How can you protect yourself from UV light?

Shade is the best protection from the sun. It can reduce UV radiation by 50-95%. But not all shade is the same. Dense foliage in trees or bushes offers good protection and can stop more sunlight than many parasols. If there is no shade, you can wear suitable clothing instead. Wide-brimmed hats help, and parasols or umbrellas can offer additional protection for babies.

Clothing that is dark, tightly woven and unbleached offers the best protection. Polyester, denim (jeans) fabric and wool can stop more UV light than thin cotton, linen, silk or rayon.

Clothing with special built-in UV protection is also available. The amount of protection it offers depends mostly on how the fabric was produced. Some of these fabrics lose a lot of their protective ability when they are washed or get wet.

The “UV Standard 801” offers the most reliable indication of how well a fabric can protect you from sunburn. It involves testing used clothing in a standardized procedure. The ability of clothing to prevent sunburn is expressed as an Ultraviolet Protection Factor (UPF). The UPF determined based on this procedure describes how much longer you can stay in the sun without getting a sunburn. Thick cotton clothing has a UPF of about 20.

Sunscreens such as lotions or sprays can prevent sunburn if you reapply them often enough. This is important because sunburn is painful, damages the skin, and is associated with a higher risk of skin cancer.

But it’s not quite clear whether sunscreen can also protect you from skin cancer. Studies suggest that squamous cell carcinoma (cancer) is less common in people who use sunscreen. But using sunscreen hasn’t yet been shown to prevent the more dangerous type of skin cancer known as melanoma or the more common basal cell carcinoma. Most of the studies in this area don’t include information about important factors such as the skin type of the participants. In some studies, the participants were only asked how often they used sunscreen in the past. But it's almost impossible to remember how often and how well you used sunscreen years or even decades ago.

Most of the studies also used older sunscreens that had no UVA filters and relatively low sun protection factors (SPFs). There is even less research on newer lotions that have a higher SPF and a UVA filter.

Even though so many questions remain unanswered, sunscreen is still a good way to protect yourself, along with other measures. There are some activities – such as hiking, swimming and surfing – where there is no shade or clothing alone can’t provide enough protection. You are even more exposed to the sun when you swim or do sports in the water because the UV rays are reflected by the water. The rays can penetrate the water up to a depth of 1 meter as well. Parents often find sunscreen to be the most practical way to protect their children from the sun. Children don't always want to stay in the shade, and often take off their clothes anyway.

But relying only on sunscreen has one definite drawback: It is difficult to check how much protection you have. You can't easily tell whether you have applied enough sunscreen everywhere or whether it has worn off. And people who use sunscreen may be less likely to protect themselves from the sun in other, more effective, ways.

A sunscreen’s sun protection factor (SPF) indicates how long it can protect you from UVB radiation and sunburn. Whether or not a sun lotion also filters out UVA radiation is shown separately, for instance in the form of a small circle with the letters “UVA” inside it. Sunscreens that offer protection from both UVA and UVB rays are the best at preventing sunburn.

Your skin can protect itself from UVB radiation for a certain amount of time. The SPF lets you know how much longer (at the most) you can safely stay in the sun by putting on the lotion. To find this out, you multiply the SPF by the length of time you have natural protection. For example:

If you have skin type I, your skin naturally provides up to 10 minutes of protection. Using a lotion with SPF 15 means that the maximum time you will be protected is 10 x 15 (150) minutes, which is 2.5 hours.

It is somewhat simpler to use the SPF categories shown on sunscreen products. They divide the level of UVB protection into four basic categories:

Most sunscreen products contain both chemical and physical UV filters. The types of UV filters that are approved for use in sunscreens vary from country to country.

Chemical filters are substances that are absorbed by your skin to block UV rays there. Different types of chemical UV filters are usually combined to cover more of the UV spectrum. Physical filters contain particles (mineral pigments) that shield your skin from UV light. The most commonly used particles are made of titanium dioxide and zinc oxide. Sunscreens that use mineral pigments are believed to be better tolerated by your skin than ones using chemical filters. However, some sunscreens that contain mineral pigment filters leave behind a whitish coating that might be considered a nuisance.

