Sundowning or dusking – time to rethink the twilight zone?
Sundowning, the distress and agitation that affects two-thirds of people living with dementia as day turns to night, is a daily source of anxiety for millions of carers. It is one of the major reasons for the decision to place a person in residential care – Sundowning Syndrome in Dementia: Mechanisms, Diagnosis, and Treatment.
There’s growing evidence of shared neural pathways between those involved in sleep and circadian function and those that modulate aggressive behaviour, agitation and depression in people living with Alzheimer’s disease and related dementias – Potential Pathways for Circadian Dysfunction and Sundowning-Related Behavioral Aggression in Alzheimer’s Disease and Related Dementias.
So it’s perhaps unsurprising that the right light at the right time can help by setting the body clock, creating a virtuous cycle through improved quality and quantity of sleep – Light, sleep-wake rhythm, and behavioural and psychological symptoms of dementia in care home patients: Revisiting the sundowning syndrome.
Bright light first thing in the morning is well-established as a critical time-keeping cue – Morning light exposure: a potential modifier of cardiovascular risk factor, along with reduced light levels in the evening and darkness at night.
But what about the dawn and dusk transitions?
After all, we evolved to respond to the exponential rise – and exponential fall – in light levels at these turning points in the circadian cycle.
There’s some evidence that ‘dawn simulators’, artificial light that mimic sunrise through a progressive change in light levels over 30 minutes or so, can improve the wake-up experience, with a ripple effect on mood, well-being and quality of life, both for adolescents and older people living with dementia alike – Effects of dawn simulation on attentional performance in adolescents, Effects of a dawn-dusk simulation on circadian rest-activity cycles, sleep, mood and well-being in dementia patients. Perhaps it’s not surprising that opening the curtains before the alarm goes off has a similar effect. This study with university students found that motorised curtains, timed to open 20 minutes before wake time, significantly improved the waking process and how quickly they felt alert. This was better than opening the curtains from sunrise (too long before wake time) or leaving the curtains closed altogether (no natural light) – Natural light control to improve awakening quality.
But, prompted by this excellent article in the Guardian (thank you, John Bullock), I’ve been looking at research into the importance of ‘dusking’, or progressively dimming the lights in the evening, as the essential flip side of the coin – ‘All you need is a chair and a view’: could daily ‘dusking’ make us healthier and happier?
As Myriam Aries points out in her recent literature review, it’s much harder to study twilight light exposure: not only do daily mealtimes or caring routines cut across those critical hours, especially in winter, but, unlike the transition from darkness into daylight, the baseline varies so widely – The importance of residential dusk and dawn light exposure for sleep quality, health, and well-being. For example, the average home is bright enough in the evening to disrupt the body clock of 50% of inhabitants, a statistic borne out by my observations in most residential care settings – Impacts of home lighting on human health.
The studies I’ve found so far suggest that, although a twilight routine may be harder to implement, particularly for community-dwelling adults, it may be worth the effort, especially for those who struggle to nod off – Influence of artificial dusk on sleep, Assessing the Feasibility and Efficacy of Pre-Sleep Dim Light Therapy for Adults with Insomnia: A Pilot Study. This is backed up with anecdotal evidence from care homes and hospitals such as WCS Care in the UK – Lighting the way: how circadian lighting is transforming care at WCS, and Syréngården and Ljungbygården in Sweden – Circadian Lighting Helps Residents Wake Up Naturally at Dementia Home.
Perhaps it’s time to shift our perspective from ‘sundowning’ to ‘dusking’ – and harness the power of light to make that transition a comfortable and easy one.
Sites of knowledge production
Knowledge work, a term coined by the management consultant Peter Druker in 1959, in his book Landmarks of Tomorrow. He described the transition from ‘blue collar’ work, where wealth was produced by making stuff, to a new era of white collar work, making a living from thinking. He argued that, ‘by the 21st century, the most valuable asset to any organisation would be its knowledge worker productivity’.
His article ‘Managing oneself’ in the Harvard Business Review explores the implications for the individual in this new paradigm, pointing out that ‘success in the knowledge economy comes to those who know themselves—their strengths, their values, and how they best perform…
And we will have to stay mentally alert and engaged during a 50-year working life, which means knowing how and when to change the work we do – Managing Oneself.
New insights into the impact of workplace design suggest that we should add a third dimension or ‘where’, to the choices we need to make to manage ourselves and optimise performance.
There is growing evidence that we are more productive and engaged – and take fewer days off – when a workplace is designed with our health and well-being in mind. Noise, thermal comfort, air quality and lighting consistently come top of the list of factors, with personal control as a significant predictor of satisfaction – Personal control and environmental user satisfaction in office buildings: Results of case studies in the Netherlands. The basic principle extend beyond offices, Towards a holistic approach for assessing the impact of IEQ on satisfaction, health, and productivity, to healthcare – Indoor environmental quality (IEQ) in healthcare facilities: A systematic literature review and gap analysis, and education – The Impact of Indoor Environmental Quality (IEQ) in Design Studios on the Comfort and Academic Performance of Architecture Students.
I’m writing this in my local library – a place where I love to work, surrounded by books and journals and all the traditional artefacts of ‘knowledge production’ (and lots of natural light!) But the team here are always finding new ways to bring their archives to life – poetry readings, performances, making workshops and even a seed library.
So it’s a privilege to be part of a team working with King’s College, London at the Appendix Space, part of the Medicine Museum in Copenhagen, next Thursday and Friday (19 and 20 of March) as part of a conference on public engagement with science collections. The event is convened by curators from King’s College, London, the Science Gallery in Bengaluru and the National Museum of Scotland, as well as our hosts from Sund University. Spaces are limited, so please message if you’d like to join.