Circadian lighting: lighting that improves your health

When choosing a house, we all want light, lots of light. Somehow, we sense that the sun is going to do us good.

But what happens in our bodies if we spend a lot of time in places without sunlight? What is the best artificial light for working? What are the effects of not using the right bulb?

If your eyes get tired and you return from work with migraines, you may need to learn what circadian lighting can do for you.

Your body moves to the rhythm of light

Human beings are creatures of habit. Seemingly small changes in the outside world can trigger all kinds of changes inside our body. A good example are the two time changes we make every year (which will disappear). Something seemingly as trivial as moving the clocks forward or back by an hour causes sleep problems in a significant percentage of the population every year.

Most of us have accustomed our body to be active during the day and to sleep at night. As a result, our cells use sunlight to orientate themselves and accelerate or slow down their metabolism. Circadian Rhythms are the set of mental, physical and behavioural changes that we experience during 24 hours.

In contemporary Western civilisation, humans spend most of their lives indoors, under a roof, with artificial light. How does this affect our circadian rhythms?

It is logical to think that our metabolism can be affected if we barely see sunlight. In recent decades, scientists have been engaged in investigating circadian lighting, which consists of simulating the biological rhythms of the human body. Their findings include the relationship between altered circadian rhythms and the development of eating disorders, insomnia and depression.

How is this achieved? If we didn't spend so long indoors and lived in climates and homes with an abundance of sunlight, we would wake up with a light that would progressively, hour by hour, increase its intensity and transform into a warm light at noon. Then, also gradually, it would decline until nightfall.

Following this logic, it is easy to trace 5 principles of circadian lighting:

• Cool lights under which you work and warm lights under which you relax: historically, working hours were during the coolest hours. In the early hours of the morning the sunlight is cold, but it becomes warm as the day progresses. Cool lights are therefore recommended for reading, working and concentrating. Warm lights are contraindicated for all the above but transmit relaxation and tranquillity.
• Intensity controllers: these simple devices are cheap and allow you to regulate the intensity of the bulb in each room. They are highly recommended in places with little sunlight, as there is no better way to imitate the day, with a peak of light at midday that declines both before and after.
• In the bedroom, yellow/orange and soft lighting: this imitates the sun at dawn and sunset. Being the ideal room for resting, it is where we most need a dream-prone atmosphere.
• No screens before sleeping: screens reflect light and, in doing so, activate the brain. Reading a book in paper format is a much more advisable activity for promoting sleep.
• At night, sleep: except for exceptional occasions, what is good for your health is to go to sleep at night. Obviously, this is not always possible (especially when the days are short) but it is an ideal goal to progress towards.

The best light for your work

In addition to our own home, the workplace is usually the place we spend the most time. That's why setting up optimal lighting has undoubted effects on our concentration and productivity.

But it's not just about working more and better. It is also about our health. Eye discomfort and visual fatigue, which are common in the work environment, are very often related to the type of lighting. Even back and neck ailments may be caused by inadequate light.

Follow these 5 tips to ensure healthy lighting in your workplace:

• Mostly cool lights: that is, bluish lights. These promote concentration.
• Avoid screen reflections: take your time each morning to orientate the screen so that there are no portions of the monitor that will bother you with flashes. Reflections cause a loss of concentration and generate visual fatigue in a short period of time.
• Avoid sudden changes in light, flashing lights and contrasts: you are advised to maintain the same level and tone of light throughout the working day, unless, during the same day, we change to a completely different task (and if we do, it is advisable not to make many changes in a short period of time). Moving from a gloomy to a strongly lit environment, or vice versa, causes disorientation and affects our circadian rhythms.
• Avoid low and too dim lighting: this forces you to strain your eyesight, immediately provoking tiredness, headaches and stress.
• Seek sunlight: all you can get will do you good, as it offers your body clues about the time of day we are at, adjusting all your rhythms. A place beside the window is always the most desired.