It’s no accident that we feel better on a bright sunny day = exposure to sunlight is correlated to our Serotonin levels [Lancet Article]!   Increasing our exposure to sunlight (and/or bright light) during the day is a natural drug-free way to increase our serotonin levels, and improve our mood and overall health [Journal of Psychiatry and Neuroscience].   Most animals and plants are sensitive to the cycles of natural light and rely on the daily light/dark cycle to synchronize their patterns of activity and rest.  In humans, our ‘circadian rhythms’ include the expression of Serotonin during the day and Melatonin at night.  Studies are confirming what many of us know intuitively = light and serotonin make us happy, feel better and sleep easier!


Serotonin is an important neuro-transmitter tied to our state of wakefulness which helps regulate mood, appetite, sleep and overall wellness.  Our feelings of happiness and well-being are correlated to both the daily and seasonal cycles of serotonin.  Research shows that our daily cycle of serotonin is correlated to bright light exposure and can also be influenced by thought patterns, diet and exercise.  Exposure to sunlight and bright light signals our bodies that it is time to be awake and alert, which increases our production of Serotonin.  Seasonal Affective Disorder (SAD) is strongly correlated with reduced exposure to sunlight during the winter months.  The most common antidepressants, called selective serotonin re-uptake inhibitors (SSRIs), are designed to make more Serotonin available.  A recent study suggests that exposure to bright light also reduces non-seasonal depression and can be just as effective as anti-depressants [JAMA article].   Research confirms the strong link between light and serotonin, and our happiness!

Most indoor lighting falls woefully short of providing the ‘awake and alert’ signal we need to feel our best.   Natural light cycles from bright blue-rich light during the day to soft warm light at sunset, as the sun moves from overhead to the horizon.  Lux is a measure of the intensity of light perceived by the human eye.  A bight sunny day provides illumination of >10,000 lux, while even a cloudy day provides >1000 lux.  Sunrise and Sunset are typically ~500 lux, as the atmosphere effectively filters the light from the sun.  Most indoor environments are lit to only 50-100 lux which provides enough light for us to see but falls well short of the light needed to stimulate our ‘awake and alert’ and serotonin cycle.   Studies suggest that >500-1000 lux is needed to provide a robust biological awake signal, so even a brightly lit office (300-500 lux) is generally insufficient.  Without robust bright light exposure during the day, we don’t get the cortisol and serotonin cycle, which underpins our energy and happiness.   Researchers suggest we are now living in a bright-light deprived society, without the light and serotonin we need to feel our best!

Working in a dimly lit office may be impairing your brain function [article]!

A new class of lighting products are now making it possible to bring the benefits of natural light indoors.   Natural light is full-spectrum (contains all the colors of the rainbow) and dynamic (changes color and intensity with the time of day).  Most artificial lights do not contain a natural balance of colors or provide the dynamic range (brightness and color) of natural light [blog post].  It’s no accident that fluorescent and LED lighting feels unnatural = it doesn’t support our circadian rhythm or contain all the colors of natural light.   Light therapy boxes are proven to help mitigate depression by providing extra bright blue-rich light, but they require you to sit next to them for a ‘dose’ of bright light each morning – and aren’t safe to use in the afternoon or at night.

The good news is that a new class of ‘human centric’ lighting products can bring the full cycle of natural light into your home and office.  These lights change intensity and color with the time of day, to support our circadian rhythms, and can be used like regular lights.  During the day they provide the bright blue-rich light which stimulates us and makes us feel happy.  In the evening they provide soft warm light which naturally relaxes us and prepares us for sleep.  Sunlight Inside is the first company to produce lamps which automatically deliver the daily and seasonal cycles of natural light [click here for more info].  The light from Sunlight Inside products is the closest you can get to natural light – don’t settle for artificial light, enjoy  the perfect natural light at every time of day!