Light and Sundowning

Our circadian lighting solutions are designed to provide the best lighting for the time of day to help stabilise the body clock and reduce sundowning behaviours. It is well understood that not enough light in the day, and too much light at night contributes to sundowning issues. The challenge with conventional lighting is that the light levels need to be very high in the day to keep the body clock on track which can cause overstimulation or is just impractical. Our biologically optimised lighting provides a strong daytime trigger to the body clock without the need for excessively high light levels in the day. During the night, we may need lights to help with attending to night waking and prevent falls, so darkness, which would be the ideal, is not always a safe or practical option. Our system changes the light colour at night to provide night lighting that is spectrally optimised to keep the body in its darkness period, but provides enough light to see and be safe.

The alzheimers society provide the following guidance on sundowning:


Sometimes a person with dementia will exhibit an increase in certain behaviours in the late afternoon or early evening. For example, people may become more agitated, aggressive or confused. This is often referred to as ‘sundowning’. This pattern may continue for several months and often occurs in those in the moderate to severe stages of dementia. It can be particularly distressing for carers if they are trying to relax or have some quiet time.

Sundowning may be caused by:

  • disturbance to the 24-hour ‘body clock’ that tells our bodies when to sleep, caused by the physical changes to the brain
  • loss of routine at a previously busy time of day
  • too little or disturbed sleep
  • too little or too much light
  • prescribed medication (eg for pain or discomfort) wearing off
  • medications that worsen confusion and agitation
  • excessive or disturbing noise.

Using the term ‘sundowning’ may mean that people attribute out-of-character behaviours to dementia and overlook other factors causing the behaviour, such as someone trying to communicate. It is important to look at and address the potential reasons why someone is behaving out of character.

Sundowning – tips for carers

  • Try to give the person something meaningful to do at this time of day, using past activities as a guide.
  • Plan quiet and relaxing activities for late afternoon/evening.
  • Think about what’s happened during the day. Could the person’s behaviour be a communication of a need such as requiring the toilet, feeling hungry or being in pain?
  • Consider minimising daytime naps and make sure the person gets enough light, especially sunlight.
  • Exercise can be beneficial for helping someone to sleep.
  • Improving the environment can help someone to sleep better, as can reducing intake of caffeine and alcohol in the evening.
  • Keep lighting appropriate – if it’s too dark the person may become distressed as seeing things becomes harder, but if it’s too bright it may cause overstimulation.

Contact our circadian specialists to learn more about using light to alleviate sundowning behaviours.