How to feel better when it's still dark outside?

The appropriate amount of sunlight is crucial for the proper functioning not only of the nervous system, but also of the entire body. It is light that stimulates the pineal gland and hypothalamus to secrete the hormones produced there , and their levels, in turn, affect our well-being. Sunlight affects the retina of the eye, which in turn affects the secretion of serotonin (the so-called happiness hormone). Insufficient stimulation with sunlight also disturbs the secretion of norepinephrine . Abnormal levels of these compounds have a huge - negative - impact on mood and well-being .

Additionally, insufficient sunlight causes the pineal gland to produce melatonin , the sleep hormone. The more melatonin, the more tired and sleepy we are . The circadian cycle is disrupted, the biological clock is dysregulated, and the consequences for the entire body are serious. Not only may irritability, concentration problems and headaches occur , but also hormonal disorders may occur .

Light deficiency can cause seasonal depression.

The change of seasons and the deficiency associated with it is closely related to seasonal depression ( SAD ) , i.e. a disorder characterized by a seasonal-recurrent course. It usually appears in late autumn and lasts until spring . The frequency of this disease in the population is closely related to latitude - SAD occurs more often in high latitudes. Statistics show that while in the temperate zone SAD affects approximately 4% of the population , in places where there is a lack of light in autumn and winter, this number increases to 10% . Interestingly, women are four times more likely to suffer from SAD than men, and the risk of developing the disease decreases with age.

As in the classic course of depression, in the case of SAD there is a decrease in serotonin levels and disruptions in the action of norepinephrine, dopamine and melatonin , which in turn is related to vitamin D deficiency. Vitamin D influences the activity of serotonin. When the days are long and sunny, the body produces more vitamin D. The less light, the lower the concentration of vitamin D. The appropriate level of vitamin D has a huge impact on immunity, relieves inflammation, has a positive effect on circulation, reduces the risk of some cancers and prevents rickets. in children ( read more about the properties of vitamin D in a separate article ).

How to prevent the negative effects of sunlight deficiency?

Of course, it is worth spending as much time outdoors as possible to make the most of the few sunny hours that we have in winter in our latitude. Physical activity also plays an important role , so it is worth taking at least short walks outdoors every day . A one- or two-week trip to warm countries to "recharge your batteries" is also a good idea. It is also worth taking care to supplement vitamin D deficiencies in the body.

Another recommended method of replenishing sunlight deficiency is phototherapy , which has been used - also in SAD - since the 1980s. What is it about? It is simply exposure to a special lamp emitting light with an intensity of 2.5 thousand. up to 10 thousand lux. Exposure sessions last, depending on the intensity, from 30 minutes to even two hours. The therapy lasts 2-3 weeks and its aim is to reduce the concentration of melatonin in the body. The best results are achieved by using lamps (popularly called "anti-depressant lamps") in the morning, because they aim to balance the circadian rhythm . There is no need to stare at the lamp. Its light is simply supposed to reach the retina of the eye. Such a lamp can be purchased privately and illuminated at home. The prices of lamps range, depending on the manufacturer, from several hundred zlotys to several thousand.

Bibliography:

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3. Seasonal affective disorder (SAD), Mayo Clinic, accessed December 5, mayoclinic.org.
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5. Radiation: The known health effects of ultraviolet radiation, WHO, 2017. who.org.