Does circadian lighting work?

To put it simply, yes. Much scientific research has been conducted over the last 70+ years to reveal how light affects circadian rhythms. Many studies have also been conducted analysing the benefits of exposure to light at the right times of the day and the implications of exposure at the wrong time of the day.

Some of the benefits of circadian lighting are:

Increased productivity
Increased concentration
Improved sleep
Improved mood
Less risk of developing certain mental and physical health conditions
Reduction in errors and accidents
Faster cognitive processing
Increased alertness in the morning
Can aid with the rehabilitation of certain medical conditions, e.g. brain injuries

The science behind circadian lighting:

The circadian rhythm is a natural cycle that follows a daily sequence. It is approximately 24 hours in length and enables an organism to predict and adapt to changes in the environment. There are clear brain wave activity patterns, hormone production, cell regeneration, and other biological activities linked to this daily cycle.

The colour and intensity of sunlight changes throughout the day, beginning with a warm amber light at sunrise, slowly changing into a cooler, brighter light during the day before warming back into an amber light at sunset.

The eye contains cells that react to these changes in light; it sends a signal to an area of the brain called the hypothalamus, which triggers the release of serotonin (the body’s natural antidepressant) during the day and melatonin (a hormone affecting sleep) at night. This creates our circadian rhythm and promotes our mental and physical health, mood, and energy.

Although the circadian rhythm is produced due to natural factors within the body, the external environment can affect how it works. One of the most powerful synchronizers is light. Timing, intensity, duration, and wavelength of light all affect the human biological clock. The body’s master clock, or SCN, controls melatonin production, a hormone that makes you sleepy. It receives information about incoming light from the optic nerves, which relay information from the eyes to the brain. When there is less light—like at night—the SCN tells the brain to make more melatonin, so you get drowsy.

Light can speed up, slow down or reset sleep and wake times. For example, blue light suppresses melatonin production and is therefore used to treat disorders for sleep disturbances. LEDs appear to emit a bright white light, but in actual fact, LEDs contain high amounts of blue (in the 400-490 nm range). This blue light exposure is responsible for increased alertness and cognitive function, which can be useful for shift workers as they go against their natural body clocks schedule and need a bit of extra help to adjust. Studies have shown how blue light can help treat seasonal affective disorders such as SAD, increasing the amount of bright light in the darker winter months, replicating the amount of light exposure typical in British summertime.

A study from the Light Research Program at Thomas Jefferson University in Philadelphia found that blue light strengthens and stimulates connections between areas of the brain that process emotion and language. This means that blue light may, in turn, help people to handle emotional challenges better and regulate mood over time.

Blue light is prevalent in sunlight, so your body naturally absorbs the most during the summer and much less in the winter. Because of this, the researchers suggested that adding blue light to indoor atmospheres, as opposed to the standard yellow lights, which are typically used, may help boost mood and productivity year-round.

Over the past decade, neuroscientific research has uncovered the existence of a previously unknown non-visual optic pathway modulated by the substance melanopsin (which has a unique sensitivity to distinct parts of the visible light spectrum). Unlike other projections of the visual system, these pathways seem to play a minimal role in the perception and processing of vision and image-formation; instead, they have been found to be fundamentally responsible for the entrainment and maintenance of circadian rhythms and other physiological functions.

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Once you understand the scientific explanation of the impact light has, it is clear to see how it can benefit building occupants (especially those who spend a large proportion of their time indoors). It is only relatively recently that humans have begun to live indoors. Humans lived in caves and used daylight to hunt and gather; therefore, day-to-day activity centred around daylight. However, in a world where we are now always ‘on’ and constantly digitised, it is easy for our rhythms to become out of sync, e.g. sitting under a bright white office light all day, in front of a bright computer screen, finishing the working day and sitting in front of the TV all night whilst checking your emails and scrolling through social media – it is understandable why as many as 16m UK adults are suffering from sleepless nights.

Circadian lighting in the office can’t fix everything as, on average, people only tend to spend 8hrs of the day there; what they do for the rest of the 16hrs of the day will also have an impact. However, it is a start in the right direction, and it shows that as an employer, you care about your employee’s health and wellbeing. Recent studies have shown that office workers' productivity has increased by up to 20% following the introduction of human-centric lighting. There are also a variety of other metrics that can be analysed within the office in order to measure the effectiveness of circadian lighting, e.g. surveys and questionnaires can reveal how employee happiness and mood has improved, observation can reveal that employees are more alert, monitoring the tea and coffee supplies could reveal that employees are less reliant on caffeine and analysing sickness records can reveal how previous patterns of higher sickness especially in the winter months when it’s dark and depressing have improved.

Other environments, such as hospitals and care homes, where patients and residents spend a prolonged amount of time, are ideal environments to see a more profound impact. There are many case studies of how circadian lighting has benefited building occupants in these environments. Many of these benefits are short-term, before and after benefits, but the long-term effect is also extremely advantageous. The consequences of having a circadian rhythm that is out of sync for a prolonged period of time can lead to higher rates of conditions such as obesity, diabetes, depression, heart attacks and certain cancers. Therefore the long term benefits on occupants health could be huge.

Heanor Park care home installed an amBX Circadian Plus lighting system, and the results so far have been extremely promising. There has been a significant reduction in the number of falls a care home would usually experience; Heanor Park only had 2 falls within the first 3 months of opening – this could simply be because the level of illumination is higher, or it could be that residents are more alert and therefore more aware of their surroundings. In addition, as the lighting helps to entrain residents circadian rhythms, Heanor Park employees have noted residents are showing a greater level of engagement; they appear to feel more active and alert at the right times of the day and then as the lighting changes to mimic natural daylight throughout the day, by night time residents feel ready for bed and are getting a better night’s sleep. Click here to watch the case study video.

As a result of this, employees can encourage more of a routine for residents making night shifts in particular much easier as residents are sleeping and their body clocks are synced correctly. For staff working in these conditions, they have commented how surprisingly they don’t feel tired and can still carry out tasks and feel alert as the circadian lighting is not installed in the staff room and office. For employees working dayshift, the circadian lighting also entrains their circadian rhythm, meaning they also get a better night’s sleep. In the long term, the benefit of having circadian lighting and many other cutting-edge technological advancements in the care home means that residents can retain some independence and the care home itself appears elite compared with competitors. Heanor Park has also recently decided to install amBX Circadian Plus in another one of their care homes as a retrofit, again highlighting the benefits of circadian lighting. Please read the full case study of our care home lighting transformation here.

Circadian rhythms are now widely known within the fields of design and architecture. There is mounting pressure for spaces to be designed with the building occupant in mind - resulting in improved health and wellbeing. This is especially true now; the COVID-19 pandemic has made employees more aware than ever before of the environment they are working in and what is good for their health. Employees now demand more basic necessities within the workplace, and places like care homes also have to look at new ways of reassuring residents and families that lessons have been learnt and quality of care has improved.