What should you know about FEV1 and asthma?

During spirometry, you take a full breath and blow into a mouthpiece as hard and fast as you can. FEV1 is considered with other measurements, your symptoms, examination, and how the result changes after a reliever medicine. A single result does not establish asthma by itself, and a normal reading does not explain every breathing problem.

Asthma symptoms can include wheeze, cough, chest tightness, and breathlessness. Allergic rhinitis, house dust mite allergy, infections, exercise, smoke, and other irritants may affect symptoms or test timing. Your clinician may repeat testing when symptoms and the first result do not match.

Follow the clinic's instructions about inhalers, smoking, meals, and strenuous activity before testing; do not stop prescribed medicine unless the clinician tells you to. Wear comfortable clothing, seal your lips around the mouthpiece, and give a strong, sustained blow. Tell the tester if coughing, dizziness, or chest discomfort prevents you from completing a manoeuvre.

Use your prescribed asthma action plan for worsening symptoms. Seek emergency help if you are struggling to speak, breathing is rapidly worsening, your lips look blue or grey, you become drowsy or confused, or your reliever is not helping as directed. A low or changing FEV1 result should be discussed with your clinician, but urgent symptoms should not wait for lung-function testing.

Ask what your FEV1 result means alongside the other spirometry values, whether bronchodilator testing or repeat assessment is needed, and how your inhaler plan should change. Ask how to recognise an asthma flare and when nebuliser treatment or emergency care is appropriate.