Sunlight is a source of vitamin D, essential for healthy bones and teeth, but you only need to spend a little time in the sun to meet your body’s quota. And as the saying goes, too much of a good thing is bad for you; the same applies to sun exposure.

Too many stints soaking up the rays can lead to wrinkles, skin damage and, at worst, cancer.

How do SPFs work?

We’ve all seen the sun protection factor (SPF) numbers on the bottles and tubes of sunscreen, but what do they mean? Whether it’s a 15, 30 or 45, it tells you how long a sunscreen will protect you from ultraviolet B (UVB) rays, which cause painful sunburn and damage your skin.

For example, SPF 30 will allow you to stay in the sun 30 times longer than without sunscreen. So if your skin starts reddening after 10 minutes in the sun, a factor of 30 will protect you for around five hours.

However, this guideline is not absolute, and not all numbers are created equal. It’s not as simple as a 30 protecting you for double the time of a 15. In reality, an SPF 15 blocks about 94% of the harmful rays, an SPF 30 about 97%, and an SPF 45 about 98%. Recently, SPFs of 70 and more have appeared on shelves, but any sunscreen with an SPF higher than 50 isn’t necessarily more effective.

Sunscreen vs. sunblock

While SPF protects against UVB rays, UVA rays are far more dangerous as they penetrate deeper into the layers of your skin. They are the primary cause of long-term damage, including wrinkles and skin cancer, and the best sunscreen won’t protect you from them. For UVA protection, you’ll need a sunblock.

You know the white facial stripes sported by cricketers and lifeguards? Well, they’re not just to look cool or represent tribal markings. They contain zinc oxide and titanium dioxide, which work as an effective sunblock. However, unlike sunscreen, there’s no general measure as to how long sunblock will keep you protected.

Daily sun care

Only mad dogs and Englishmen go out in the midday sun. So, the first rule is to avoid being in the sun between 10 a.m. and 4 p.m. When you go out, slather all exposed areas with sunscreen about 20 minutes beforehand and reapply at least every two to three hours.

Sunscreen isn’t foolproof – sweat and water will wash it off. If you’re playing sport or frolicking in the water, make sure you apply more frequently. Although sunscreen is pricy, don’t be stingy about the amount you use. A good palm-sized dollop should be used for each application, and don’t forget to coat the tips of your ears, the back of your neck and hands, and under the edges of your clothes or swimming costume. Because sunscreens are loaded with chemicals, check the labels carefully for anything you might be allergic to.

Lotions aren’t the only essentials in protecting you from the sun – clothing and hats make a big difference, too. Dark colours block out more UV radiation, and closely woven fabrics offer more protection than flimsier ones. To check whether your clothes are sunwise, hold the garment up to the sun; if light gets through, then so will the harmful rays.

Eye wise

Don’t forget your eyes. The sun can burn your corneas, and long-term exposure can cause cataracts when you’re older. So sunglasses are not just for looking trendy. Steer clear of the fashion accessories that are more pretty than practical – check that your sunnies have a label saying they offer 100% UV protection.

DISCLAIMER: The information on this website is for educational purposes only, and is not intended as medical advice, diagnosis or treatment. If you are experiencing symptoms or need health advice, please consult a healthcare professional.