Many people nowadays suffer from a seasonal winter depression, which we do know is strongly linked to the lack of light we are receiving in the short winter days. Mayo Clinic defined this symptom as a sub-type of depression that is linked to the change in season. We do call this symptom SAD, which means “seasonal affective disorder”. If we receive less hours of sunlight, our hypothalamus cannot perform correctly. The hypothalamus is the part of the brain, which controls the circadian rhythm and if the circadian rhythm is disturbed our melatonin and serotonin hormones, which affect our sleep and our mood are out of balance.
This means in winter, when we have to less light, our body overproduces the sleeping hormone melatonin and therefore causes sleepiness. The disturbed circadian cycle can then lead the serotonin, which plays an important role in our mood, to quickly be removed from the space between neurons. This is caused by an overload of transporter proteins and causes the chemical to be shifted back into the presynaptic neuron, which then can lead to depression. But not only with the lack of light in winter but also by us “consuming” too much of the “wrong light”, especially at the “wrong time” can disturb our circadian cycle. Blue Light is a very good example of this and is especially found in TVs, Screens and Phones. It has a very high amount of LUX (Intensity of Light) which can significantly disturb our melatonin level in the evening and makes it harder for us to fall asleep.
If we want to find a way to improve our wellbeing and mood, with the correct lighting, then we first need to know the two measures of light, which influence our body. On the one side there is the just mentioned Intensity of Light (LUX) and on the other side, the color temperature of the light, which is measured in Kelvin. Warm light will make us feel more relaxed and creates a very welcoming atmosphere, whilst cool light in contrary increases our productivity level and makes us feel more focused. In fact we can control our workflow or mood of feeling relaxed and cozy with the correct light setting.
But how can we help ourselves in winter, when our body literally “lacks of light”?
What scientists advise on is to try on simulating natural daylight cycles with artificial lights. Brighter and stronger light is recommended for the morning and during the day, while dimmable light is suggested for the night. Besides one of the most effective ways to treat SAD is using a “light therapy box”, which is also known as phototherapy. It is based on the idea, that if the lack of sunlight contributes to SAD than an adequate dose of light can reverse the symptoms. Important is that the light box produces a very high number of LUX - recommended are 10.000 LUX, which is about 20 times brighter than the usual indoor lighting. The best is to perform light therapy every day at the same time, preferably in the morning. By sitting in front of the lightbox for 30-minutes, the photosensitive retinal ganglion cells in the eye will start stimulating and activate the hypothalamus. The daily activation of the hypothalamus at a certain time controls the release of hormones and restores a normal circadian rhythm, which then will eliminate the seasonal symptoms.
It might sound a little bit strange for us that sitting in front of a lightbox might help us through the seasonal winter depression but there is a study, which has been published in the American Journal of Psychiatry, that shows, that lamps with a dose of 10.000 LUX can effectively treat SAD after only one week of use.
Another approach, which researches are currently studying, is the idea of simulating the dawn. This can be done by a lamp, which is controlled by a computerized timer, that gradually increases the light intensity from 0 to 300 lux. This way we can simulate the natural sunrise and allow our body to slowly wake up, the same as we do naturally in summer.