What should you know about bellows spirometer?

The device uses a moving bellows or chamber that responds to your airflow. A sensor or scale turns that movement into measurements, such as the volume of air you can exhale and the force of the initial breath. These results help a clinician assess how open your airways are and how well your lungs move air.

During the test, you usually sit upright, breathe through a mouthpiece, and wear a nose clip so air does not escape through your nose. The clinician demonstrates a full breath in followed by a fast, strong, complete breath out. Several attempts may be needed because technique affects the reading. The test is not a diagnosis by itself; the result is interpreted alongside your symptoms, examination, medical history, and medicines.

Wear comfortable clothing that does not restrict your chest or abdomen. Follow the clinic’s instructions about meals, smoking, exercise, and inhalers before the appointment; do not stop a prescribed medicine unless the clinician specifically tells you to. Tell the team if you have recently had chest pain, an infection, surgery, or an episode of severe breathlessness.

Before each attempt, seal your lips around the mouthpiece. Fill your lungs as directed, then exhale with sustained effort until the clinician says to stop. You may feel briefly light-headed, tired, or cough during repeated efforts. Sit quietly and tell the operator if you feel unwell.

Contact a healthcare professional promptly for breathlessness that is new, worsening, or limiting ordinary activity. Seek urgent help for severe difficulty breathing, blue or grey lips, fainting, confusion, or chest pressure. During testing, stop and alert the clinician immediately if you develop chest pain, marked dizziness, or distress.

Ask which measurements were outside the expected range, whether your technique affected the result, and whether you need a repeat test or another assessment. You can also ask whether any inhaler should be used before testing and what symptoms should prompt a review.