a 24-hour period. This complex timekeeper is controlled by an area of the brain that responds to light, which is why humans are most alert while the sun is shining and are ready to sleep when it’s dark outside.”

According to the Lighting Research Center at Rensselaer Polytechnic Institute, disruption of this 24-hour rhythm of light and dark affects every one of our biological systems, from DNA repair in single cells to melatonin production. The human body reacts to sunlight and darkness by altering the release rate of hormones (melatonin) that direct our internal clock. Circadian disruption is linked to the disruption of the sleep-wake cycle—feeling sleepy during the day and experiencing insomnia at night. 

The natural 24-hour cycle helps maintain alignment of circadian biological rhythms along with basic processes that help our bodies to function normally. “Light of the appropriate quantity, spectrum, timing, duration, and distribution can have a profound effect on sleep, alertness, and performance, and can be used to reduce symptoms associated with conditions such as Alzheimer’s disease, insomnia, and depression.” – Lighting Research Center

Quality Sleep and Eldercare

Older adults, regardless of whether they are aging in place or are in long-term care facilities, tend to not spend time regularly outdoors and often may spend their days and nights in dimly lit rooms. Individuals in long-term care facilities are particularly vulnerable to exposure to artificial light because twenty-four hour nursing activities and safety concerns require constant lighting. "Excessive exposure to nighttime lighting disrupts these essential processes and can create potentially harmful health effects and hazardous situations." – American Medical Association

Alzheimer’s and other dementias are common among older adults, causing mild to severe memory loss, which makes it difficult to carry out daily activities. As many as 5 million Americans over the age of 65 are living with dementia and this number is expected to almost triple by 2050. Alzheimer’s patients are particularly susceptible to sleep disorders, agitation and depression.

But there is hope for this growing population. Light therapy may be part of the solution and it’s non-invasive and also relatively easy to incorporate. In a study conducted by the National Center for Health Research (NCHR), lights were installed in an Alzheimer’s facility to mimic daylight. Initial results found a significant increase in sleep quality and caregivers reported a significant decrease in depression and agitation in the participants. Additionally, recent research has shown that poor sleep may directly affect the onset and progression of Alzheimer’s disease, and conversely, healthy sleep may prevent or slow progression of the disease.

Human Centric Lighting (HCL) and Circadian Rhythm

Studies have shown that dynamic lighting solutions simulating the natural course of daylight significantly improve mood, concentration, productivity as well as alertness.

Using intelligent lighting control systems and tunable light fixtures, HCL mimics the natural rhythms of light found in nature. It dynamically adjusts the brightness and color temperature of the lighting to imitate the natural course of daylight. This means activating cold blue light during the morning and slowly transitioning to a relaxing warm white light into the late afternoon and evening.

During the morning, brightness levels are increased and light with a higher blue content is used. Blue light has a stimulating impact and addresses the cells in the retina that regulate our internal clock and our bodily functions. Blue light exposure cues the body to be in daytime mode, with its associated states of elevated alertness, improved attention spans, and reduced sleepiness.

As the day progresses, HCL reduces blue light and delivers warmer red light in the afternoon and into the evening. Warmer light has a relaxing effect that promotes easier sleep by enabling the body to wind down. Exposure to warmer light is very important, as recent scientific studies have pinpointed blue light as a major factor suppressing the production of the hormone melatonin, which is instrumental at regulating the sleep-wake cycle.

Using intelligent lighting control systems for HCL is just one simple yet effective strategy to help elders regulate their circadian rhythm. Among its many benefits, HCL can lead to a good night's sleep, resulting in significant improvements in overall health, quality of life and daytime functioning.