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Light on human (and our pets)

This week I wanted to share a selection of old favourites and a couple of papers about the environmental impact - from our need for daylight to how light pollution is harming the world beneath the waves down here on my beloved Dorset coast - and on your canine companion!

 

This is a classic review article from Leukos setting out the 'known knowns' and the known unknowns - and some practical solutions for professionals. Worth a read for anyone who works with light. - A Review of Human Physiological Responses to Light: Implications for the Development of Integrative Lighting Solutions

 

Two factors influence the rise in melatonin levels: bed time and evening light exposure. Bedtime explained 37.3% of the variance in the timing of the rise in melatonin levels - and evening light exposure accounted for an additional 13.3% of the variance. - Bedtime and evening light exposure influence circadian timing in preschool-age children: A field study

 

Just 100 lux in the evening gives half the phase delay (the shift in timing of the body clock) as 9,000... - Sensitivity of the human circadian pacemaker to nocturnal light: melatonin phase resetting and suppression

 

This excellent review explains how, as LED lighting reach 'peak efficiency' at around 200 lumens per watt, the real savings - estimated between 5-30% - can be made in human behaviour - simply encouraging us to use that precious resource when and where we need it. - Improving lighting energy efficiency through user response


Daylight is obviously the most natural and sustainable light source of all. And yet, as this report points out, there are massive blind spots in our understanding of how much we actually need (and if we can have too much of a good thing), how we measure it (and which factors make a difference) and a lack of joined-up thinking between architects and planners, clinicians and occupational health practitioners, specifier and manufacturer. It concludes: 'Access to natural daylight is nowadays unfortunately not considered as an explicit aim by leading institutions worldwide, such as, for example, the WHO, where the “Healthy Cities” concept... although it mentions access to green spaces, does not explicitly require access to daylight. Accessibility to daylight should be part of global discussions about sustainable living, health and well-being, and should be included in the UN 2030 Agenda for Sustainable Development and the WHO’s “health for all” policy - The Role of Daylight for Humans: Gaps in Current Knowledge

 

I am lucky enough to swim in the sea every day. This article explains how light pollution is harming the fragile marine ecology too. -  Biologically important artificial light at night on the seafloor

 

Your pooch has a body clock too - and, although it's not exactly like yours (after all they are closely related to foxes and wolves who are partly nocturnal), it is sensitive to the day-night cycle. And sleep does help them to stay happy and healthy too! -  Sleep in the dog: comparative, behavioral and translational relevance