Your circadian (latin f or “of the day”) rhythm controls many functions of your body. It is entrained or reset every day by exposure to light and dark – adjusting your body for the environment that it is in. Effectively, your body perceives the movement of the sun across the sky as refractions change both the colour and spectral distribution. This tells us to rest, sleep and heal during the night and then be alert and active during the day.
The best known cue to entrain circadian rhythm is light. Circadian lighting solutions (sometimes called bio-dynamic or human-centric lighting), which change throughout the day to emulate changing daylight, can have many benefits for patients in a healthcare environment who may not get exposure to natural daylight or may have to have light at night for examinations. Studies* have shown that you can improve recovery times, symptoms for Alzheimer’s and dementia sufferers, mood and behaviour, attention, performance and reduce errors.
However, just installing a lighting system that changes from cool white to warm white isn’t quite enough. Whilst there will be some benefits to the end user, it is vital that the light source has been biologically optimised to achieve a high melanopic lux in the daytime and low melanopic lux (or biological darkness) at night-time. Melanopic Lux refers to the eyes sensitivity to blue-enriched natural daylight whereas photopic lux (which is usually used for specifying a lighting system) is the measurement for how much light is needed for vision. We know that telling our bodies through light that it is daytime (artificially through blue enriched light or by spending time in natural daylight) can have tremendous health benefits: reducing dementia symptoms, reduction of depression, particularly in older women. Conversely, we know that telling our bodies it is daytime (by simulating high sun in the sky with high blue light content) when it is actually night time can be damaging, reducing expected lifetime in mammals, increasing accidents and increasing night disturbances, especially in the elderly. A properly designed circadian lighting system supports both the visual the non-visual needs of the eye in the day and in the night, and is energy efficient.
Research* also shows that there is also a very strong correlation degree of circadian disruption and severity of dementia. Other research has called for good availability of daylight for patients suffering from dementia allied with dark sleeping conditions. Patients with dementia have been shown to have disturbed sleep/wake rhythms that don’t follow the regular 24-hour cycle, or circadian rhythm, that you would see with a healthy older adult which demonstrates the need for circadian lighting in healthcare environments and particularly those suffering from dementia.
The spectrum and intensity of light entrains our “circadian rhythm”, positively affecting our bodies and minds throughout every day. Humans evolved under natural, changing daylight and the development in LED technology means that circadian lighting is now accessible, whilst wireless control options make it affordable and practical.
*Visit http://tinyurl.com/circadianlighting for studies.