Sun Protection and Sunscreen Facts

Sun protection is essential to prevent premature aging and skin cancer, which affects one in five Americans. The sun emits ultraviolet (UV) rays, which are a source of vitamin D. Too much UV exposure, however, can lead to skin damage.

How long does sunscreen last? It's important to reapply sunscreen every two hours or more frequently if you are sweating or swimming. Sunscreen typically expires after three years, so make sure to replace yours as needed. Read on to learn more about sun protection, including when and how to apply sunscreen. 

How Long Does Sunscreen Last?

The protection from sunscreen wears off over time. Make sure that you reapply sunscreen every two hours if you are outdoors. You'll need to reapply more frequently than that if you are sweating or swimming.

Sunscreen generally expires after three years. Replace your sunscreen sooner than every three years if it has an expiration date or has been exposed to high temperatures.

Can You Get Sunburned Through a Window?

You might assume that when you are inside, you do not need to wear sunscreen. You certainly feel warmer when you are sitting next to a window, so can UV rays reach you from outside?

The answer has to do with the two different types of UV rays: UVA and UVB. UVB rays are a shorter wavelength and are more closely associated with sunburns and skin cancer risk. These UV rays are mostly blocked by the tint of windows.

UVA rays may also play a role in skin cancer risk, but they are not as commonly associated with burns. These rays are more likely to add to discoloration and wrinkling of your skin. Research has shown that UVA rays can penetrate glass and reach your exposed skin.

Can You Tan With Sunscreen?

It's possible that you can tan with sunscreen since no product blocks 100% of the sun's UV rays. Sunscreen with an SPF of 30 absorbs about 97% of the sun's UV rays.

How Often Should You Reapply Sunscreen?

Use a shot glass–sized amount of sunscreen for exposed areas of skin and a teaspoon for your face and neck. Reapply every two hours or more often if you are swimming or sweating.

There's a chance cloudy summer days could lead to worse burns. These gray days tend to feel cooler, so you might be inclined to stay outside longer or forget to reapply sunscreen. UV rays are still potentially damaging and can age your skin, even if you do not burn on a cloudy day. Make sure you reapply sunscreen on cloudy days, on ski trips, on fall hikes—basically all year round.

How Long Should I Tan Outside Without Sunscreen?

You cannot tan safely. The American Academy of Dermatology Association (AAD) advises against any form of tanning, which damages the skin and increases the risk of skin cancer. You can instead use a self-tanner to bronze your skin, but make sure you also use sunscreen daily.

Remember, the idea that a base tan can avoid future sunburns is a big misconception. The base tan is sun damage. Just because you have some color does not mean you cannot also burn.

Is SPF 30 Enough?

Experts generally recommend using sunscreen with an SPF of 30 and above with what's called "broad-spectrum" protection. Broad-spectrum means the sunscreen shields you from both UVA and UVB rays. The higher the number, the smaller the number of UV rays that reach your skin. The number, however, may not be as crucial as you think. It's more important to focus on using enough sunscreen and reapplying it.

Using a higher SPF might give you a false sense of security that you are set for the day. The AAD reports that most people only use 20% to 50% of the recommended amount of sunscreen.

When Is the Sun the Strongest?

There's the potential for a burn where there's sunlight. The sun's rays are typically strongest between 10 a.m. and 4 p.m. These dangerous hours are determined by how high the sun is in the sky and can vary based on where you are. Remember, you could get burned whenever the sun is out.

Can You Get Sunburned in the Shade?

The shade does not completely protect you from the sun's UV rays, so it's possible to get sunburned. UV rays can reflect off of concrete, water, sand, and snow and reach you under the shade. Seeking shade is part of sun protection. Make sure that you also wear protective clothing and sunglasses and use sunscreen.

Do You Need Sunscreen After 5 P.M.?

It's safest to use sunscreen on exposed skin whenever you go outdoors, even after 5 p.m., especially if the sun is visible. It might not be necessary to wear sunscreen at night when the sun is not visible.

Remember, the risk of getting a sunburn is highest when the sun is strongest, between 10 a.m. and 4 p.m. This range can depend on your location. The higher the altitude, for example, the more likely you are to get a sunburn.

What Are 5 Ways To Protect Yourself From the Sun?

Here are some ways to protect yourself from the sun:

• Seek shade: Check your shadow, and get to shade if it's shorter than you.
• Use sunscreen: Apply sunscreen to exposed areas 30 minutes before heading outdoors. Be liberal with your sun-protective lip balm since you can also sunburn your lips.
• Wear sunglasses: Your eyes can burn and be damaged by UVA and UVB rays. The result is technically called photokeratitis, a painful eye condition that occurs when your eye is exposed to UV rays from the sun or man-made sources like tanning beds. Wear sunglasses that have UVA and UVB protection.
• Wear a hat: A wide-brimmed hat protects your face, including your eyes, from the sun.
• Wear sun-protective clothing: Opt for loose-fitting, tightly-woven long-sleeved shirts and long pants if possible. Some clothing even is made to absorb UV rays and protect your skin.

A Quick Review

Everyone needs sunscreen to minimize short- and long-term skin damage from the sun's rays. Using sunscreen, as well as seeking shade and wearing protective clothing and sunglasses, is an important habit to reduce your skin cancer risk. Always follow the best practices from experts to keep your skin healthy.