Just Chillin'
When the Mercury Soars, Can Science Help You Keep Your Cool?

By Buzz McClain
Special to The Washington Post
Tuesday, August 29, 2006

Yes, it's only mildly hot and muggy now, but last week's 90-plus-degree temps could be lurking around a steamy corner, and you should be ready to defend yourself. To that end, we spent the hottest days of August trying to be cool, for you.

That's cool, as in temperature. We looked anything but, what with all the refrigerated bandanas, hoods, vests and water-filled shirts we sported. You could call it a kind of fashion show (a sorry kind) for cryotherapy -- the therapeutic use of cold.

The idea behind cryotherapy apparel is to maintain the temperature inside your body at 98.6 degrees or thereabouts, says Christopher Ingersoll, a professor of sports medicine at the University of Virginia Health System. A walk outside in the swelter, says Ingersoll, can raise that internal temperature and produce discomfort. If you exert yourself, core temperature can go much higher, threatening the body's natural cooling mechanisms of blood and sweat. When it rises to 105, "we get worried," Ingersoll says. At 108 degrees, "you start to denature protein in your brain. You're cooking the brain is what it amounts to."

That explains that funny smell.

But does the dorky garb work -- and is it practical? With Ingersoll's help, we aimed to find out. Here's what we tried:

· Chill Factor Performance Bandana ( http://www.chillfactorperformance.com/ )

Move over, Willie Nelson. You may look cool in your headband but we're chillin'.

"Inside is a polymer [actually, a strand of polymer molecules] that absorbs water like a sponge," says Chill Factor Performance vice president David Kesner. Soak the cotton bandana ($5) in cool water for 30 to 45 minutes, then refrigerate for about 20 minutes and wrap around your neck, or tie it like a headband. "If it's 100 degrees outside, [the bandana] might hold at 55 or 45 degrees for up to 20 minutes, then back to 15 to 10 degrees below air temperature," said Kesner. The water in the bandana "will eventually evaporate, so you just throw it back in the water."

We tried it, first as neckwear, then as headgear, on one of the month's hottest days. The cooling was immediate, without drips or wetness, but the half-hour of maximum effectiveness seemed fleeting. To make it last longer, you'd need to rotate several bandanas in and out of a cooler or fridge; yeah, that could limit mobility some. Still, there's no question that the Chill Factor product delivers more relief than a water-soaked regular bandana would. But, warns Ingersoll, leave dried ones on your body and they become "another layer of clothing that impedes your ability to cool due to the evaporative effects of sweat."

· Reversible Evaporative Cooling Vest by Industrial Savings ( http://www.industrialsavings.com/ )

We pulled the canvas-colored vest ($34.99, on sale from $69) out of its bag and couldn't figure up from down. The hook-and-loop straps took a little untangling (and still we didn't know which way was inside out). It looked like it might inflate into a raft; instead, it expanded into something a nattily attired highway flagman might wear.

After soaking the garment in cold water (the greedy polymers in the lining lapped it up), we strapped it on. It felt cool but not wet; the added pound of weight was hardly noticeable. The cool effect lasted more than 50 minutes, or else we just got numb.

Industrial Savings spokesman Dave Ridgley claims buyers include companies anxious "to prevent heat stress problems with their employees. There's nothing worse than having your employees drop over in the middle of the day." We had nothing to say.

Would this big vest get you to the office sweat-free? It might. The gizmo's size and where it's worn -- around your trunk -- work in its favor. "Cool the blood that circulates into the core, and that will decrease temperature in the core," says Ingersoll. We can't help you with the stares.

· Chill Factor's Rehab Hood ( http://www.chillfactorperformance.com/ )

Polymer fibers sewn into the lining provide the cooling power for this oversized hood ($60), created to help firefighters bounce back after training or firefighting. We felt like Eminem with the gray hoodie over our head, ears and eyes. The hood did indeed seem to keep our head at least 20 degrees below the 97 recorded on weather.com. The effect was, if anything, too strong. It might have been more comfortable if we had actually been doing something beforehand, say, coming in from a run.

Another drawback: There's no obvious way of keeping it on your head if you move a lot; there are no drawstring or snaps.

Alas, cooling the head, while it feels refreshing, misses the mark. "The best points are behind the neck, under the arms and in the groin," says Ingersoll. "Those are going to be areas where you'll have some fairly large blood vessels that will cool you down the quickest."

The groin? We couldn't find a single groin cooler. "I think comfort level may play into that just a little," Ingersoll surmised.

· The Cool Shirt ( http://www.coolshirt.net/ )

It looks like nothing more than a space-age tank top -- a sleeveless cotton shirt. But in Iraq, a few comparatively lucky soldiers serving in tanks and Humvees use it to keep from frying. Recreational and industrial applications have scarcely been tapped, though, according to Cool Shirt Personal Cooling Systems co-owner Rich Shafer. The systems start at $350 and top out at $2,500. (The prices vary according to how many shirts would be connected to the cooling unit.)

The premise is intuitive: Fill a cooler with ice water and connect it with a hose to a cotton shirt laced front and back with 55 feet of medical-grade tubing; use a pump to circulate the water. Stay connected as long as you like or, if you need to be free from the icy umbilical cord, plug the shirt in only as needed. In either event, keep adding ice to the cooler.

We filled the icebox, donned the shirt, picked up the cooler and tried to take a walk around the neighborhood at noon. We didn't get far -- the extension cord for the pump gave out, the cooler weighed about 10 pounds, and we felt a bit like an early astronaut carrying his oxygen pack. Still, the distribution of the cold water was even and we couldn't feel it circulating.

Ingersoll's take: These shirts may be attractive "if you're going to sit in a hot car in the desert," but they may be a bit much for the office set.

· The Sharper Image Personal Cooling System 3.0 ( http://www.sharperimage.com/ )

You see these $29.95 chokers everywhere. Worn clamped around the neck like a "Star Trek" accessory (or maybe a dog collar), this device has a small fan that blows "evaporative water" on you. The story goes that inventor Ted Strauss, now a shamanic spiritual healer, got the idea after noticing hot people putting cold beer cans on the backs of their necks. The gizmo weighs 14 ounces when the water reservoir is filled.

Alas, our trusted mailman Morgan wore one during the hottest week of August and wasn't impressed.

"I don't wear it anymore, and I wouldn't recommend it," he said.

· Bonus bit: Even though being encased in a block of ice on the hottest day sounds like a staggeringly frigid way to bring down the core body temperature, it's not. In fact, "it's rather hot in there," says James Randi. Randi, aka the Amazing Randi, is a well-known magician and debunker of the paranormal. Several times in his career he's been encased shirtless in an ice coffin in what he calls a survival stunt. As a finale, he's freed by ice axe. His record for endurance: 1 hour, 44 minutes.

"Here's a little secret: The air around you is quite warm," he says. "The stunt is not to keep warm but to keep cool. It gets quite hot in there. And the cold drips of water that hit your body are like ice-cold bullets. I thought that might surprise you." ·

Buzz McClain last wrote for the Health section about the Genographic Project of the National Geographic Society. Comments:health@washpost.com.