The controversy surrounding the positive and negative effects of UV rays on human health continues, however, more and more people are afraid of skin cancer and early aging caused by the sun. However, the star that gives light and life to all living things plays an indispensable role in maintaining health, not only thanks to vitamin D. UC San Diego researchers studied satellite measurements of sunlight and cloudiness during the winter to estimate serum vitamin D levels in 177 countries. Data collection revealed an association between low vitamin levels and the risk of colorectal and breast cancer. According to the researchers, “The amount of sun exposure you get during the day is key to maintaining a healthy circadian rhythm. These rhythms include physical, mental and behavioral changes that occur over a 24-hour cycle and respond to light and dark,” says the National Institute of General Medical Sciences (NIGMS). The sleep-wake cycle largely depends on the morning dose of sunlight. Natural daylight allows the internal biological clock to tune in to the active phase of the day. That is why it is so important to be in the sun in the morning, or at least let the sun’s rays into your room. The less natural light we get in the morning, the harder it is for the body to fall asleep at the right time. As you know, regular sun exposure naturally increases serotonin levels, which makes a person more alert and active. A positive correlation between serotonin levels and sunlight has been found in volunteers. In a sample of 101 healthy men, the researchers found that the presence of serotonin in the brain decreased to a minimum during the winter months, while its highest level was observed when the participants were under sunlight for a long time. Seasonal affective disorder, which is characterized by depression and mood swings, is also associated with a lack of sunlight. Dr. Timo Partonen from the University of Helsinki, along with a team of researchers, found that blood levels of cholecalciferol, also known as vitamin D3, are relatively low during winter. Sun exposure during the summer can supply the body with this vitamin to last through the winter, which promotes the production of vitamin D, which increases serotonin levels. The skin, when exposed to ultraviolet rays, releases a compound called nitric oxide, which lowers blood pressure. In a recent study from the University of Edinburgh, dermatologists examined the blood pressure of 34 volunteers exposed to UV lamps. During one session, they were exposed to light with UV rays, during another, the UV rays were blocked, leaving only light and heat on the skin. The result showed a significant reduction in blood pressure after UV treatments, which cannot be said for other sessions.
The photo shows people with tuberculosis in Northern Europe, a disease often caused by vitamin D deficiency. Patients are sunbathing.