The newest ways to stay cool while you sweat

Summer keeps getting hotter, but record temperatures aren’t keeping runners from their daily jogs or fall marathon training. A new wave of high-tech apparel aims to help them stay cooler and more comfortable through the heat.

For decades, the way to stay cool while exercising was simple: wear less clothing and make what you did wear light and loose. Now, the world’s biggest performance brands and a wave of smaller challengers are betting on a new approach: “active cooling technology”—fabrics, constructions and materials designed to lower the temperature at the skin’s surface.

Robert Higgins, who researches heat and hydration during exercise at the University of Connecticut’s Korey Stringer Institute, advises that high-tech clothing is fine to try, but isn’t necessarily better than letting your own sweat cool your skin. And no matter what you’re wearing, he says, anyone exercising in extreme heat needs to stop if they notice a higher heart rate, excessive fatigue or muscle cramps.

Here’s how the new pieces work, plus feedback from runners who’ve road tested them.

Cool Head

The graphite cubes in the cap soak up water and spread it across a larger surface area than your forehead so it evaporates faster, making you feel cooler, according to research.

“My Omius hat saved my race at last year’s Berlin Marathon [in September], where temperatures were unseasonably high. I brought a water bottle to the start line and wet the hat right before the gun went off, then dumped water on the hat at every water station. I still faded, but I ended up finishing with my best result in the three times I’ve run that course. ” —Brian Schroy, 37, Boulder, Colo.

Cold Neck

The zippered pocket in the bandanna holds up to 2 pounds of ice that drips out through tiny holes in the neoprene fabric as it melts.

“I’ve found it works better than a regular bandanna filled with ice. The shape sits better on the shoulders and back and there’s very little bounce. It’s a lot more comfortable around the neck—it only kind of feels like I’m being strangled.” —Mike Ko, 46, Crystal Lake, Ill.

Air-Conditioned Core

Tiny, tapered holes in this long-sleeve shirt channel air onto the skin, with larger cutouts in high-sweat spots to keep the shirt light and chafe-free.

“I recently did an interval workout in 85 degrees while wearing this, and it felt like there was a little layer of cool air between the fabric and my skin. It was especially noticeable when a breeze would come by—it felt like someone turned just a little bit of A/C on around my body. I even took it off for a rep to see if shirtless would feel better and nope, it felt cooler when I had the top on.” —Alex Burks, 29, Westminster, Colo.

Ice-Cold Arms

Wet, then wring out and wave around these arm sleeves before snapping them on—research shows they provide a sensation up to 30 degrees below body temperature.

“I bought these sleeves because I’m responsible for leading marathon training runs, so I don’t have the luxury of dropping out if I overheat. I soak them in cold water before the run, and in my experience they provide an appreciable cooling effect once activated and stay cool long enough to make a meaningful difference for over two hours. They also do a great job protecting my arms from sunburn.” —Steve Greenspon, 56, Chicago, Ill.

Fresh Legs

These two-in-one shorts layer a lightweight shell over a liner that’s constructed from cloud-shaped fibers which boost the surface area sweat can evaporate from.

“The lining fabric is extremely light and silky, and once it’s wet, that material cools your sweat and becomes like a second skin. It also becomes transparent (you can see tattoos through it), so you really need the light over short to prevent you from looking completely naked. I think it actually worked.” —Thomas Neuberger, 55, Baltimore

The Verdict

Do you need a $150 cooling shirt or a $234 cooling cap when a splash of water and a light T-shirt might get you most of the way there? Runners describe a noticeable effect that can be worth it if you’re logging serious miles in the heat, but the gear is optional, not essential. “Skin exposure is the best means for your body to cool,” says Higgins. For those who aren’t comfortable running shirtless or want sun protection, a lightweight, sweat-wicking top is a happy medium.