Oxygen therapy

Why is oxygen therapy used?

If you’re living with a lung condition you may be offered oxygen therapy if your blood oxygen levels are low. If they are, breathing in air with a higher concentration of oxygen can correct this. 

Oxygen is a gas that is vital to all the cells in your body. At sea level, the air we breathe in contains about 21% oxygen. Our bodies need oxygen for all their active processes  like digesting food, contracting muscles or even just thinking.

If you have low blood oxygen levels, oxygen therapy can help make it easier to do things you might otherwise find difficult. For example, it can enable you to walk further. It can also improve your life expectancy.


If you are already on oxygen and have never been assessed, ask your GP to refer you to a specialist. The specialist will assess why you are breathless and check if you have low oxygen levels.

What is oxygen therapy?

There are several different kinds of oxygen therapy:

  • long term oxygen therapy (LTOT) - used to stabilise oxygen levels for 15 hours and more a day
  • nocturnal oxygen therapy (NOT) - used to improve oxygen levels when you’re asleep
  • ambulatory oxygen therapy (AOT) - used to improve oxygen levels when you’re active
  • palliative oxygen therapy (POT) - used to manage severe breathlessness that doesn’t respond to other treatments

Next: How does oxygen therapy help? >

We use your comments to improve our information. We cannot reply to comments left on this form. If you have health concerns or need clinical advice, call our helpline on 03000 030 555 between 9am and 5pm on a weekday or email them.

Download our oxygen therapy PDF (263KB)

Last medically reviewed: February 2018. Due for review: February 2021

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.