Is there a healthy way to be exposed to the sun?

Light has different types of radiation, some of which are visible to the human eye and others which are not. One of the types of radiation emitted is visible light which is, of course, visible to the human eye. On the radiation scale, visible light is between ultraviolet light and infrared light.

Ultraviolet light has more energy than visible light, but is not perceived by the senses. On the other hand, energy emitted by infrared light is perceived as heat. This energy is felt, for example, when sun shines through glass and the skin heats up, even if this protects from ultraviolet rays. Thus, complete light radiation always contains these types of radiation, but in different proportions. What do these proportions depend on? Dr Puig explains.

Ultraviolet radiation itself can be divided into UVA, UVB and UVC rays. “This ultraviolet light spectrum changes throughout the year and throughout the time of day we are exposed to it,” clarifies Dr Puig.

UVA rays can cause damage, such as ageing or skin cancer, while UVB rays are the main cause of sunburn. Approximately 10 times more UVA rays reach the Earth's surface than UVB rays.

Dr Puig explains the difference in ultraviolet radiation depending on the time of year “In the summer in Spain there is a lot of ultraviolet B (UVB) radiation. Although it is always in a smaller proportion than that of UVA. However, during these months there are UVB rays during more hours of the day.”

Despite knowing the types of radiation and their associated risks, this variability throughout the year or day can make it difficult to identify when sun exposure is best. Dr Puig has some very simple advice for knowing when exposure to the sun's rays is less dangerous. “When our shadow is long, that is when ultraviolet radiation is least damaging to our skin.” This happens during winter, when the sun shines more obliquely; or early in the morning or late in the afternoon during the summer. This is when ultraviolet radiation is less harmful to our skin.Therefore, exposure to the sun or outdoor activities is better when we cast a long shadow. "This is an easy way to simplify something which is more complex," explains Dr Puig.

However, intermittent exposure to strong sunlight, for example during the summer, is also associated with the development of skin cancer. Some melanomas are also associated with continued sun exposure throughout the year, for example, with outdoor workers. Therefore, you should always avoid the hours of greatest radiation and use sun protection, whether in the form of a cream, clothing, parasol or other methods.