man using powerbreathe plus and lady using powerbreathe classic light resistance level and woman using Plus light resistance level

Are you unsure which resistance level might be best for you? Well, in this blog we look at comparing the levels of the POWERbreathe Classic and POWERbreathe Plus Inspiratory Muscle Training (IMT) devices. And, you can find out more about How To Use The Classic And Plus in our blog.

Resistance Levels

The POWERbreathe Classic series and POWERbreathe Plus series are ‘pressure-threshold’ devices. There are three models available in each series:

  • Light Resistance – adjustable
  • Medium Resistance – adjustable
  • Heavy Resistance – adjustable

Each device uses a calibrated, spring-loaded valve to create the resistance to your in-breath. The valve will only open to allow you to breathe in through it, if you are able to generate enough inspiratory pressure. Your inspiratory pressure is measured in centimetres of water, or cmH2O. This provides an accurate measurement of training load. When you generate enough power with your breathing muscles, the spring-loaded valve will open at the “pressure threshold” you set, hence the name.

What is cmH2O?

cmH2O is short for centimeters of water (two hydrogen (H) atoms and one oxygen (O) atom). It is the unit of pressure most commonly used to measure breathing on respirators and ventilators. It is also the unit of measurement for monitoring athletic performance and controlling respiratory conditions in medical and physiological applications.

Which Resistance Level?

Light Resistance (LR)

The POWERbreathe LR models train your breathing muscles using a calibrated ‘Light Resistance’ inspiratory load. It is an entry level model for those new to breathing training and for those with breathing problems (e.g. asthma) and features an adjustable ‘light’ training load. The range between each training load (cmH2O) on the LR models is quite small, which makes it more manageable when you increase the resistance, as your breathing muscles become stronger.

Load Setting Range


Medium Resistance (MR)

The POWERbreathe MR models train your breathing muscles using a calibrated ‘Medium Resistance’ inspiratory load. The range between each training load (cmH2O) on the MR models is broader than that offered by the LR models, making training more of a challenge when you increase the resistance as your breathing muscles become stronger. Therefore, these models are more suited to those who are moderately fit, to very fit.

Load Setting Range

Heavy Resistance (HR)

The POWERbreathe HR models train the breathing muscles using a calibrated ‘Heavy Resistance’ inspiratory load and offers the widest range between each training load (cmH2O). Because of the large increases in cmH2O, training with the HR device is the most challenging. We therefore only recommend those who have reached the maximum load on the Medium Resistance model consider training with the POWERbreathe HR.

Load Setting Range

Training Progress

The POWERbreathe Classic and Plus IMT devices are adjustable, whichever level of resistance you use. They are adjustable to enable you to progress gradually, as your breathing muscles adapt and become stronger. You simply adjust the device using the load adjustment knob, and with every quarter turn you are increasing the difficulty, or ‘load’. To keep a track on your progress, it is worth recording your training level over a period of time, using a Training Diary.