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World Nature Conservation Day – light and health – the perfect storm (or the perfect match?)
Healthcare accounts for over 4% of global net C02 emissions – bigger than aviation or shipping in the top OECD countries – Healthcare in world’s largest economies ‘accounts for 4%’ of global emissions.
The lighting industry has an even bigger carbon footprint contributing around 5% of global emissions through production and energy in use – City street lighting – Global switch by 2025.
And that’s without counting the harm caused by light pollution to the ecologies around us, from pollination to migration and fertility – How Light Pollution Impacts Wildlife & How You Can Help.
It’s tempting to feel overwhelmed.
But you and I can make a bigger difference than we think.
Switching off when you can (and especially after dark) is the obvious first step – but upgrading to LED technology – around 45% more efficient than fluoresents – will have a far greater impact – Life cycle cost analysis of LED retrofit and luminaire replacements for four-foot T8 troffers, Easy but not effective: Why “turning off the lights” remains a salient energy conserving behaviour in the United States.
Getting the right light at the right time could even reduce how much of that carbon-intensive healthcare support we need too: a room with a view, bright days and dark nights can reduce length of stay, speed recovery from post-traumatic stress and other mental health conditions and even cut medication use – Effect of a light-darkness cycle on the body weight gain of preterm infants admitted to the neonatal intensive care unit, Time spent in outdoor light is associated with mood, sleep, and circadian rhythm-related outcomes: A cross-sectional and longitudinal study in over 400,000 UK Biobank participants, Let there be blue-depleted light: in-patient dark therapy, circadian rhythms and length of stay, The Effect of Sunlight on Postoperative Analgesic Medication Use: A Prospective Study of Patients Undergoing Spinal Surgery.
A win-win-win!
Light is not enough
I’m as passionate as anyone about the mental and physical effects of light. But I’m acutely aware that even the most scientifically-circadian lightbulb can’t do the job alone, especially when it comes to setting the body clock.
This is one of many studies that highlight the need for a systems approach, including the critical contribution of other behavioural and environmental factors, including air quality, thermal comfort and noise, to getting a good night’s sleep – Scoping review of the measurement of care environment factors that impact sleep in the rehabilitation, subacute, and aged care settings.
‘Smart’ environmental controls and related features like occupancy monitoring and access control are standard in offices. But despite obvious benefits in terms of physical and mental health outcomes, staff engagement and compliance, a cluster of smart technologies, grouped under the broad term ‘Smart Home Health Technologies, ’ face barriers to adoption in the residential care sector – Benefits and barriers associated with the use of smart home health technologies in the care of older persons: a systematic review.
So I’m excited to work with Helen Glasspool at the National Care Forum and Sean Harvey at St Monica team, John Bullock, Lally Widelska and Ravi Lakhani and technical partners at Commercial Lighting Systems, Casambi and Baulogic to pilot a systems approach to smart circadian-aware supported living.
We’ll be installing the trial in September – more soon!
TWAT?
If you’re working from home today, make sure you get outside.
If may be sunny out there, but, according to this small study, your home-office set-up may not deliver the light you need to set your body clock and keep you awake.
Simply adding a good-quality task light improved subjective alertness and performance on a vigilance task, with improved mood after six hours – Light exposure in home-based work: Can a simple lighting system increase alertness?
Getting through your inbox a bit faster may not be a big deal. But adding task lights to a nursing station can cut the risk of harmful medical errors – The Effect of Blue-Enriched Lighting on Medical Error Rate in a University Hospital ICU.
Summer yellow on sunflower day
The bright yellow sunflowers on my allotment always make me smile, although tinged with sadness as a vibrant reminder of the ongoing conflict in Ukraine.
Humans identify four ‘unique’ hues, blue, green, red and yellow. Our perception of ‘unique green’ changes with age, due to changes in spectral sensivity in the eye: when you ask young and older people to choose ‘unique green’ from a range, the set point shifts to shorter wavelengths over time.
But unique yellow seems to buck the trend, remaining stable across the lifespan. This may be because this tone is an artefact of the visual system, sitting at the ‘null point’ of the colour opponency system – the red and green channels cancel each other out.
This null point quality may also be an underlying reason for the a subtle shift with the season: we shift to a ‘bluer’ version in summer compared to winter because, in the absence of a direct channel input, we are more likely to peg our perception on contextual or environmental cues. As our visual system adapts to more green in the summer, the benchmark shifts to shorter wavelengths – Human colour perception changes between seasons.
This adaptive process starts early, with babies as young as four months old already primed to extract the critical chromatic qualities of a scene – Colour vision is aligned with natural scene statistics at 4 months of age. Another reason to make sure that small children – and older adults- enjoy a vibrant diet of colour all year round.