After the time change in autumn it gets dark from about 5 o’clock in the afternoon. The lack of light affects the mood of around 20 percent of people in Germany: they suffer from listlessness, an increased need for sleep and ravenous appetite, even depression. Light therapy and outdoor exercise can help.
Sick due to darkness
Due to the onset of the dark season, the cells of the body get out of sync. The human internal clock needs light to synchronize cells and physiological functions with the external time of day.
- There is a lack of messenger substances such as the happiness hormone Serotonin.
- The sleep hormone melatonin is increasingly released.
- A lack of Vitamin D can produce. (A vitamin D preparation from the pharmacy supports the immune system and counteracts the risk of a gradual loss of stability of the bones.)
Exercise and light therapy can help
If you manage to walk for an hour in daylight every day, even in autumn and winter, you will get enough light even on dull days to avoid winter depression.
- Professional Light therapy devices use a daylight spectrum with an intensity of at least 10.000 lux.
- In the case of Walk in the fresh air, the light intensity even on dull winter days is 2.500 lux, which is higher than the 500 to 600 lux indoors.
Use light therapy correctly
Before purchasing a daylight lamp should be advised by an ophthalmologist, because caution is required for some eye diseases. As a rule, treatment in the morning is recommended. It should be used every morning for half an hour to give the start signal to the internal clock.
To do this, sit in front of the lamp with your eyes open and no further than one meter from the light source. During the therapy one can work, read or eat. The first improvements in symptoms are noticeable just a few days after starting therapy. Experience shows that mood brightens within two weeks. The effectiveness of light therapy is scientifically proven.
Full-spectrum light prevents winter depression
So-called full-spectrum lamps can also help against winter depression. They reproduce the entire spectrum of daylight and can be used, for example, in ceilings and table lamps. Because of the longer duration of illumination, the light intensity can be much lower than with light therapy. Initial scientific studies suggest that full-spectrum lighting in the workplace can prevent winter depression.
Causes of winter depression
The human body follows a biological rhythm. Above all, the sleep-wake rhythm is regulated by the incidence of light in the eye.
- Scientists have discovered cells in the eye that produce serotonin via a so-called Photoreceptor for blue light (daylight) have: the protein melanopsin. When blue light hits the cells, they transmit the signal directly to the "inner master clock" (suprachiasmatic nucleus).
- From there, the signal travels through the activation center of the brain and spinal cord to what’s called the hypothalamus, which Hormone release controlled: Blue light reduces the production of the sleep hormone melatonin and stimulates the production of the stimulating hormones cortisol and serotonin.
- Since the Light intensity in winter is lower overall, more melatonin is released not only at night but also during the day.
In people with winter depression, the photoreceptors in the eye are less sensitive to light than in other people. The hormone serotonin is probably also involved in the development of winter depression. It is needed for the production of melatonin. The result: the serotonin level in the blood drops. This also has an influence on mood. The brain tries to compensate for this deficiency by an increased desire for sweets. Sugar and foods like chocolate provide the brain cells with more serotonin again.