Spirometry

Spirometry measures the volume and speed of air you exhale to help assess how your lungs are working.

You breathe through a mouthpiece connected to a spirometer while a trained person coaches the manoeuvres. It can help investigate conditions that narrow or affect the airways, and it can be used to monitor change over time when interpreted with your symptoms and examination.

You will usually sit upright with a clip on your nose. After a full breath in, you seal your lips around the mouthpiece and blow out as hard and as long as you can. The manoeuvre is repeated because effort and technique affect the trace. In some cases, the test is repeated after an inhaled medicine.

Spirometry does not use radiation or needles. Forceful blowing can briefly cause light-headedness, coughing or chest tightness, so tell the tester if you feel unwell. The result is most useful when the blows meet quality standards and is considered alongside your history, examination and other tests rather than as a diagnosis on its own.

An unusual airflow pattern may lead to a discussion of possible airway narrowing or restriction and whether the test should be repeated. Asthma commonly presents with episodes of wheeze, cough, chest tightness or breathlessness, but spirometry findings must be interpreted in the full clinical picture. Your clinician may suggest inhaler therapy, further testing or follow-up measurements.

Good preparation and a strong seal around the mouthpiece matter. Ask when booking whether you should avoid smoking, heavy exercise, large meals or certain inhalers beforehand. Do not stop a prescribed inhaler unless you receive clear instructions from the clinician arranging the test.

A clinician may request spirometry for ongoing cough, wheeze, breathlessness or a known lung condition. COPD can present with persistent respiratory symptoms and reduced airflow. Bronchiectasis may involve recurrent chest infections and mucus production, while chronic cough has many possible causes; testing helps organise the assessment rather than settling every cause by itself.

Wear clothing that does not restrict deep breathing and bring your inhalers or an up-to-date medication list. The tester explains the breathing pattern, watches your technique and records several attempts. Afterward, you can normally resume your day. If a bronchodilator is used, the team explains when to restart your regular inhaler routine.

No recovery period is usually needed. Rest briefly if the repeated blows leave you dizzy, and tell staff if symptoms do not settle. Results may be discussed at the same visit or reviewed later, depending on why the test was arranged.

The forceful breathing manoeuvre can be unsuitable soon after some operations or during certain acute illnesses. Tell the provider about recent chest pain, coughing blood, severe breathlessness, eye surgery or any advice to avoid straining, so they can decide whether to postpone or adapt testing.

Depending on the concern, assessment may include a chest examination, oxygen measurement, imaging or another lung function test. Smoking cessation support can reduce ongoing smoke exposure. Inhaler therapy is selected only after a clinician considers the likely cause, technique and response to treatment.

Choose a provider that explains pre-test instructions, performs coached testing and offers a clinical interpretation. Seek urgent assessment for severe or rapidly worsening breathlessness, blue lips, chest pain, fainting or coughing blood.