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Home / Features / I tried this $1000 machine that promises to use cold therapy to boost exercise performance; it doesn’t

I tried this $1000 machine that promises to use cold therapy to boost exercise performance; it doesn’t

The CoolMitt is an oversized glove that cools your muscles to boost your exercise performance. Or, at least it's supposed to

Using the CoolMitt

When it comes to exercise gadgets, there’s all manner of tech that claims to help you out. You’ve got all manner of fitness trackers that are targeted for different activities. These days, there are even devices that claim to read your blood sugar and tell you want to eat. I’m no stranger to a quirky fitness gadget, and have previously plunged needles into my arm in the name of nutrition. This time around, I’m trying this $1000 machine that promises to use cold therapy to boost exercise performance.

Water, electricity, and cold. It doesn’t sound like a fun mix if you ask me. I’m imagining a good 10% risk of electrocution here. The things we do for tech testing, eh. So, how does the CoolMitt actually fare?

What is the CoolMitt supposed to do?

So I’ve had to brush up on my biology to understand the science behind the CoolMitt, and I’ll try to break it down as simply as possible here. As is fairly obvious if you’ve ever done any sort of exercise, you get hot and fatigue during a workout. That’s because your muscles release heat while you exercise as they burn energy.

As you continue through your workout, this internal heat starts to build up. Your body doesn’t like this so much, so is wired to start to slow your muscles down – so they don’t overexert. That’s when you start to fatigue. You can lift less, can’t hold your plank for as long, or can’t run as fast as you should. You’re body’s limiting itself to some degree. Of course, you’ve still got physical barriers, etc – you can only do so much. But the CoolMitt reckons it can solve your body’s self-imposed limits.

CoolMitt in use

It’s essentially a large glove, that looks like it would be better suited for the BFG. In the closed environment, the CoolMitt rapidly passes chilled water over the palm of your hand. Some clever scientists figured out that your palms are one of the body parts that expel the most heat – around 5 times more than other parts of your body. As it cools down the blood in your palm, this cool blood gets sent back to your heart to be pumped around the body. So, by passing cold water over your palms, the clever cooler can chill down your muscles even faster.

How does it work? You fill up the tank with ice and water. There’s a big copper coil in the tank (trust me, my electrocution fears shot up a good 30% when I saw this), so cool down the water in the pipes. These pipes connect to the oversized glove (known as the mit), which is where you’re supposed to shove your hand. It promises “delayed fatigue, improved endurance, increased training gains, and elevated overall performance.” The only thing left to do is fire it up.

Does the CoolMitt boost exercise performance?

To say I’m slightly sceptical of the CoolMitt going into it would be an understatement. There’s always a new gadget to hit the scene that promises to boost your workout performance. But, hey, there’s science behind it, and I’ve been proven wrong before. Just look at electric stimulation. So with the device filled with ice and water, I let it run for a few minutes to cool down before plunging my mit into the… well, mit.

The first thing that confused me was that the cooling pack was on the back of my hand – not the palm. For all the science about the palm of your hand this seemed… weird. But you’ve got veins in the back of your hand, so I went with it. And to make things clear, this wasn’t user error. The mit is shaped, so you can only put your hand in one way. Interesting, but I continued.

With my hand inside the CoolMitt, the next thing to surprise me was the temperature. Or, more specifically, how not cold it was. Filling it up with ice and water, I expected this thing to be like plunging your hand in the snow. It was far from it. It was barely cooling, in fact, and I felt like my hand was heating the water up more than it was cooling me. You’d get a colder hand running it under the cold tap, significantly.

But none of that matters if it works, right? To try and test this thing fairly, I did a test set of reps with a dumbbell. It was at my max weight for a comfortable set, and I squeezed out a solid 12 reps – pretty standard per my program. I probably could have eked out a thirteenth, but it would have been poor form, so not worth it. I waited an hour to let my body completely rest, and then repeated the reps with the CoolMitt ready to go.

While the CoolMitt was cooling down, I boshed out the 12 reps again. As expected, no change here, as I had ample time to rest since I last lifted these. Immediately, I plunged my hand (the right arm, if you’re interested) into the CoolMitt. I left it in there for the recommended 2 minutes, and then pulled my arm out. I went straight back to the reps, and managed another 12. Not too unexpected with such a large rest time.

I went through it all again, and managed 11 reps. Tried again and down to 10. One last time and down to 8. In my regular workouts, I’d scale these down at a similar rate – keeping at my max weight. So these numbers weren’t higher than usual. In essence, it doesn’t look like the CoolMitt was doing anything to improve my performance here.

Is it all a load of cold air?

Going through a lifting set, it didn’t look like the CoolMitt make a lick of difference to my exercise performance. Perhaps it would require a more thorough set to see more minor differences, but that’s not what’s being sold here. And if cooling down your hands is the secret to lifting more – why not run your hands under some cold water?

This definitely seems like a fitness fad. As I’m not a scientist, I’m not prepared to conclusively say the CoolMitt does nothing. It sure looks that way, but maybe you’ll notice small effects in a larger workouts. But what I can say, is that this isn’t something you should add to your basket. $1000 for a cold water machine is a massive ask. Just put your hands under the tap, please.

Profile image of Connor Jewiss Connor Jewiss


Connor is a writer for Stuff, working across the magazine and the Stuff.tv website. He has been writing for around seven years now, with writing across the web and in print too. Connor has experience on most major platforms, though does hold a place in his heart for macOS, iOS/iPadOS, electric vehicles, and smartphone tech. Just like everyone else around here, he’s a fan of gadgets of all sorts! Aside from writing, Connor is involved in the startup scene. This exciting involvement puts him at the front of new and exciting tech, always on the lookout for innovating products.

Areas of expertise

Mobile, macOS, EVs, smart home

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