WRITTEN BY TARJA JOKINIEMI
Tarja Jokiniemi works as a Marketing Manager for solutions and services at Helvar. She is a vision-oriented marketing, communications and branding professional with strong expertise in developing and executing B2B launch strategies and content creation to promote thought leadership and solutions benefits. She has 30 years of experience in business development, conceptualising and marketing in technology, lighting, design and public sectors. She holds an MBA degree from Henley Business School, part of the University of Reading.
We Finns, like so many people in the Northern latitudes, live in a harsh environment where the sun is visible only a couple of hours per day – if at all – during the winter months. The low angle of the sun in the northern winter sky further reduces the reception of bright blue light. This makes us Northerners appreciate good lighting and well-illuminated places. It also makes our country a natural testing ground for lighting innovations, in the same way that tyre manufacturers test their winter tyres here. We certainly walk the talk – we Finns have even a special word ‘kaamos’ for describing the dark sunless period of the year.
Lighting lifts our mood and makes us feel more energetic and happier
As many studies show, light affects complex systems that govern the 24-hour circadian clock in the brain, which regulates not just our sleep-wake cycles, but also hormonal activity, digestion, and other important bodily functions. Lighting has a direct impact on our brain and our hormone balance via the retina in our eyes, even for blind people.
If we don’t receive enough light, the happiness neurotransmitter serotonin isn’t released to the same extent. While this can be just a transitory case of the winter blues (with cravings for sweets or a temporary disruption in our sleep schedule), for some it’s a sign of seasonal affective disorder (abbreviated SAD) with symptoms similar to depression (such as feeling sad, listless, sluggish, or having difficulties concentrating). Studies suggest that 20% of us might experience a mild version of the winter blues, while 1-5% might be suffering from SAD due to the shortening in day length and lower light intensity.
Pay attention to Zeitgebers — the timekeepers of our circadian rhythm
Zeitgebers are cues – cyclic or recurring patterns such as light-dark or warm-cold – given by the environment that reset our circadian rhythm  and keep organisms functioning on a regular schedule throughout the day and night. And, the most potent cue of all is light.
Our mood and energy depend upon getting sufficient bright light and enough contrast between the morning’s bright, intense blue light and the evening’s delicate warm hues to signal ‘awake and alert’ as well as ‘tired and sleepy’. Without these signals, our bodies can’t clearly distinguish between night and day, and don’t provide the energy and hormones we need to feel at our best and to resile from the day’s stress. The key point here is that circadian rhythms are not driven by an external cycle, but instead are generated internally and then synchronised to the external 24-hour world with the Zeitgebers.
A critical part of the circadian rhythm is the brightness of our surroundings. Seeing too little light in the mornings, or too much light in the evenings, or receiving the wrong colour of light at the wrong time of the day, can upset our circadian rhythms and impact health and wellbeing, even increasing the risk of several diseases . In the mornings, many of us are already using bright light devices (10,000 lux, 4000 Kelvin) at home when eating breakfast and getting ready for the winter day ahead. This is great, but as we spend most of our time at work or in places other than our homes, these places should also support our wellbeing better. Let’s explore why workplace lighting is the key.
Why do light intensity, colour temperature and contrast matter so much?
The winter’s greyer skies, shorter days, and lack of sunshine and natural bright, blue light affects us both in the outdoors and indoors. During the winter months, people leave their homes in the dark and then commute home again, in the dark. If they also spend all day in a workplace without enough bright light, it can affect most people’s dispositions. In more recent years, we’ve also adapted to spending almost 90% of our time indoors . This lifestyle change means that we typically spend less time in natural light, so this has a huge impact on our circadian rhythms.
Light intensity can be measured with lux (lx) — a unit measuring the intensity of light hitting a surface. One lux is one lumen per square meter.
Ideally, to keep or reset our circadian rhythm, we would receive lots of natural, bright blue-enriched light at the right time of the morning. The open sky’s light intensities range between 10 000 and even greater than 100 000 lux with 4000-6500 Kelvin (pure white to bright blue colour temperatures). That’s a lot of light that we should be able to enjoy every day!
The darkness of the somber period is accentuated at the winter solstice, on 22nd December, when the daylight hours are at their shortest in the annual cycle. The weather conditions have a major influence on the amount of light at the winter solstice. Snow, especially dry and pure snow, reflects light effectively, increasing the amount of light.
