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Light = Caffeine? – Put the kettle on and see if you agree!

I’m often asked whether Human-Centric lighting is just healthwash and marketing hype?

To quote Houser, Boyce, Zeitzer & Herf – Human-centric lighting: Myth, magic or metaphor? human-centric lighting has sound motivations, despite being tainted by misleading marketing claims… they prefer the term Integrative lighting and stress that good lighting is not a product, it’s a solution led by an integrated team – starting with design. 

When it comes to the non-visual effects (body clock, alerting and mood effects among others), timing counts too. 

I often use coffee as a familiar metaphor for light – the the average American will brew three cups every day according to Joe’s garage – AMERICANS DRINK 400 MILLION COFFEE CUPS A DAY – worldwide we’ll drink around 400,000,000,000 cups of coffee this year – The coffee drinking experience: Product extrinsic (atmospheric) influences on taste and choice

So is light a bit like coffee?

Grab a brew and  see if you agree!


Bright light is coffee for the brain…

  1. Bright light has a hotline to the alerting centres in the brain – it’s as good as a cup of coffee to beat the post-lunch dip – Does Bright Light Counteract the Post-lunch Dip in Subjective States and Cognitive Performance Among Undergraduate Students?
  2. 30 minutes of bright light during break times boosted alertness on the night shift in a truck factory – and even improved sleep when the team got home – Suppression of sleepiness and melatonin by bright light exposure during breaks in night work
  3.  For those who want to sleep at might, low light levels in the evening will help – four hours before bed (3 lux) shifted ‘dim light melatonin onset’ (the ‘darkness hormone’) by over an hour in just one week-  compared to average room lighting (around 65 lux) – Home Lighting Before Usual Bedtime Impacts Circadian Timing: A Field Study
  4. We’re all different – people chill with an after-dinner expresso- while others are wired if they sip a latte after noon – there’s a 50-fold difference in melatonin response to light after dark between healthy adults of the same age – High sensitivity and interindividual variability in the response of the human circadian system to evening light


But just night under 100 lux (an overhead light) can increase nighttime heart rate, heart rate variability and next-morning insulin resistance – Light exposure during sleep impairs cardiometabolic function

Some people find that a dawn simulator lamp helps them to wake up feeling refreshed too – this podcast is one of my favourite myth-busting listens – Wake Up Lights & SAD Lamps


Light, like coffee, is personal taste and values

  1. Adjusting the light to suit your mood and the task in hand is like getting your coffee ‘just right’ –  boosts employee motivation – Lighting quality and office work: two field simulation experiments, cuts errors and even reduces back pain by up to 53% – Musculoskeletal, visual and psychosocial stress in VDU operators after moving to an ergonomically designed office landscape
  2. You may be one – around half of us – who love loads of light bouncing from the ceiling. The rest are happier in a cave! Putting the ceiling center stage – The impact of direct/indirect lighting on room appraisal
  3. Personal control can cut the electricity bill by 25-30% put the savings towards fancy single-estate beans?
  4. You probably buy fair-trade coffee when you can – costs a bit more but it’s a sign of your values and an investment in the future. TM-66B-Corp and Recolight here in the UK will help you to demonstrate your ethical credentials
  5. The Harvard Business Review offers some great tips to cross the ‘intention-action’ gap – 65% people say they want to go green but only 26% will pay more – The Elusive Green Consumer


Artificial light and artificial coffee? Your brain is more picky than you think

We’re remarkably tolerant, especially when we don’t have any choice. And yet, when you’ve tasted great coffee – or great lighting – it’s hard to go back!

  1. An LED solution that delivers a ‘natural’ balance of wavelengths – close to the visible spectrum of daylight improves visual comfort, daytime alertness, mood and sleep intensity – Effect of daylight LED on visual comfort, melatonin, mood, waking performance and sleep. Perhaps the difference between unbranded instant and a single-estate cold-pressed brew.
  2. Intensity matters as much as brightness – like the difference between an expresso and a long iced latte, distribution can create drama or calm – and even trigger ‘spatial anxiety (Light Distribution and Perceived Spaciousness: Light Patterns in Scale Modelswhile a broadly even distribution of light and dark feels more ‘natural’ and comfortable to most of us and can even make a room feel bigger – Preference for luminance histogram regularities in natural scenes
  3. Your non-visual system is like a caffeine or calorie counter that adds up the units over a day to create your ‘photic’ diet of light – 6.5 hours of bright light (569 lux) – like sitting close to a window during an average day is enough to counteract the effects of blue light from reading on a screen in bed – The human circadian system adapts to prior photic history – although the real problem is not the light from screen – it’s the fact that you’re not going to sleep!


And to take this weeks’ analogy to a geeky extreme, those who love coffee might enjoy this brilliantly geeky article about the benefits of the most widely-consumed psychoactive drug in the world and how treatment and storage affects taste and quality over time. Perhaps unsurprisingly, beans that are stored naturally have better taste and higher quality than those that have been washed – Comparison of chemical compounds and their influence on the taste of coffee depending on green beans storage conditions

And next time you head to your local coffee shop or decide to go the extra mile for a better experience, take a look at the lights Tasting atmospherics: Taste associations with colour parameters of coffee shop interiors (you may find the coffee sweeter in a lighter and red-toned space or sharper and more bitter in a darker and green-based decor). The packaging will have a similar effect on your preferences too (Colour and shape of design elements of the packaging labels influence consumer expectations and hedonic judgments of specialty coffee)!


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