Good reasons to doubt us.

You make the heat yourself. Hard efforts turn energy into work and heat, so it arrives whether the room is warm or cool. The room decides how easily you shed it, and across repeated efforts most people make heat faster than they clear it. What you feel as fatigue is partly that.

Ice numbs the skin, moves less heat from the core, and loses its cold fast. A can from the cooler starts too cold, then warms, and only the patch under your hand works. KYLA sits around 14 °C across the whole surface, for the whole rest, and the next one.

During hard repeated efforts you make heat faster than sweat can clear it, the extra builds up, and output drops. KYLA gives the palms somewhere to send that heat, in the minutes you are resting anyway.

Palm skin is packed with vessels built to move heat. During exercise in the heat, palm skin gave off more than five times as much heat as ordinary skin (Heller and Grahn, 2012). One rest moves a little. Rest after rest, it adds up. Sixty to ninety seconds, both hands, every rest: protocol in How it works →

Skin gets used to cold quickly, so the feeling fades. Heat keeps leaving as long as blood flows through the palm and the surface stays cooler than you. The one sign to watch is numbness: then it is too cold, and the vessels start to close.

Heat moves from warm blood to a cooler surface, and it keeps moving as long as blood flows and the surface stays cooler. There is no tolerance to build. What nobody has yet is years of long-term data, and when it exists we publish it.

Core temperature climbs with effort in a gym as well as in a hot room, and the handles take heat out either way. The sprint study was run at 32 °C.

Settled: heat leaves the body quickly through the palms, in decades of peer-reviewed research, and in most trials athletes did more work. Not settled: how much of that is the cooling itself, and for which sessions. Results are mixed, and Published research keeps a section for findings that cut against us. An independent study is being designed now, and testing starts in January 2027.

Until independent results exist, every performance number we have is ours, so they live in Our testing so far with conditions and sample sizes, not in our headlines, and you can request the raw data. A result that cuts against us goes to Published research with the others.

In the newest strength study, fourteen trained men lifted 15% more in total across their sets with palm cooling than with a placebo, and 22% more than with nothing. Wang et al., 2026 → One study, and a small one. Our own testing tracks markers that are harder to fool than how you feel: how fast heart rate comes back down between efforts, and blood lactate at the same pace. Until an independent study of KYLA reports, hold your judgement.

Deliberate heat training has real, documented effects, and if that is the purpose of the session, do not cool it. Most sessions have a different purpose: quality work at full output. You decide which sessions are which.

Much of the published pre-cooling evidence was built on them. A vest cools a large area of skin and is worn through activity. KYLA is built for the rest between efforts, through the palm. We cite the vest research in Published research, including where it supports approaches other than ours.

Researchers have known the mechanism for decades. The lab rigs that showed it ran on pumps and water baths, and never made it to a gym floor. Several companies, us among them, are building handheld versions now. Whether ours works as well as the lab did is for the athletes and the independent testing to say.

Seventy elite athletes are training with them now, before the First Run ships. We do not pay for opinions, write scripts, or require posts. An athlete who takes a pair and never mentions us stays in the program. Some of the most visible use has come from athletes we have no relationship with.

The newest strength study used fourteen trained men, not professionals. Wang et al., 2026 → You are already doing the work: the gym, the intervals, the rounds. This helps you get more out of the session you were going to do anyway. Whether that margin is worth it is your call, and you have 90 days to find out.

KYLA is built for the rest between efforts: sets, intervals, rounds, the break between games. A steady run or ride without stops has no slot for it. If your training has rests, it fits there.

Eight trained women did more total work on the bench press with cold palms between sets than with neutral ones. Kwon et al., 2015 → Twenty female college athletes completed 10.3 successful sprints with palm cooling in the rests, against 6.0 without. Wrabley et al., 2025 → Small studies, both.

In two studies, cooling at half-time kept second-half sprint power higher. In one, soccer players cooled hands and forearms at half-time. Iwahashi et al., 2023 → In the other, active men in a 32 °C chamber cooled their palms in the rests, and second-half average power was 12.7% higher than without cooling. Hu et al., 2026 → Both were in the heat, and both were men.

Between efforts you catch your breath, drink, and wait. KYLA lives in that slot: pick up, hold, put down. It needs no attention while you hold it and adds nothing to the work. After a few sessions it becomes what your hands do while you rest.

329,50 kr today, the rest when we ship. Cancel any time before it ships and you get it all back. Train with it for 90 days. Full refund if it's not for you. Meanwhile the athletes using KYLA are named, and our test data is published with its limitations stated.

Most cost less because they are a cold mass that warms in your hand, or a battery device that moves little heat per palm. KYLA took two years and more than forty builds to keep taking heat out, rest after rest, with no refills, no batteries and a three-year warranty. And you do not have to take our word for it: train with it for 90 days, and if it has not earned its place, you get all of it back.