«The pineal gland, the ancestral receptor of light now connected to the retina and eyes [..] is our main “equipment” that constantly connects us and adapts us to the many variables in the natural earth environment»
During the autumn and winter months, when there are fewer hours of daylight, some people may suffer from a melancholy or depressed state: They feel tired, sad or unmotivated. Our immune defences can be affected too. The changes in light during the year may cause ailments. The presence of light is therefore an essential factor for a person’s well-being.
In the northern hemisphere, in the period from September to March, some people cannot manage to adapt their body’s rhythms to the reduced exposure to daylight.
Some people even lose the notion of time, feel imbalanced and disoriented. Without daylight, we feel stressed and physically unwell. This is what happens to those suffering from SAD
As light changes, hormone levels and those of other chemical compounds that govern circadian rhythms undergo a variation in their cycles.
Many specialists, in fact, believe that SAD symptoms can be traced to a change in circadian rhythms, caused by a biological dysfunction: a reaction to the shortest, darkest days of autumn and winter.
Research on SAD is focusing on the fundamental interaction between light, the endogenous production of melatonin and other variable rhythms that regulate the concentration of chemicals in our bodies.
SAD and the therapeutic role of light
«Most of our organic functions […] follow the circadian rhythm. Controlling these rhythms is largely dependent on the moment when we expose ourselves to light and the duration of this exposure. »
Experts have noted that the further north a zone is (in the northern hemisphere), the higher the incidence of SAD in the population, due to the greater lack of sunlight.
The effect of light on our mood was acknowledged in 1980.
Dr Rosenthal, who was the first person to identify this disorder, saw how people affected by SAD and suffering from depressive episodes, saw their symptoms lessen when exposed to intense light.
Other researchers obtained similar results. Michael Termon, from Columbia University, discovered that a few days’ exposure at 2500 lux for two hours in the morning led to the total disappearance of depression in about half the patients undergoing this type of treatment. He then also evaluated the possibility of prolonging the exposure and increasing the light intensity to achieve better results.
Light affects immunity
Through its ultraviolet radiation, sunlight stimulates the production of vitamin D in the skin that is then transported to the bloodstream together with its metabolites.
The lack of exposure to sunlight, and therefore of this important vitamin, should not be underestimated.
In addition to the known consequences on bone health, recent studies have shown that vitamin D is involved in several processes, such as immune system modulation.
«When circadian rhythms are disturbed, we realise how much nature influences our lives. We feel out of place and lose contact with the rest of the world. It is in these cases that we feel the profound role these natural cycles play in our lives more intensely.»
1.Pierpaoli W., La Chiave della Vita, Morlacchi Editore, Perugia, 2007
2.Bizzaro G, Antico A, Fortunato A, Bizzaro N. Vitamin D and Autoimmune Diseases: Is Vitamin D Receptor (VDR) Polymorphism the Culprit? Isr Med Assoc J. 2017 Jul;19(7):438-443. PMID: 28786260.
3.Kulda V. Metabolizmus vitaminu D [Vitamin D metabolism]. Vnitr Lek. 2012 May;58(5):400-4. Czech. PMID: 22716179