Inspiratory muscle training: breathing training with a device

What is inspiratory muscle training?

Your diaphragm and the muscles between your ribs are skeletal muscles, like the ones in your arms and legs, and they get stronger when you make them work against resistance. An inspiratory muscle trainer is a small mouthpiece with a spring-loaded valve. The valve only opens when you breathe in hard enough, so each breath in is like lifting a weight. Breathing out is free.

Most trials use a short, hard session: 30 breaths at a setting that feels tough by the end, once a day. In clinics, a physiotherapist measures how hard you can breathe in (your maximal inspiratory pressure) and sets the trainer to a percentage of that. At home, most people start low and increase the setting every week or two as it gets easier.

Who is it for?

• People with COPD or another lung condition whose breathing muscles are weak, ideally with guidance from a respiratory physiotherapist.
• Runners, cyclists, rowers and other active people who want to improve endurance.
• Blood pressure: an interesting early finding, but not yet a treatment. Keep taking any blood pressure medicine you have been prescribed.

What the research shows

COPD. A meta-analysis of 32 randomised trials found inspiratory muscle training made breathing muscles stronger, eased breathlessness, improved walking distance by about 32 metres in six minutes and improved quality of life. A 2018 review agreed, but found it added little when people were already doing pulmonary rehabilitation. The largest trial, of 219 people with COPD and weak breathing muscles, found that adding it to rehabilitation made their muscles stronger but didn’t improve their walking distance more than rehabilitation alone. On its own it helps; on top of a full rehabilitation programme, the extra benefit is small.

Sport. A review of 46 studies in healthy people found breathing muscle training improves endurance performance, with less fit people benefiting most. A review of 21 trials in athletes found improvements in time trials and endurance tests.

Blood pressure. In a US trial, 36 adults aged 50 to 79 with above-normal blood pressure did 30 breaths a day, six days a week, for six weeks, at a high setting or a very low dummy setting. Systolic pressure in the high-resistance group fell from about 135 to 126 mmHg, and most of the fall was still there six weeks after they stopped. Their blood vessels also worked better. It is one small trial, so we treat it as promising rather than proven.

Overall we grade inspiratory muscle training as moderate. See sport and fitness and breathing exercises for COPD.

Common mistakes

• Setting it too low. If 30 breaths feel easy, your muscles aren’t being trained. The last few should be hard work.
• Setting it too high at the start. If you can’t open the valve, or you feel dizzy, turn it down.
• Breathing in slowly. Each breath in should be sharp and strong, as fast and full as you can.
• Blowing out through it. The training is in the in-breath. Breathe out slowly and gently.
• Expecting quick results. Strength builds over weeks. Most trials ran for six to eight weeks or longer.

Make it easier or harder

• Easier: split the 30 breaths into sets, such as 5 sets of 6 with a minute’s rest between, and start at the lowest setting.
• Harder: increase the resistance in small steps whenever 30 breaths become manageable. Some programmes use two sessions of 30 breaths a day.