As human beings we are both driven by natural light and entirely reliant on artificial light. We don’t give it much thought. Whether it is natural sunlight streaming in through windows and skylights at work, or the artificial light of a bedside lamp, lighting your time to read and unwind at night. But research has established that light is responsible for a multitude of systems within our physical bodies (not least the Circadian or sleep/wake rhythm) and for our psychological response to our surroundings. Most artificial light is LED light, which emits a sharp spike of ‘blue light’, as well as a ‘flicker effect’ (1)- but what does this mean for you and the potential impact on your mood?
Circadian rhythm- what is it?
Let’s break it down. Light, specifically the blue content of light, will gently stimulate the production of cortisol in the mornings and suppress the production of melatonin. Sunlight has higher blue content in the mornings, fading through the day to help this rhythm- our circadian rhythm. It is tied to our 24 hour body clock and heavily influenced by natural light and darkness, sending brain signals to alter hormones and body temperature to either keep you awake or draw you to sleep(2). If this natural rhythm is upset – for example by excessive exposure to blue light so that we are producing cortisol (and not melatonin) far into the evening and night – we won’t sleep. And without sleep we are generally not in a great mood. In fact, we are exponentially more open to depression and anxiety and other mood related disorders. And it’s not just these hormones that impact our mood. In fact, hormone imbalance features in virtually every expert’s top 10 mood influencers. So keeping our systems regulated, or at least setting them free to find their natural balance is critical.
Natural light has a balanced spectrum of colour, whereas ordinary LEDs have a sharp rise in ‘blue light’. As you can see in the graphs below, on the left is an ordinary LED, where the red line is the sun light spectrum, and there is a clear increase (or ‘spike’) in blue light. On the right is a graph outlining the colour spectrum within RAY Lighting products, a brand that we stock and sell- more on that later. It is clear that these products are closer to the spectrum of natural sun light, and therefore more efficient in stabilising our natural circadian rhythm. There is hope, as these products are stocked and sold for both domestic and commercial use.
So what is this blue light?
Blue light is part of the visible light spectrum, but has higher energy and shorter wavelengths than other colours (4). This blue light is balanced within the natural sunlight spectrum, but excessive in artificial light- such as ordinary LEDs. Research has found that we now spend around 90% of our time indoors (5), where there is only so much natural light available. LED lights are in most lighting items that we commonly use at work or home- ceiling lights, lamps, smart phones, televisions, computers, kindle and many more. In recent years there has been an increase in encouragement that we should not look at screens just before going to bed, but even reading next to an LED lamp is impacting our mind’s ability to wind down.
Did you know? The UK law states that half of your workplace should be lit by natural light, and more than half of your home should be naturally lit. Surprisingly, these aren’t recent laws based on current medical findings; they have in fact been in place since 1832 when the Prescription Act was instated.
https://www.right-of-light.co.uk/services/calculations-and-reports/
What about the “flicker effect”?
Most people don’t know that almost all LEDs flicker. As the current moves through an LED lightbulb, it flickers at around 100-150 hertz (6). It’s so fast we don’t see with our conscious eye, but it is extreme in most – from full darkness to full light thus deemed 100% flicker. Whilst we have learned not to respond to it, our mind still tries to process it, often resulting in a hyper alert or anxious state, general malaise, and headaches. And that’s the low-level responses.
Research has found that this constant flicker can also stimulate ADHD, ADD, epilepsy and ASD to name a few (7). And it certainly impacts our mood. Ever had that feeling that you’ve been inside too much and then you get outside for a moment and feel so much better? That’s the light!
Natural beauty makes us happy
Another big deal when it comes to lighting is colour. Seeing stunning colour in a full and balanced spectrum is nothing short of magical. It lifts us. In nature we are exposed to the full range, but inside under poor quality light colours can be severely skewed and can seriously impact our behaviour. Bad lighting can make you eat more, or make worse food choices. It can make us feel physically sick. It can change the way our eyesight develops. And not seeing a full range of colours and textures has definitely been found to impact our mood.
Lighting is measured in terms of CRI – Colour Rendering Index – with sunlight rated at 100. If your lightbulbs are rated at anything less than 95 and you’re spending significant time beneath their artificial spectrum, it’s likely you are going to be unconsciously affected by the skew.
So what is the solution?
Aiming to receive as much natural lighting as possible throughout the day can improve our body’s circadian rhythm. A Cornell study found that “workers exposed to natural light experienced an 84 percent drop in issues such as headaches, eyestrain, and blurred vision.” (9). Unfortunately we can’t all live in sunny climates with glass fronted/ceilinged homes and offices- but our choice of lighting design, where it is installed and the lights themselves can help to reduce negative impacts of traditional LED lighting on our mood. For example, a singular white ceiling light in a windowless room may make us feel like we are under a spotlight, whereas several lamps, hanging pendants or wall lights with a warm colour tone may make us feel more comfortable.
Consider where you spend most of your time, and try to choose lights that support your circadian rhythm- balanced lighting with a cooler tone can help to keep us alert without being over stimulating, whereas soft, warm lights are better for winding down or relaxing. The choice of light bulbs specifically will also have a considerable impact- we work with and stock RAY Lighting products (mentioned earlier in the blog), which, using their unique BlueBalance® technology, have reduced intensity of the blue peak, creating a light source that is a human-centric natural solution for the increasingly indoor and screen heavy lives that we lead now.
Need our help? Get in touch with Brightbox for all your office and work space lighting: info@brightboxlighting.co.uk.
References:
1- https://www.waveformlighting.com/human-centric/are-led-lights-safe-are-they-harmful-to-your-health
2- https://www.health.harvard.edu/staying-healthy/blue-light-has-a-dark-side
3- https://ray.lighting
4- https://www.webmd.com/eye-health/what-is-blue-light
5- https://www.opinium.com/brits-spend-90-of-their-time-indoors/
6- https://www.soraa.com/learn/science/how-test-led-flicker-home.php
7- https://jcdr.net/articles/PDF/12880/41491_220419_41491_CE[Ra1]_F(KM)_PF1(AJ_SHU)_PFA(SL)_PN(SL).pdf
8- https://www.activehealth.sg/read/screen-time/what-are-the-negative-side-effects-of-too-much-screen-time
9- https://www.newdayoffice.com/blog/benefits-of-natural-light-in-the-workplace