Some face creams and foundations also have UV filters. But their SPFs are often not clearly labeled, so it’s difficult to rely on them for protection.

Putting on sun lotion sounds like a simple enough thing to do. But many people don’t put it on properly, or might not be sure when to use it, how much to use, or how often they should reapply it. It is also important to choose a sunscreen with a sun protection factor that is right for your skin type and offers enough protection.

Sunscreen is only effective if it is applied generously. If used correctly, an adult will be able to use a 200 ml bottle of sun lotion to cover their entire body six times before it runs out.

When you put on sun lotion it’s important to remember every part of your skin that is exposed to the sun. It is easy to forget areas like your ears or feet, and some people don’t like asking for help with areas like their back. Lotions can wear off if you sweat, get wet or dry yourself off with a towel, leaving you with less protection. Even products labeled as “waterproof” aren't 100 percent waterproof and may be rubbed off. So it’s a good idea to keep reapplying sunscreen – about every two hours. You could use a reminder, for instance using your cell phone. But a sunscreen’s maximum protection time can't be extended by putting on several layers of it in one go.

It is also important to put on sunscreen before you go out and not wait until you’ve already been in the sun for a while. Most sunscreens start working immediately after you put them on. Some products take about 20 to 30 minutes before they offer protection.

Quite a lot of people think about putting on sunscreen when they are on vacation or going out to sunbathe, but not many people give it much thought in everyday life. Of course, it’s not always possible to know when you’re going to be in the sun, and it can be difficult to guess how strong the sun will be. But you can get a sunburn anywhere – for instance, sitting outside at a café or wandering around a market.

There’s no doubt that using sunscreen regularly can be bothersome, and especially children find it annoying. It is often easier if putting on sunscreen in the summer is part of a fixed routine, and if the lotion smells good and reminds them of the beach and vacation time.

The chemicals and additives in sunscreens cause side effects in about 20 out of 100 people who use them. Although these side effects don’t lower the amount of protection provided, problems like red or inflamed skin and allergic reactions can be unpleasant. In very rare cases people have bad allergic reactions that need immediate medical attention.

If your skin is especially sensitive, it may react to additives like emulsifiers, fragrances, dyes or preservatives. If the sunscreen doesn’t have any additives in it, that will usually be clearly stated on the package. Sunscreen that only contains physical UV filters is often better tolerated.

Especially sunscreens with a high SPF may stain clothing or furniture.

Some people worry that their body won’t produce enough vitamin D if they avoid the sun. But there is usually no cause for concern: Your face and hands are typically exposed to the sun for a short time in everyday life – that’s normally enough. Plus, our bodies can store vitamin D. But people who never go out in the sun or are always completely covered up can’t produce any vitamin D and have to rely on getting it in the foods they eat. Our bodies need vitamin D to make bone tissue.

The desire to get a tan sometimes simply outweighs the wish to protect yourself from the sun. Many people prefer the way they look when they are tanned. Most think that a light tan makes you look healthy, rested and athletic. Sometimes a tan might just be seen as proof that you’ve had a nice vacation. Biologically speaking, though, a tan is nothing more than the skin’s reaction to protect itself from being damaged by too much UV light.

A lot of people still want to get a tan on vacation even though they know that too much sun will increase their risk of getting skin cancer. How much people worry about skin cancer can vary quite a bit. Some people don’t think skin cancer is that dangerous, or they downplay the risk. Others think it's more important to avoid short-term problems like sunstroke or sunburn. It is commonly assumed that getting a tan while enjoying outdoor activities is healthier than sunbathing or using a tanning bed.

Although it’s sensible to be careful, most people need sun and fresh air to feel good. So it’s about finding the right balance in order to allow you to relax and enjoy the summer outdoors.