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Despite all the negative consequences of contact with solar radiation, among us there are no indifferent to the heat of the star. From a biological point of view, we are diurnal creatures and are directly dependent on the sun. Its light allows us to navigate in space and get aesthetic pleasure from the shapes and colors of the world around us.
The Egyptians, Mayans, Incas – ancient civilizations revered the sun as the giver of all blessings. The famous Sphinx was erected as the incarnation of the god Ra, the Sun-Creator. In Greece, on Rhodes, and in Rome, the solar god Helios was honored. Each ancient monument, which had a cult purpose, was built in such a way that it was possible to observe the sunrise through the “sacred gate” – a special arch or hole in the wall. All pagan religions celebrated the rebirth of the sun at the end of December, on the day of the winter solstice. “A child was born”, “light at the end of the tunnel”, “enlightenment” and “bright person” – similar expressions that convey the positive meaning of the word “light” exist in many languages. There is nothing surprising in such a reverence for the luminary: from the point of view of biology, we are daytime creatures and are directly dependent on the sun. Its light allows us to navigate in space and get aesthetic pleasure from the shapes and colors of the world around us.
Native to the equator
We feel the sun’s rays almost on a tactile level, like a caressing touch on the skin. Perhaps this is due to the fact that our distant ancestors were from Africa, where the ambient temperature is close to body temperature. “We don’t know exactly what color the skin of hominids, the first upright, who appeared about 5 million years ago in Africa, was,” comments the geneticist. Svetlana Borinskaya. “Most likely she was swarthy due to intense sunlight. A small part of the Africans went beyond the continent and gave rise to other races. Adapting to a lower level of solar radiation, the human body accumulated mutations: the skin and hair became more and more light. About 70 thousand years ago, our ancestors settled so far from the equator that they needed clothes – the sun’s heat was no longer enough to maintain a comfortable temperature for the body. We have long forgotten how to do without clothes, but we invariably experience pleasure, opening the body to the sun’s rays.
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- Vacation on the nose: which sunscreen to choose?
seasonal enlightenment
Our biological rhythms are cyclical and are associated with the alternation of day and night. “In the morning, between 6 and 8 o’clock, our sensitivity to light reaches its maximum, and the body programs itself for the next twenty-four hours,” says Olivier CoudronFrench chronobiologist. – In winter, a person receives only 2,5 thousand light units per day, and even less indoors (in spring – 7-10 thousand light units). In winter, we wake up in the dark and complete our daily activities many hours after sunset. Accordingly, light stimulation for the body is not enough. As a result, mood worsens, sleep and digestion are disturbed. Often these problems go away by themselves with the onset of a long daylight hours. Probably, this is also why we experience the arrival of spring as a moment of emotional awakening: we get up with the sun and fall asleep with the onset of darkness – this is the most comfortable mode for daytime creatures.
Is there an allergy … to the sun?
“Of course, the sun is not an allergen, and there is no allergy to ultraviolet light,” says Elena Tuzlukova, an allergist-immunologist, an employee of the Institute of Immunology of the Federal Medical and Biological Agency. – Skin rashes that appear under the influence of sunlight – photodermatitis – can have different causes. Firstly, these are photoallergic and phototoxic reactions, which are usually associated with the use of drugs or other chemicals. The components of medicines under the influence of sunlight can interact with skin proteins, causing an allergic reaction. Otherwise, the drug (or its components) itself undergoes a change under the influence of the sun, becomes toxic and causes a skin reaction. Another possible cause of photodermatitis is functional disorders of the gastrointestinal tract, most often the gallbladder and liver. Only a specialist can recognize the true cause of photodermatitis, who will help get rid of this trouble and enjoy the sun in the future.
The best antidepressant
Sunlight stimulates the production of endorphins, “pleasure hormones,” which is why sunlight is considered to be the best natural antidepressant. Its positive influence also extends to the sphere of interpersonal relationships: while the cold encourages us to “close”, the sun, on the contrary, “opens” us in relation to the outside world, to those around us. It is for this reason that in the summer it is easier for us to make new contacts, make new friends. “Visualization of the sun is very helpful in psychotherapy,” says psychologist Julia Zudina. – Its light dispels the shadow of uncertainty, anxiety, fear, it is a force that conquers chaos. The sun is one of the main and invariably positive archetypes, a warm, life-giving principle. The visualization of the circle, which is an ancient symbol of the sun, creates a sense of security, wholeness, a sense of harmony.
In order to get the maximum anti-stress effect from sunbathing while lying on the beach, psychotherapists recommend the following techniques: breathe slowly, completely filling the lungs with air, and freely slide an unfocused gaze over the water surface. The positive effect is enhanced by color therapy: the water absorbs the exciting red colors of the spectrum and reflects the blue ones, which soothe the nervous system and relax the body.
