Breathing and lung function tests

Oxygen assessment

What is it?

Your oxygen levels will be tested while you’re sitting down. Sometimes you’ll be asked to do a walking test to see if your oxygen levels go down as you exercise and, if that happens, whether extra oxygen means you can walk further. The outcome can help your health care professional decide if you should have oxygen therapy.

If your oxygen levels are low, your blood gases will be checked again while you are breathing in extra oxygen through your nose. The oxygen is delivered by small see-through tubes known as nasal cannula. This will help work out how much oxygen you need to improve the level of oxygen in your blood.

Chris Warbuton with cannula in garden
Chris using oxygen in his garden
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Last medically reviewed: January 2017. Due for review: January 2020

This information uses the best available medical evidence and was produced with the support of people living with lung conditions. Find out how we produce our information. If you’d like to see our references get in touch.