Incentive Spirometers and Home Spirometry: What They Measure and Do Not

Three devices, three jobs

Incentive spirometers

MedlinePlus says a provider may recommend one after surgery or when you have a lung illness such as pneumonia, and that it helps you take slow deep breaths. It may also be used to help people with COPD exercise their lungs. [1] The patient instructions describe sitting up, breathing in slowly so a marker rises, holding a pillow against a surgical cut for comfort, and removing the mouthpiece and taking normal breaths if you feel dizzy or lightheaded. [1] Those instructions also include a short pause at the end of the breath. This site does not teach breath-holds, so use the exact instructions your own care team gave you, and ask them if you are unsure.

What trials found:

1. Upper abdominal surgery

   Insufficient evidence of benefit

   A Cochrane review of 12 trials (1,834 people) found low-quality evidence of no clear benefit for preventing lung complications, and the trials were poorly reported. [4]

2. Lung resection (chest) surgery

   Promising but limited

   A 2023 review of 5 randomized trials and 3 cohort studies (10,322 people) found shorter hospital stays and fewer lung complications with incentive spirometry. [5] The cohort studies were retrospective, so this is weaker than randomized evidence.

3. Home use for healthy people

   Insufficient evidence

   Proper evidence not found. We searched PubMed for incentive spirometry trials and found surgical settings, not healthy home use.

In plain terms: use after surgery is common, and the best evidence is mixed. Ask your surgical team whether and how often to use one.

Clinic spirometry and what it measures

The NHS says spirometry is used to look for conditions such as asthma and COPD. It requires forceful, repeated blows into a device under professional supervision. [2] It is not safe for everyone: the NHS lists a chest infection, certain heart problems, uncontrolled high blood pressure, a recent heart attack or stroke and some recent surgery. [2] You may feel dizzy or faint during or shortly after the test, though this should not last long. [2] A specialist looks at the results and sends them to your doctor. [2] Do not try to copy the test as a breathing exercise.

Peak flow meters

The NHS says a peak flow test measures how quickly you can blow air out of your lungs and is mainly used to help diagnose and check asthma. You may be asked to do regular tests at home. A doctor or pharmacist will show you how to do it correctly. [3] Peak flow scores differ by age, height, sex and time of day, and the NHS says to note what is normal for you and tell your nurse or GP if your score is lower than usual. [3] The test involves a hard, fast blow, so it is a measuring task, not a relaxation practice. [3]

What these devices cannot tell you

A single number does not show what is causing breathing trouble. The NHS says a low peak flow score could be a sign of narrow airways and you may need more tests. [3] Home devices do not replace a clinician's interpretation. For consumer pulse oximeters, which are a different device, see pulse oximeters and SpO2 estimates.

Access and cost

The NHS says a peak flow meter may be given on prescription or bought from a pharmacy. [3] We give no prices or coverage claims, because the sources we read do not. Talk to your clinician before buying a device.

Related reading

Breathing exercises for lung health and recovery, breathing exercises for asthma and when breathlessness needs medical care.