How to use a spirometer

A spirometer measures how much air you can breathe out and how quickly you can move it. The device may be used during spirometry to investigate cough, wheeze, breathlessness, or suspected airway disease. Some home devices are incentive spirometers, which encourage slow deep breaths after illness or surgery. These devices have different goals, so confirm which type you have and what each marker means.

Follow the instructions from your clinician because technique affects the reading. Sit upright with both feet supported and loosen tight clothing. Keep the device level if advised, place the mouthpiece fully between your lips, and avoid blocking it with your tongue. Take the breath in or out exactly as instructed, then reset and repeat only as directed. Do not force repeated attempts if you feel dizzy; pause, breathe normally, and tell the tester. Avoid eating heavily, smoking, or strenuous activity before a clinic test when your appointment instructions advise this.

Stop and seek urgent help if using the device causes severe breathlessness, chest pain, fainting, blue lips, or confusion. A low home reading is not a diagnosis by itself, and a normal reading does not rule out every breathing problem. Contact your clinician if readings are repeatedly below your personal plan, symptoms are changing, or you cannot perform the manoeuvre without distress.

Ask which type of spirometer you are using, whether your medicines should be taken before testing, how many attempts to record, and which result or symptom should trigger a call. Ask for a demonstration and a written action plan if you are monitoring breathing at home.