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HOW IT WORKS
Why your body holds back as it heats up, why your palms are built to let heat out, and how KYLA uses that.
Every study below is published, and none of them is ours.
01 THE PROBLEM
Heat does not weaken the muscle. It lowers how much of its output your nervous system uses.
It does not happen at one temperature. The warmer you get, the less of it you can use.
The same muscle, a maximal contraction
Nybo and Nielsen 2001 · 14 men · not a KYLA study
02 THE PRINCIPLE
Energy cannot be created or destroyed, only turned into something else. Every rep and every stride turns it into movement, and about 80 percent of it into heat.
That heat slows you down, the same way it slows a machine.
A laptop
Runs hot. Slows itself down.
An engine
Overheats. Cuts its own power.
You
Heat up. Your body holds back.
For both, the answer is the same: give the heat a fast way out. Machines have a cooling industry. Humans do not. We are building it.
03 THE MECHANISM
Nearly all of your skin is insulation. The palms are the exception. Your palms have shortcuts between artery and vein. They feed no tissue and their only job is to move heat. They are called heat vessels (AVA*).
They stay shut while you are cool, and open as you warm up. Then the heat wants out, but air carries it away slowly. How fast it leaves depends on what you hold: how well it conducts heat, and that it stays cooler than your skin.
You already use this route. You cup cold hands to breathe on them, and kick a foot out from under the blanket on a warm night.
*Arteriovenous anastomoses. How they work: Walløe, 2015. Temperature.
Inside your palm
You are cool
The heat vessels stay shut. Heat stays in.
You are warm
The heat vessels (AVA) open, a shortcut from artery to vein, and the heat wants out. Air carries it away slowly.
Warm, holding something that conducts heat
It pulls the heat out fast. Colder is not better. More contact is.
What you hold, compared with your skin
Close to skinLittle heat moves.
Cooler than skinThe vessels stay open. Heat moves fast.
Far colderThe vessels shut. Heat stays in.
04 SKIN OR CORE
The palm has a door for heat. How big is it, next to the rest of your skin?
Heller and Grahn, 2012. A review by the originators of palm cooling.
Cold on the neck feels like a lot. It chills a thin layer of skin, and the core warms it back up. In the palm, core blood comes to the surface and the heat leaves for good.
One honest limit. Palm cooling is a targeted tool, not whole-body cooling. If someone is genuinely overheated, cold water over the torso and limbs is still the fastest way down.
Comparing actual products? See what each maker publishes: weight, run time and price.
05 THE ENGINEERING
Holding something cold does not mean heat is leaving you. Two things decide it: how fast the surface takes heat, and how long it keeps taking it.
What you hold is the same.
What the heat meets is not.
A SOLID COLD OBJECT
55 cm²
55 cm²
The heat only meets what you touch.
KYLA
55 cm²
557 cm²= 10 palms
The heat meets ten times more surface.
Ten times more surface than your palm covers.
10× CONTACT
Behind your palm, a patent-pending internal system spreads the heat across 557 cm², so the surface under your hand does not warm up and quit.
1 · How fast it takes heat
How long you hold it and how cold it is: How to use →
06 THE RESEARCH
Independent research, none of it funded by us. These are the four results we lean on. Every study we found, including the ones that found no effect, is in Published research.
WHAT IS SETTLED, AND WHAT IS NOT
SETTLED, IN INDEPENDENT STUDIES
The route in the palm exists.
Cooling it between efforts lets athletes do more work, in most trials.
Too cold closes it.
STILL OURS TO PROVE
How much a pair of KYLA handles adds, in your session.
An independent study is being designed now, and testing starts in January 2027.
Our own testing so far: seventy elite athletes are training with it, and nineteen have sent heart-rate data. Small samples, not yet significant.
The studies in full, how we test in training, and good reasons to doubt us.
KYLA Performance™ is a pair of handles built around the heat vessels on this page. What it is built to buy you is the end of the session: the sets, reps and rounds you would otherwise have cut short.
Reserve a pair, ships 10 November 2026$475.00 · $47.50 today · 90-day returns