New research suggests UV rays may not be the only damaging element to protect yourself from this hot summer season.

By By Genevieve Monsma
June 13, 2018
Photo: Jacob Lund/Shutterstock

Skin's enemy number one is the sun. You know that. But your hair dryer? Your workout? Science now shows that heat can also wreak some serious havoc.

"I knew something was up when my patients with melasma, who swore they were slathering on sunscreen and fading creams religiously and staying out of direct sunlight, found the dark patches and blotchiness on their faces were getting no better," says Shasa Hu, M.D., a dermatologist in Miami and a member of the Dr. Brandt Skin Advisory Board. "The more I looked into it, the more it became evident that reg­ular exposure to high tempera­tures appeared to be inducing oxidative damage and boosting melanin production in a way that was very similar to how UV rays cause hyperpigmentation."

For years, dermatologists have talked about the damage linked to UVA and UVB rays. "It's as if someone roped off just those two wavelengths from the rest of the cascade of light. But we are also regularly exposed to visible light and infrared radiation [which heats the skin] and are just now starting to understand that the whole spectrum affects the skin," says Neal Schultz, M.D., a derma­tologist in New York City and a member of the Shape Brain Trust. (Related: 3 Ways Your Phone Is Ruining Your Skin and What to Do About It)

So what is happening physi­ologically? "One theory is that heat causes blood vessels to dilate, which ups inflammation and trig­gers melanocytes to produce more pigment," says Marie Jhin, M.D., a dermatologist in San Carlos, California. This heat­-pigment link may be one reason why some patients suffer hyperpigmenta­tion after laser treatments; people whose skin tone has more pigment (typically those of Asian, His­panic, Indian, and Middle Eastern descent) and everyone with melasma seem most vulnerable. (Related: How to Even Out Your Skin Tone with Laser Treatments and Peels)

Extra pigment, however, is not the only marring experts believe we sustain from heat exposure. After studying the topic for almost a decade, researchers at Seoul National University College of Medicine say it can also inhibit the skin's ability to protect and repair itself. Heat can lower antioxidant levels and raise proteins that break down the skin's spongy collagen supply, causing fine lines and sagging. A study published last April in the Journal of Drugs in Dermatology that tested the efficacy of a sunscreen (SkinMedica Total Defense + Repair SPF 34) reached similar conclusions about heat and skin.

Heat may also lead to a "compromised barrier function, which can cause chronic irritation of the skin," says Carl Thornfeldt, M.D., a dermatologist in Fruitland, Idaho, and the founder of Epionce skin care. Several doctors cited the condition erythema ab igne, sometimes referred to as "hot water bottle rash" and "toasted skin," as an extreme result of long-term or frequent exposure to infrared radiation. Usually characterized by red, mottled, lacy-looking skin, erythema ab igne typically develops after weeks of direct heat exposure. "We are talking about direct contact of about 113 degrees Fahrenheit, so not enough to burn your skin but enough to really heat it up," says Dr. Hu, who points to a heating pad or a laptop placed on your thighs for hours as common causes. Erythema ab igne is extreme irritation caused by heat, but Dr. Hu believes the same inflammatory response can cause less severe damage too, such as broken blood vessels, sensitivity, and a worsening of inflammatory conditions like rosacea, acne, or psoriasis. (Here are the best ways to calm red skin after a workout.)

Now for some good news. "Some of what you're already doing to protect your skin from UV rays may help minimize the impact of heat as well," Dr. Jhin says. "Physical sunblocks that contain zinc or titanium dioxide can help quell heat's temperature-raising impact because they act like a wall, bouncing light and heat off the skin." On the other hand, chemical sunscreens (such as those containing oxybenzone or avobenzone) absorb rays, which heats up the skin, Dr. Jhin says. In addition to wearing a broad-spectrum physical sunscreen, apply a mineral foundation to boost the heat-blocking effect of its SPF, Dr. Jhin adds.

Your behavior plays a role too. "If you care about the condition of your skin, you will have to make compromises-maybe you work out but skip the steam room. Or reduce your beach time from six hours to two," Dr. Hu says. The effect of heat is cumulative, so cutting down on exposure will decrease damage too.

You can also temper the effects of heat by taking a cool shower or spritzing yourself with cool water. "This enables a quicker recovery than if you just let your skin regulate itself," Dr. Hu says. Working from the inside out may help as well, says Dr. Thornfeldt, who suggests upping your intake of anti-inflammatory and cooling food and drinks, like iced spearmint tea, smoothies, even ice cubes. (Try these 15 anti-inflammatory foods.) The reverse is also true-if you're in a hot environment, don't compound the effect with caffeine, alcohol, and spicy foods, which boost blood flow to the skin and may magnify inflammation.

One final tactic: Help your skin help itself. "If you build up your skin's barrier function with skin care that contains lipids, ceramides, or noncomedogenic oils, you will minimize heat's ability to disrupt it and cause the inflammation that leads to hyperpigmentation, fine lines, and chronic irritation," Dr. Thornfeldt says. Applying topical antioxidants may also replenish those diminished by heat exposure. Layer an antioxidant serum under your favorite sunscreen each morning, or mix a vitamin C powder into any skin-care product to face the day more protected. (Related: Should You Swap Your Serum for Powdered Vitamin C for Glowing Skin?)

How to Protect Your Skin from Heat

Call on these beauty products to shield your skin from harm.

  • Vitamin C mix-in: Vitabrid C12 Face Brightening Powder ($60;
  • Mineral foundation: Jane Iredale Liquid Minerals Foundation ($52;
  • Cooling treatment: Clarins SOS Hydra Refreshing Hydration Mask ($34;
  • Antioxidant serum: Peter Thomas Roth Potent-C Power Serum ($95;
  • Zinc sunscreen: Drunk Elephant Umbra Sheer Physical Daily Defense SPF 30 ($34;