Why You Should Put on Sunscreen Before You Go On Vacation

Right now, at least in the northern hemisphere, we’re enjoying summer. But summer will yield to fall and ultimately, to winter. And some of us will get on airplanes, destined for warmer destinations. Sunlight, 80-degree temperatures, and a cool drink in your hand as you sit on the beach or next to the pool? That sounds great in February, doesn’t it?

Just don’t forget the sunscreen. It’s important! In fact, you probably should put it on before you even get on the plane.

You won’t be alone: most likely, the pilots and attendants are wearing sunscreen, too. Even if they’re not going someplace warm.

The sun emits ultraviolet light that isn’t visible to humans but is still definitely there, and our skin absorbs those UV rays when exposed to them. Prolonged exposure to UV rays causes sunburns and can ultimately cause skin cancer. As Live Science explains, sunscreen is our shield against this harmful sunlight. First, sunscreens typically contain “minerals such as zinc oxide or titanium dioxide, act as a physical sunblock. They reflect UV rays, similar to how white paint reflects light.” And second, “sunscreens often contain organic chemicals, with names such as avobenzone or oxybenzone. Instead of physically deflecting UV light, these molecules absorb UV radiation through their chemical bonds.” No solution blocks all of the UV light, but this is your best bet if going to the beach.

But the beach isn’t the only place you’ll be exposed to UV light — that happens virtually everywhere. And as it turns out, there are two types of UV radiation. The type that causes sunburns is called UVB, and, good news: most windows can screen that out for you, so you don’t have to worry about that when indoors. Windows aren’t nearly as good at screening out the other type, called UVA radiation, though. In most situations, the risk is minimal, as you’re not going to have prolonged exposure to direct sunlight in your normal, day-to-day lives. But otherwise, UVA radiation is dangerous. Per Yale Scientific, UVA rays “penetrate more deeply into the skin and were once thought to only cause skin aging and wrinkling. However, recent research has confirmed that UVA rays also play a significant role in the development of skin cancer.”

And if you’re on an airplane — particularly in a window seat or in the cockpit — you’re exposed to a lot of UVA radiation. As travel site The Points Guy relays,  a typical “plane’s windows [stops] about 99% of UVB rays, but only about half of UVA rays.” And further, per The Points Guy, “since you’re closer to the ozone layer — almost six miles closer to be more exact — the sun’s rays are simply more powerful.” That can be a bad combination, as Conde Nast Traveler explains: “A recent study in JAMA Dermatology found just one hour at 30,000 feet could expose pilots to the same amount of UV radiation as a 20-minute tanning bed session would. But as a passenger, you’re up against a smaller window and far less cumulative exposure. Still, over time, hours in the sun (yes, even by a window) add up, increasing your risk of skin cancer.”

Sitting on the aisle or pulling the window shade down both help, but not as much as you may think. The Cut spoke with a pair of dermatologists who explained that the “super-strong light” from being so high up is a unique problem; the plastic shades will block some UVA radiation, but definitely not all of it, and of course, there’s all the light from the passengers who don’t pull their shades down. Further, the clouds outside the plane are “highly reflective of UV light. All those cute cumulus and cirrus clouds can fill the cabin with ambient ultraviolet light, regardless of where you’re sitting.”

So if you’re flying, do what many pilots and flight attendants do: put on sunscreen before you board your flight. If you’re going somewhere warm, you’ll have some anyway; if not, at least you can pretend you’re off to somewhere tropical. And you’ll protect yourself at the same time.

Bonus fact: If you’re playing competitive water polo outdoors, you’ll definitely want to wear sunscreen — again, the UV radiation is bad for you. But don’t overdo it, or you may lose your match. The Fédération Internationale de Natation (FINA) is the international regulatory agency for the sport, and too much sunscreen can make it harder for opponents to grip one another. So, FINA  adopted a rule (5.5 in this pdf) stating that “players shall not have grease, oil or any substance on the body which might provide an advantage.” An over-lotioned player may be removed from the match.

From the Archives: The Shape of Safety: Why airplanes have oval windows.