Powerbreathe K5 – Just in

Test it yourself at the London Bike Show

Powerbreathe make devices for strengthening your intercostal muscles, which expand and contract your chest when you breathe. The company say this can help you breathe in more oxygen and exhale more carbon dioxide, thereby increasing the size of the ‘pipe’ in one step of the fuel turnover process.


Whether that’s going to matter to a cyclist is debatable, but we’re certainly up for testing it.

It works by using a mouthpiece attached to a variable valve, which can add resistance to your breathing compared to plain air. As you get stronger, you can adjust the resistance to suit. It’s used in the medical world for treating people like asthmatics to improve their lung function.

We were given a demo of their latest product, the Powerbreathe K5, which at £450 is the top of the range digital model. Why so pricey, when you can buy a basic Powerbreathe for £30? It’s about feedback. The K5 (and the yet to be released K4) are the only models that you can plug into a laptop via a USB cable. This means you get direct feedback as you do the workouts and tests, which is pretty important in knowing whether you’ve improved. The K1-K3 models (£250-£300) also give you feedback, but it’s limited to the small screen on the device. The much cheaper analogue models don’t give you any feedback at all.

PowerBreathe k5: powerbreathe k5
John Whitney/BikeRadar

The first thing we did was a test to see how strong our inspiratory muscles were (inspiration comes in different guises). This involved breathing in as hard as we could through the mouthpiece of the device. The result was 100 cmH2O (centimetres of water ‘lifted’). We could also see our peak inspiratory flow and volume, power of the breath in watts and work done in joules. Pretty cool, although we’d been warned that a German doctor/triathlete who’d been using one of these had top scored with 221 cmH2O. Oh well.

A second attempt got us up to over 120, so we then opted to do a 30 breath workout. This takes a few minutes and it’s recommended you do it twice a day for optimal improvement. After the first few breaths, the device will set a resistance level for you to complete the remainder. You can see how good each breath is as you go, and you get enough time to recover between each one so that you don’t get too lightheaded. At the end, you’ll have averages of the various metrics – something to base your next workout on as a benchmark.

We repeated our peak inspiration test afterwards and managed to hit 146, which clearly shows that technique is the first thing you learn before strengthening the muscles, which takes much longer. You’ll be able to try it for yourself at the London Bike Show – buy your discounted tickets here, code ‘radar’ – next January, by which time we’ll have tested it to see if it does help us on the bike. And if you visit the BikeRadar Training Hub at the show, you’ll be able to meet Alison McConnell, the sports scientist who invented the PowerBreathe who will be giving a talk at the show.


The Powerbreathe K5 comes with its own charger, USB cable, cradle, separate mouthpiece, software and cleaning tablets, and it can be disassembled for easier cleaning. For more information, visit www.powerbreathe.com