Patient information from BMJ

Staying safe in the sun

Last published:Oct 11, 2021

It is important to use sunscreen when you're out in strong sunshine for more than a short time. This helps protect your skin from sun damage and reduces your chance of getting skin cancer.

But you need to make sure you use a sunscreen that gives enough protection.

This leaflet is about protecting your skin from the sun.

But it's actually important to spend some time in the sun. This is because sunlight is the main way that we get vitamin D. Vitamin D is found in some foods. But it's hard to get enough vitamin D just from diet alone.

In countries that don't get much sun in the winter, doctors often recommend that people take vitamin D supplements in those months.

Vitamin D is important in keeping our immune system working well, and in keeping our bones and teeth strong. It also helps protect against many health problems, including:

• several types of cancer, including breast cancer, prostate cancer, and colon cancer

• heart disease

• diabetes

• depression, and

• weight gain.

So how much sun is a safe and helpful amount? The answer is that we don't really know. Some doctors advise that being outside with your arms uncovered for about 20 minutes a day is enough to get the vitamin D that you need.

What we do know is that the chance of skin cancer is greater if your skin burns.

So, while it's healthy to expose some skin to the sun for a short time, it's important to avoid sunburn.

If you are going to spend longer in the sun - for example if you are on holiday, going for a long walk on a hot day, or gardening in sunny weather, you should think about sunscreen.

Sunscreens protect you against a kind of sunlight called ultraviolet (UV) light. There are two main types of UV light that affect the skin: UV-A and UV-B. UV-A can cause skin cancer and wrinkling. UV-B can cause skin cancer and burning.

Some ingredients in sunscreens protect you against one type of UV light but not the other. To get protection against both types of UV light, use a sunscreen that’s labelled as a broad-spectrum sunscreen. 

Also, look for a sunscreen with high SPF rating. SPF stands for sun protection factor. It indicates how much protection the sunscreen provides against UV-B light. The highest SPF that can be legally marketed in most countries is 50. You shouldn’t go any lower than 15, as this won’t protect your skin against cancer.

Here are some other tips for protecting yourself and your family when you're out in the sun.

• If possible, stay out of the sun when it's at its hottest. This could be as long as between 10 a.m. and 4 p.m. if you are in a hot country.

• Wear a hat.

• When possible, wear clothing that covers your skin, such as long-sleeved tops, trousers, or a long skirt or dress.

• Wear sunglasses. These will help protect your eyes and the skin around them.

• Spread the sunscreen evenly on all the skin that will be in the sun.

• Use enough sunscreen. To get the right amount, use the 'two-finger rule'. Squeeze out sunscreen along the length of your first two fingers. Use this much sunscreen on each of these parts of your body: your head, neck, and face; each arm; upper back; lower back; chest; stomach; each upper leg (back and front); and each lower leg (back and front). This can take some time to do properly.

• Put on sunscreen 15 minutes before you go out in the sun.

• Reapply your sunscreen regularly. Try to reapply at least every two hours, and more often if you've been swimming or sweating a lot.

• Reapply sunscreen more often when you're out in the snow or in water. The sun's rays reflect off the surface of snow and water, which means you get more sun.

• Don't stay in the sun longer just because you're using sunscreen. You can still get burnt. If you use sunscreen to stay in the sun longer, you can actually increase your chances of getting skin cancer.

• Don't use sunbeds.

See your doctor if you notice any new blemishes or changes in a mole.

Take extra care with children's skin

Children and teenagers are more likely to spend a long time in the sun, so it's important to take special care of their skin. If the sun damages their skin, they're more likely to get skin cancer when they get older.

Babies under 6 months old should stay out of the sun because their skin is thin and sensitive, and sunscreens may give them a rash.