Best time to sunbathe - How long is enough?

The article is expertly consulted by Assoc. Dr. Dr. Huynh Thoai Loan - Head of Pediatrics - Neonatology Department, Vinmec Central Park International General Hospital. He is one of the leading experts in Pediatrics - Neonatology in Ho Chi Minh City with nearly 30 years of experience in examining and treating pediatric endocrinology, pediatric kidney and other pediatric - neonatal problems. .

Up to 80% of the vitamin D needed by the body is synthesized by direct exposure to sunlight every day. However, sunbathing is not always good. If sunbathing at the wrong time, in the wrong way and sunbathing for too long can cause skin damage, especially with the immature skin of babies and children.

To know the best time to sunbathe, it is first necessary to understand what role the sun's rays play in affecting and stimulating the synthesis of vitamin D, thereby knowing which rays are harmful and which rays are beneficial. for the skin.
Sunlight consists of visible rays (rainbow) and invisible rays which are ultraviolet or UV rays. UV rays are divided into 3 types: UVC rays, UVA rays and UVB rays.
UVC rays: have a short wavelength of about 200 - 190 nm. This type of radiation is the most harmful to human health. But UVC rays are absorbed by the ozone layer before reaching the ground, so they have almost no effect on the skin and do not synthesize vitamin D. UVA rays: accounted for 95% of total UV radiation in sunlight. to the ground, has the longest wavelength about 320-400 nm. UVA rays have the ability to penetrate the ozone layer, clouds, water, glass, thin clothing. Even some sunscreens do not block the effects of UVA rays. Thus, UVA rays appear throughout during sunlight, even when it is cloudy or rainy, UVA rays still appear. UVA rays are the main cause of skin darkening, skin aging, tanning, freckles and increasing the risk of skin cancer. Like UVC rays, UVA rays are completely incapable of synthesizing vitamin D. UVB rays: The only rays in sunlight that can stimulate vitamin D precursors, support calcium absorption in the body. People. UVB rays have a shorter wavelength than UVA rays, about 290 - 320nm. Up to 95% of UVB rays are absorbed by the ozone layer. Only very few UVB rays penetrate the ozone layer to the Earth's surface.

UVB rays are the only rays capable of synthesizing healthy vitamin D, so it is necessary to choose the time with the most UVB rays to sunbathe.
The time when UVB rays can penetrate the ozone layer the most is between 9am and 4pm. However, during this time in the sun, there are a lot of harmful UVA rays that are harmful to the skin, especially for the delicate skin of babies and children.
Therefore, the best time to sunbathe is before 9am and after 4pm, when the sun is not too strong.

Although UVB rays have the ability to stimulate vitamin D synthesis, prolonged exposure to UVB rays or intense exposure can also damage the skin. Therefore, do not stay in the sun for too long. You should only sunbathe for about 20-30 minutes at a time, depending on the degree of sun exposure to the skin. The first time sunbathing for children should only last about 10 minutes and gradually increase the duration as you get used to it.
Unlike UVA rays, UVB rays are not able to penetrate clothing and glasses, so when sunbathing, it is necessary to expose the skin and sunbathe directly, do not let children sunbathe through the glass window. Children can be undressed slowly, sunbathe their feet, calves, thighs, then hands, forearms and finally back.
Note, sunbathing only provides about 80% of the amount of vitamin D needed by the body. Therefore, it is still necessary to supplement vitamin D for children through breast milk and daily food. In addition, parents can also give their children vitamin D3 supplements according to the correct dosage appropriate for each age group and the manufacturer's instructions.
As a key area of ​​Vinmec Health system, Pediatrics Department always brings satisfaction to customers and is highly appreciated by industry experts with:
Gathering a team of top doctors and nurses in Pediatrics : consists of leading experts with high professional qualifications (professors, associate professors, doctorates, masters), experienced, worked at major hospitals such as Bach Mai, 108.. Doctors All doctors are well-trained, professional, conscientious, knowledgeable about young psychology. In addition to domestic pediatric specialists, the Department of Pediatrics also has the participation of foreign experts (Japan, Singapore, Australia, USA) who are always pioneers in applying the latest and most effective treatment regimens. . Comprehensive services: In the field of Pediatrics, Vinmec provides a series of continuous medical examination and treatment services from Newborn to Pediatric and Vaccine,... according to international standards to help parents take care of their baby's health from birth to childhood. from birth to adulthood Specialized techniques: Vinmec has successfully deployed many specialized techniques to make the treatment of difficult diseases in Pediatrics more effective: neurosurgery - skull surgery, stem cell transplantation. blood in cancer treatment. Professional care: In addition to understanding children's psychology, Vinmec also pays special attention to the children's play space, helping them to have fun and get used to the hospital's environment, cooperate in treatment, improve the efficiency of medical treatment.