Now let’s think about us Finns again, in mid-winter’s urban conditions without snow and on a cloudy day, we barely get 100-500 lx even in the brightest hours. And the lighting levels in an average working area can be a flat, marginal 300-500 lx at a warm 2700 Kelvin colour temperature.
An example of an average winter day’s light levels in Helsinki during working hours.
Simply put, this light level described does not add up to enough bright light and contrasting lighting conditions during the working day. We should prioritise getting enough bright blue light in the morning to generate more contrast and provide a stronger Zeitgeber cue. This contrast can help to stabilise our circadian rhythm improving health, sleep and cognitive performance.
Get 10,000 lux of blue bright light in the mornings. Boost your activity and energy with bursts of cool light followed by warm dimmed light sequences during the day times. Try to get enough contrast in lighting conditions between morning and evening. Decrease the lighting levels towards the evenings with warm hues of yellows and oranges.
In the Helvar 100 — Discovering Brighter Spaces Event, Performance Scientist, James Hewitt, shared his findings on good lighting and circadian rhythms: «Inconsistent light-dark cycles related to our lifestyles mean that we are gradually falling more and more out of sync with our environment. In fact, in industrialised societies, our body clocks are becoming more delayed. We feel like it’s earlier relative to the earth’s day-night cycle, which means that it’s more challenging to wake up in the morning and harder to get to sleep at night. This delay might be explained by weaker Zeitgeber time cues related to a smaller contrast between light and dark in our environment.» 
For many of us, the winter blues equal problems with sleeping – either feeling tired all the time, struggling to fall asleep in the evenings and thus not sleeping enough or not getting enough quality sleep. Spending most of our time in the constructed environment with fixed lighting and smaller light contrast during working hours, as well as the increased blue light exposure after sunset (mobiles, screens , educes slowing down our personal circadian clock further. Some studies indicate that if we were to look at an electronic device within two hours of going to bed that suppresses our melatonin production. We send a signal that it’s daytime at the wrong time. Ideally, it should be dark, the light intensity should be decreasing, and ideally, the colours that we get exposed to should shift from blue and rich white light to more oranges and yellows.
The benefits of intelligent, human-centric lighting in the workplaces
Fixed, traditional lighting isn’t designed to support our wellbeing. It lacks the ability to tune lighting levels throughout the day as optimal lighting conditions would also require variation in hues and intensity. Modern human-centric lighting controls, however, offer dynamic lighting features including brightness and colour temperature controls. By incorporating these dynamic features in a workplace, a human-centric lighting system more accurately emulates natural light, therefore supporting the circadian rhythms of everyone using the space .
Three examples of different Circadian Rhythms. Intelligent human-centric lighting can change dynamically colour temperatures, light level brightness and rhythm to emulate natural light during the day.
As discovered, fixed 300-500 lux level lighting in the workplace will not help us to feel more energetic and perform at our best, nor it will support our wellbeing and health. The lighting at our workplace should give us what our body-clock needs – better quality light during the darker winter days to counter all the effects causing winter blues or SAD. Our indoor lighting should optimally resemble a summer day — lots of bright light and occasional changes of light levels similar to shadows from drifting clouds in the sky ending with a beautiful sunset. What a happy vision!
Luckily, lighting is one of the easiest renovations to accomplish, and modern lighting will also save energy. When I walk into my workplace lobby in the morning, I feel bathed in light — not a bad way to start the day!
There are huge benefits to be gained by improving workplace lighting, as our experts can tell you.
• The most potent Zeitgeber of all is light.
• The contrast, colour temperatures and effective spectrum in light are keys to our circadian rhythm.
• People spend almost 90% of their time indoors without natural light.
• Artificial lighting should have variability, fixed lighting is outdated.
• The workplace’s human-centric lighting is the easiest way to support employees’ wellbeing, performance, and circadian rhythm.
• Workplaces could have light corners in their break and rest areas where the amount of light could be at a therapeutic level.
• There are huge benefits with intelligent lighting controls and human-centric lighting to be gained in all kinds of places ranging from e.g. offices, schools, elderly people’s homes, hospitals and factories.