Lighting has a biological and psychological impact on the physical and mental health of humans. To understand this better, let’s first turn to nature. Sunlight, contrary to popular misconceptions, is not yellow. It’s blue. The purpose of blue sunlight arriving in the morning is to signal our body to wake up by halting the secretion of melatonin, the hormone that helps us sleep. The purpose of daylight is to enable us to rise and get on with our day with agility and alertness. It does so by triggering physiological changes in our body, like a rise in blood pressure and a surge of cortisol, which is a natural steroid.
Pic courtesy: Daniele Levis Pelusi
So, if sunlight is blue, what is warm? Fire! Used by our ancestors for warmth, light, cooking and safety, it also marked the end of a day… Phew! After all that hunting and gathering! It signified a period of warmth, relaxation, food, nourishment, togetherness and perhaps, a sense of community. After hundreds of thousands of years, we may no longer light fires every night, but warm, yellow light continues to create a feeling of emotional comfort and relaxation.
Nature created a beautiful, harmonious, and perfect balance between the earth's natural light and dark cycles and our bodily rhythms. But the invention and evolution of artificial lighting especially the blue/ white lights have shaken that balance by disrupting our circadian rhythm, which is our body’s internal clock. Exposure to these lights can impact our sleep, cognitive abilities, feelings of happiness, sadness, anger, other emotions, sex drive, behaviour, stress responses and overall wellbeing.
This is the same blue light that is also emitted by electronic devices like cell phones, laptops and TVs. It suppresses our melatonin (a natural hormone that tells our body when it’s time to sleep) levels, making us stay awake and alert, which is why it’s best to keep our last waking hour device-free. In fact, our brain cells are so sensitive to blue light that they can even impact the sleep patterns of the blind or visually impaired. So, try to keep the lighting in your relaxation spaces, especially the bedroom, warm, amber or red as it helps you relax and unwind, and increases melatonin levels, helping your body get ready for sleep.
Remember, the right lighting can decrease depression and increase cognitive performance by improving our memory, thinking, reasoning and reaction abilities.
Here’s a simple lighting rule that works well for our overall wellbeing. Follow nature’s rhythms! If you must use blue/ white light, then restrict it to workspaces, impersonal spaces, or areas where you need to be alert, focused and efficient. Plus, try and keep these on during the daylight hours only. Post sunset, shift to the eternal fuzziness, charm and romance of warm lighting. It’s good for your body, brain, heart and soul.
Personally, I find it a total bummer to sit in spaces with white/blue light, and have often asked hotel staff to change white bulbs to warm in my room, or give me candles! I have also only gone grudgingly to restaurants with white lighting, for quick in-and-out type meals. And I'm not pleased that many flights have changed their reading lights to white. Finally, if you you think of some of the most aesthetically pleasing, emotionally evocative places you have visited post dusk, or seen pictures of, chances are they've all had warm lighting. And that's no coincidence.