Sun Safe Through Any Activity: Sweating, Stinging, & the Solution

As the mercury starts to rise, so does the anticipation of spending time outside in the sun. You may be making plans for a hiking trip, brushing up on your tennis game, or simply looking forward to walking to work each day.

No matter your level of physical activity, spending time in the sun naturally brings up questions about the strength of your sunscreen—will it stand up to sweating? What about a day swimming at the beach? 

We love when our community gets proactive about their sun safety, so we’re answering a few common questions about sunscreen during sportier summer pursuits:

Waterproof vs. Water-Resistant—How Long Does My Sunscreen Really Last in the Water? 

No sunscreen is “waterproof.” In fact, the term is no longer allowed by the FDA. Instead, sunscreen companies must substantiate claims that they are either “40-minute water resistant” or “80-minute water resistant.”

Any sunscreen that sports a water-resistance claim should have undergone testing from an independent laboratory, and proved that it upholds the same SPF coverage after the allotted amount of time.

The 40-minute water-resistant test consists of participants who begin by applying sunscreen 15 minutes prior to sun exposure. Then, they engage in 20 minutes of “moderate water activity,” take a 20-minute rest period without toweling dry, and then another 20 minutes of moderate water activity. This process is repeated for the 80-minute designation.

While the water-resistance testing process above seems quite straightforward, there are three important factors to note:

  1. “Applying sunscreen 15 minutes prior to sun exposure”—This ensures that the ingredients are properly bound to the skin, giving you the full SPF benefit.
  2. “Moderate water activity”—For many swimmers, triathletes, and surfers, this designation is not extensive enough for your scope of movement—you should consider applying more frequently.
  3. “Toweling dry”—Sunscreen must always be reapplied after toweling off, no matter how long its water-resistance claim.

For those who love to spend a day at the beach or go for a long swim, you are sufficiently protected, without worry, for 80 minutes. Sunscreens like Sunology ensure that you can enjoy the sun with as little hassle of reapplication as possible.

Does wearing sunscreen make me sweat more?

For those who run, bike, or just take the dog for a walk—you may feel like you’re sweating more on the days you wear SPF.

You’re actually sweating the same amount each time it’s warm, whether you’re wearing sunscreen or not. But the rate at which your sweat evaporates varies depending on the “texture” of your skin.

Without SPF, your skin is more “rough,” which means that your skin forms smaller droplets of sweat, which evaporate faster. Once you apply sunscreen, the surface of your skin smoothens, causing droplets to merge together and form larger beads of sweat. Larger droplets mean a longer evaporation time.

For those familiar with exercise in humid climates, the same logic applies—more humidity means slower sweat evaporation. Sweating may be unavoidable, but at least you can be assured that your skin is staying protected!

Will it sting?

If you’re using a mainstream chemical sunscreen, sweating often means stinging. For the all-too-common stinging eyes, and maybe even skin, there’s an easy solution—avobenzone-free sunscreen.

Avobenzone is a chemical used in many chemical sunscreens for its ability to absorb a wide array of ultraviolet radiation—specifically UVA rays, known for causing sunburn. But studies show that avobenzone degrades when exposed to sunlight.

The breakdown of avobenzone causes the release of free radicals, which to you, may feel like a prolonged stinging sensation. That’s because free radicals are associated with many common allergies, as well as accelerated skin aging.

Eliminating avobenzone will rid your routine of a harsh unnecessary ingredient, and eventually you’ll forget all about the once-sting of sun protection.

 The Simple-Solution

“Physical” sunscreens sit on top of the skin and use active mineral ingredients like zinc oxide and titanium dioxide to reflect UV rays away from your skin.

Physical sunscreens ensure that your skin is staying protected through any activity. While some occasions are bound to get sweatier than others, physical mineral sunscreens allow those with sensitive skin and eyes to use a higher SPF without the stinging sensation.

At Sunology, we choose a physical formulation because it maximizes comfort, protection, and ingredient safety. Our goal is to bring clarity to your protection, and peace of mind to all your outdoor adventures. 

Have a different sunscreen question? Leave it in the comments section! We’re always happy to chat.

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