Spirometry: what your lung function and lung age mean

Spirometry is a simple breathing test that measures how much air you can breathe out, and how quickly. It’s one of the six tests in our Health Autonomy assessment in Chudleigh, together with a quick reading of your blood oxygen.

What happens

You take a deep breath in and blow out as hard and fast as you can into a mouthpiece. We repeat it a few times for accuracy. We also clip a small sensor on your finger to read your blood oxygen.

What it measures

• FVC: the total amount of air you can breathe out.
• FEV1: how much you can breathe out in the first second.
• Lung age: how your lung function compares with the average for your age.
• SpO₂: blood oxygen saturation, showing how well your lungs and circulation deliver oxygen to your body.

Why it matters

Lung function naturally declines with age, and is closely linked to long-term health and how easily you cope with everyday exertion. For athletes, it shows whether breathing could be limiting your endurance. Your results also feed into your calculated VO₂ max, one of the strongest predictors of long-term health.

Like every test in the assessment, it’s a baseline, not a diagnosis. If anything needs additional checking, we’ll advise you of the next step.

Before your test

• Avoid smoking for at least an hour, and a heavy meal for 2 hours.
• Let us know if you’ve recently had chest, abdominal or eye surgery, or a recent heart problem.

If you’re short of breath at rest, have chest pain or are coughing up blood, don’t wait for an assessment: contact your GP or NHS 111, or call 999 in an emergency.

Read about the 12-lead ECG · See all six tests