Circadian Lighting

Studies have shown that use of dynamic circadian lighting can improve health, well-being, human performance, rest and sleep. Changing light is the primary trigger for keeping our circadian rhythms on track. You know that good lighting makes you feel better and a sunny day is so much nicer than a grey day. You may know how unpleasant circadian disruption feels, you just probably called it jet lag. 

Halcyon Lighting, Circadian Rhythm Lighting Solution
Humans, like other animals evolved to function in an environment that has a dark/light cycle. In daylight we are active, productive, we eat and we are very alert. In darkness, we sleep, breathe slowly, our heartbeat slows and our core temperature cools. Our modern lives however, require that we use light to see during nature’s dark period, or we live in places where there are less hours of daylight than we evolved to function well in.

Your eyes have a number of cells that respond to light – rods (for low light vision) and cones (for seeing colour in higher levels of light). These connect to your visual cortex in your brain and enable you to see. Other light sensitive cells called iPRCGs connect to your Suprachiasmatic Nucleus, or more simply your central body clock; additionally they influence the release and suppression of many hormones depending if it is dark or light.

Halcyon circadian lighting mimics natural daylight in the day and creates 'biological darkness' at night by changing the colour and spectrum automatically throughout a 24hr period. During the daytime, halcyon will provide the maximum levels of (circadian blue rich) cool white light that has been optimised to stimulate receptors in your eyes (iPRGCs) that will give a strong signal to your body that it is daytime. This can help not only to boost alertness, but also to keep your body in a solid circadian (day/night sleep/wake) cycle. At night time and in the circadian mode, Halcyon will automatically reduce the light levels and change to a very warm glow that has been optimised spectrally to avoid stimulating your IPRGCs. This will allow you to see well as your rods (in low light) and some of your cones (in greater light levels) are sensitive in this part of the spectrum, but the non visual IPRGCs are not very sensitive at all to these redder colours and so your body clock is being told that it is “dark” in biological terms. Find out more about how the halcyon circadian lighting profiles work here.

Circadian Rhythm Clock - Halcyon Lighting

The benefits of circadian lighting: 

  • Improves sleep 1,4
  • Aids stability of body clock 6 - drives natural eating times and reduces night waking 1
  • Faster recovery times 4,5
  • Energising during the day 6
  • Relaxation at evening/night 1,4,6
  • Promotes healthy activity 4,5
  • Increases productivity 7
  • Improves concentration 7
  • Improves mood & behaviour 6
  • Reduces hyperactivity/ADHD 7
  • Reduces errors and accidents 7
  • Increase in memory 8
  • Faster cognitive processing speed 8
  • Reduces dementia symptoms 2,3
  • Reduces cardiovascular disease 4,5,9
  • Reduces obesity/diabetes 4,5,9
1 Figuieiro and Rea, 2005; Roberts, 2008. 2 Gehrmann, 2005. 3 Torrington, 2006. 4 (Roberts, 2000; Vetch et al., 2004; Cutolo M et al., 2005; Heschong and Roberts, 2009). 5 (Wilson, 1972; Stevens et al., 2007; Rea et al.,2008; Erren and Reiter, 2008; Arendt, 2010). 6 (Santillo et al., 2006; Musio and Santillo, 2009; Gaddy et al., Roberts, 1995; Czeisler et al., 1995). 7 (Schulte 2010). 8 (Helbig 2013). 9 2010 Fonken et al.

Halcyon - Circadian Lighting - Health Benefits

News and articles involving circadian rhythms:

  • 'Design lighting for the body, not just the eyes' - Coverage of a PhotonStar presentation on human centric lighting at Lux Live 2014.
  • Circadian Lighting - Myth or Magic? Video presentation by PhotonStar.
  • A private school in Surrey has become the first in the country to delay morning lessons to accommodate the circadian rhythms of its teenage pupils. Hampton Court House runs lessons from 1.30pm to 7.00pm rather than the standard school hours. Read more about it here.
  • Here's an article on the circadian rhythms of teenagers and why every country needs later secondary school start times.
  • Urban light pollution: Why we're all living with permanent 'mini jet lag'. Features our circadian advisor, Dr Steven Lockley. Read the article here.
  • Are you suffering from social jetlag?
  • What Sleep Deprivation Does to Your Brain - Infographic
  • Researchers find relationship between sleep cycle, cancer incidence. Researchers have found a protein that regulates your circadian rhythm also protects the body from developing sporadic forms of cancer. 
  • Sports coaches seem to be realising the competitive edge that might be gained by working with athletes' circadian rhythm, and that in particular, our light-dark exposure plays an important role. Read the article here.
  • Lack of sleep can have role in obesity and diabetes, study says - BBC Report
  • Children's hospital designs sleep app to improve children's sleep - BBC Report