Lung volumes testing (also known as body plethysmography) is a gentle, non-invasive test that provides a deeper look at how much air your lungs can hold and how efficiently they empty with each breath. By measuring both the air you inhale and the air that may remain trapped after exhaling, this test helps identify subtle changes in lung capacity that may not appear on basic breathing tests.
These insights give your care team a clear understanding of how your lungs are functioning, helping guide treatment decisions that support easier breathing, improved comfort, and better day-to-day activity.
Why it's Ordered
Spirometry measures how quickly air moves out of your lungs — but lung volumes measure something different: how much air is in your lungs, and how your lungs are functioning overall. Lung volume testing can help your doctor:
• Identify air trapping, which can occur in COPD
• Detect restriction, where the lungs may not fully expand
• Better understand symptoms such as shortness of breath
• Provide a fuller picture when spirometry results don’t explain symptoms
• Support diagnosis and guide treatment decisions
Lung volumes are done alongside spirometry and DLco to give the most complete assessment.
What to Expect
Lung volume testing is done while you are seated and comfortable. During the test:
• You will sit inside a body box, which is made of clear glass all around.
• The door closes and is held gently in place with magnets, and it can be released easily from the inside at any time — you are always in control.
• You will breathe through a mouthpiece while following simple instructions from our staff.
• At certain points, a small shutter creates gentle resistance, and you’ll be asked to take short, quick breaths (similar to panting).
• Some steps may be repeated to make sure the results are accurate and consistent.
Our team will guide you through each step, and you can pause at any time if you need a break.
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How to Prepare
To help your appointment run smoothly:
- Bring your Alberta Health Care card
- Wear loose, comfortable clothing
- Bring a list of your current medications (inhalers, tablets, injections, etc.)
- You may be asked to hold certain breathing medications (inhalers) before testing
(only if instructed — please follow the directions provided by your doctor or our clinic
If you are unsure about medication instructions, please contact our clinic prior to your appointment. Our team will guide you through each step and ensure you feel comfortable and supported throughout your visit.
FAQ
Yes. Lung volume testing is very safe. It does not involve needles, sedation, or any invasive procedures. You are closely supervised by trained staff the entire time.
No. The body box is made of clear glass all around, and the door is held closed with magnets. It can be released easily from the inside at any time. You are always in control, and our staff are right there with you throughout the test.
Most of the test feels like normal breathing. At certain points, you’ll be asked to take short, quick breaths (like panting) while gently breathing against a small amount of resistance. Many patients say it feels unusual at first, but it’s very manageable.
Lung volume testing is usually completed as part of your full lung function appointment. The lung volume portion often takes about 10–15 minutes, depending on how many measurements are needed.
Those short, quick breaths help the machine measure how much air is in your lungs and how your lungs are functioning. It’s a normal part of the test and helps ensure accurate results.
That’s completely understandable — and very common. The body box is clear glass all around, you are seated the entire time, and you can stop at any moment. Our staff will explain each step slowly and support you through the process.
Your results are reviewed as part of your overall assessment. A report is then sent to your referring doctor, who will discuss the results and next steps with you.
Your results are reviewed and interpreted as part of your overall lung function assessment. A report is then sent to your referring doctor, who will discuss the results and next steps with you.