Hi,

Have you ever had a harder day training or racing because it was hot out — or felt nervous about a big race because of the heat? If so, it's worth understanding what's actually happening to your body when the temperature climbs.

Think of your body like an engine: the harder you are working, the more heat you throw off — we're talking 5 to 15 times more than when you're sitting still. All that heat has to go somewhere, and your only real exit is through your skin and sweat.

When you can't shed it fast enough, your core temperature rises, and your body quietly flips from "let's perform" to "let's not overheat."

First it reroutes blood away from your working muscles and sends it to your skin to help you cool off. Your heart starts beating faster just to do the same job, and suddenly you're grinding to hold a pace that felt easy ten minutes ago.

In one study that put 105 elite athletes in a heat chamber, the heat alone chopped their time to exhaustion by about a quarter — at the same exact workload. It's not your legs that wave the white flag first. It's your core temperature.

The most powerful cooling system out there is the one you were born with — evaporation. When water or sweat evaporates off your skin, it physically carries heat away. Beyond your own built-in system, there's a wave of cooling tech worth trying to see what works best for you.

You've probably spotted these in ultras and IRONMAN races, the Omius Headband.

Here's how Omius works:

Water soaks into the porous graphite pieces, where it has 5x more surface area to evaporate from.

As that water turns to vapor on the graphite, it pulls heat straight out of the pieces sitting against your skin.

And because it's pure evaporation doing the work, it keeps going as long as the pieces stay wet and air's moving over them — no ice, no charging. It's a featherweight 50g, the pieces pop out and swap, and it's made for the athlete chasing every edge when it's hot.

One thing to know:

Omius isn't meant to lower your core temperature.

It's a local effect that makes you feel cooler — which can be the nudge that lets you push a little harder.

So does it actually make you faster? Kipchoge, Sifan Hassan, Hellen Obiri, and Bashir Abdi have all raced in it. That's not a lab result, but when the best in the world strap something to their heads, it's worth paying attention to.

Pro Tip: Omius only works if the pieces stay wet and the air's flowing. Re-wet it often — every aid station is a good habit — and that's the whole difference between the people who swear by it and the ones who shrug.

Looking for a less expensive option to try to see how your body adapts - try The Feed's cooling towel. 

We're down to limited stock, but this one works really well. It's built with Coolcore's Biomimetic Fiber Geometry — a fancy way of saying it wicks 44% better than a normal towel and dries 48% faster, with UPF 50+ sun protection built in.

Soak it, wring it, snap it, and cool off.

We hope this helps you feel a little cooler this summer.

-The Feed.