On a late July morning, the sun is already broiling the National Mall in Washington, D.C. The air is so humid, even a loose shirt quickly turns into a sticky mess.
Later, the heat index will top out around 103 degrees, turning the walk between air-conditioned museums into a scorching trek. I'm on my bike, in the hottest part of the summer tourist season, on a mission: to find visitors who are trying to beat the heat with an odd-looking gadget that's gained in popularity in recent years. It doesn't take long.
"These are amazing," says Christa Seger, who sits with three of her kids in the shade near the Washington Monument.
She holds up a cooling neck fan. It looks like a space-age horseshoe, but resting on your neck, it uses dozens of vents to blow air toward your ears and head. Some models — like Seger's — also have metal panels, to help dissipate heat.
"I can't believe how cold they get," says Seger, who's visiting from Denver.
Seger bought two fans for about $25 each a few days ago, back in Colorado.
"They last somewhere between 4 to 6 hours on a full charge," she says. Thinking the fans might help her daughter as they march from Smithsonian museums to historic buildings — and the occasional ice cream truck — she brought a battery pack to keep the fans juiced up.
"She loved it yesterday. It really helped her," Seger says.
Some of these fans can cost hundreds of dollars. But I'm trying out a very basic model today. As it powers on, air starts whooshing past my ears and neck. It feels like a nice breeze. But is it really doing anything to cool me?
How the neck fans work
Consider the main strategy our bodies use to cool down: sweating.
"The heat of vaporization gets pulled from that sweat into the atmosphere," says Dr. Adam Watkins of the University of Arkansas for Medical Sciences in Little Rock. "So you actually are losing heat that way."
But that's not always enough. Watkins says the emergency room where he works is seeing 25% more heat exposure cases this summer than last year — a trend he says has been rising over the past decade.
Intense heat waves are one reason why people might look to a personal cooling fan. But there are limits to how well they can work.
"The biggest thing is being able to evaporate the sweat off your body," says Cecilia Kaufman, director of occupational safety for the Korey Stringer Institute at the University of Connecticut.
In theory, a fan can boost your body's evaporative cooling process by speeding the flow of air over your skin.
"The problem is when it's hot and humid, the sweat does not evaporate as quickly off your skin," Kaufman says. "So that takes away your body's ability to really cool."
Surface area is key to effective cooling
For evaporation to work well, it helps to expose lots of skin.
"The best way to cool down would be basically to take all your clothes off, expose the entire body to the air and let all of the sweat evaporate," says Chris Tyler, a researcher in environmental physiology at the University of Roehampton in London. "But you'd get arrested," he adds with a laugh, "so that's not a recommendation."
In contrast, a neck fan can only affect a small part of your body. It might feel nice to use one, even if it's blowing humid air. In part, that's because there are a lot of thermal receptors on the face and neck, making them very sensitive to heat.
In general, we shouldn't view these neck fans as a type of treatment, Tyler says.
"It's a bit like playing sport with a painkilling injection," he says. "The issue is still there. It's just that you can't detect it for a little bit."
As a result, Tyler and Kaufman say, the small fans likely do more to make us feel cooler rather than actually lowering our body temperature — which could raise the risk of someone over-exerting themselves without realizing how the heat is affecting them.
But they also note that research is ongoing into improving ways of cooling the head and neck, as well as using cooling garments like hats and neck gaiters in hot environments.
Taking a neck fan for a test whirl
Down at the National Mall, I'm a bit skeptical when I first put my fan on. After all, the midday air is still and scorching. The flags that ring the Washington Monument's base are drooping and listless. (I feel you, flags.)
But as it starts to blow air on my ears and head, this little doodad does seem to make my time riding and walking a bit more bearable. I'm aware that I might look like an extra from a low-budget sci-fi movie with this thick, plastic device looped around my neck. But it doesn't feel too heavy or obstructive. And while I don't have long hair (or, let's be real, much hair of any type), it's worth noting that many of the fans are bladeless, so they're less likely to get entangled.
I roll down past the Reflecting Pool to the Lincoln Memorial. Along the way, I notice that when the neck fan is set to maximum power, the sound of the motor can be a distraction. At the bottom of the memorial steps, I run into Jeffrey Pagulong, who's visiting from Boston. He and his son Christof, 12, both wear neck fans.
"It's really hot," Pagulong says, standing in the blazing sun. "And wearing this fan kind of helps a lot, it cools down your head, so it helps" to ease the heat from walking, he adds.
I ask if the sound bothers him.
"The noise is OK. You can hear the fan, but it's fine. The noise is much better than the heat, you know? I can take the noise, but not the heat."
In my informal survey of the Mall, I spot more people using old-fashioned parasols than newfangled fans. It turns out a street vendor has been doing brisk business, selling yellow and red umbrellas for $10. One customer was Galilee Maldonado, 16, visiting from Texas.
"I bought it yesterday from a lady, but I really liked it," she says.
Like a neck fan, the parasol might not do much to lower her core temperature. But it's making Maldonado, who says she was surprised by the heat in Washington, feel better.
"It's helping me cope with this weather," she says.
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