Light in your eyes
Sunlight is one of the reasons for the aging of the lens of the eye: the risk of developing cataracts (in which the lens loses its transparency) for residents of sunny countries is about three times higher than for the rest. Today, cataracts are successfully operated on, but in 40% of cases this disease can be prevented *: on sunny days, on the beach or in the mountains, it is necessary to wear (from a very young age) high-quality glasses that protect against ultraviolet rays A and B. Strengthening vision “from the inside” will help regular inclusion in the menu of spinach, parsley and cabbage, rich in vitamin C.
POLA-INSERM study, 2000.
sunshine vitamin
Under the influence of ultraviolet radiation, our skin produces vitamin D, which prevents calcium from being washed out of bones and teeth, protects the heart and blood vessels, and prevents the occurrence of certain cancers. Thanks to vitamin D, melanin is evenly distributed in the skin, and it gets an even tan. Professor Michael Holick from the Boston Graduate School of Medicine (USA), one of the most respected researchers on the properties of vitamin D and the author of more than 100 scientific articles, recommends that during the sunny season, expose your hands, face or legs to the sun 2-3 times a week for 5 -10 minutes without protecting them in any way, and … precisely at noon! He believes that in such a short time we only benefit from the sun: under the influence of high-intensity ultraviolet, vitamin D accumulates in the subcutaneous fat layer, and as a result, the body’s needs for it will be satisfied for the whole winter.
risk and pleasure
Ultraviolet is the invisible, short-wavelength part of the solar radiation spectrum. Depending on the wavelength, ultraviolet is divided into three types: A, B and C. The hardest radiation C (UVC) practically does not reach the Earth’s surface, being completely absorbed by the ozone layer. Ultraviolet B (UVB) not only stimulates cells to produce melanin, but also causes skin redness, erythema, which is the first sign of a burn. The mechanism of action of UVB on our body was studied in the middle of the last century. At the same time, the first sunscreens were invented. They were created on the basis of mineral filters – titanium and zinc oxides, which reflect part of the ultraviolet spectrum, mainly UVB. At the same time, they began to use the SPF index (Sun Protecting Factor), which shows how many times the impact of ultraviolet B radiation is weakened when using a protective agent. As for rays A (UVA), they are even more penetrating than rays B, neither clothes nor glass stop them, they bypass all barriers and act on the skin all year round. “Today, it has been clearly proven that it is UVA that penetrates the epidermis into the deeper layers of the skin and causes the destruction of collagen and elastin (structural skin proteins), the appearance of pigmentation and premature wrinkles,” says L’Oréal dermatologist Marina Kamanina. – In the 90s, scientists started looking for protection against UVA. All possible substances that absorb this type of radiation were either unstable in the light or did not combine well with UVB filters, so the first task was to synthesize a special molecule that would absorb both types of ultraviolet. Just a few years ago, the L’Oréal labs created the versatile Mexoryl XL photostable filter that absorbs both UVA and UVB rays.”
Modern adequate protection (the use of sunscreens with UVA and UVB filters and an index corresponding to the skin phototype) and the implementation of certain rules will allow you to get both benefit and pleasure from sunbathing, believes Marina Kamanina. “Firstly, limit the time spent in the sun in the first days of the holiday,” she advises, “the abuse of the sun leads to suppression of the immune system, and it will be more difficult for the body to acclimatize. Secondly, direct sunlight should be avoided from 11 am to 15 pm, when the radiation intensity reaches its maximum. Thirdly, pay attention to reflective surfaces (water, pool side): the more they reflect the sun’s rays, the more ultraviolet radiation the skin receives. In this case, it is better to reduce the time spent in the sun.
Good tan in facts and figures
- A tan appears on the skin after 48 hours – this is how long it takes for the synthesis of melanin.
- Melanin, the pigment that gives color to our skin, serves as a natural solar filter, absorbing 30-70% of UVB that penetrates the skin, and up to 90% in people with black skin.
- The phototype depends on the type of pigment that prevails in the skin: white-skinned people (especially with red hair) have more pheomelanin, while dark-skinned people have more eumelanin. Pheomelanin absorbs ultraviolet much worse, so the likelihood of getting a sunburn in such people is about 60 times higher than in blacks.
- Pheomelanin also contains sulfur atoms – under the influence of sunlight, sulfur derivatives that are toxic to skin cells can be formed. Therefore, white-skinned red-haired people are most prone to various health problems due to the abuse of the sun.
- The penetrating power of ultraviolet A is a hundred times higher than that of B rays, which do not penetrate deeper than the upper layers of the skin. Approximately 80% of UVA penetrates the skin to the level of the dermis, and the remaining 20% penetrates into the deeper layers of the tissue.
- Ultraviolet inhibits the activity of immune skin cells (Langerhans cells), which leads to the activation of viruses that are peacefully dormant in the body. Therefore, the abuse of the sun often causes an exacerbation of herpes or the growth of papillomas.
- A two-week course of vitamins provides skin protection corresponding to SPF2. Vitamin C boosts immunity by stimulating the growth of the number of lymphocytes and the production of antibodies in the blood. Vitamin E neutralizes partially reactive oxygen species, acting as an antioxidant. Carotenoids (derivatives of vitamin A) due to their special chemical structure can trap and neutralize free radicals.
Based on L’Oréal Laboratories research.