What Is Oxygen Therapy?

Oxygen therapy is a treatment that provides you with extra oxygen, a gas that your body needs to work properly.

Normally, your lungs absorb oxygen from the air. However, some diseases and conditions can prevent you from getting enough oxygen. Oxygen therapy can help ensure that you get enough oxygen, which may help you function better and be more active.

Oxygen is supplied in a metal cylinder or other container. It flows through a tube and is delivered to your lungs in one of the following ways:

  • Through a nasal cannula, which consists of two small plastic tubes, or prongs, that are placed in both nostrils.
  • Through a face mask, which fits over your nose and mouth.
  • Through a tracheostomy. This is a surgically made hole that goes through the front of your neck and into your windpipe. A breathing tube is placed in the hole to help you breathe. Oxygen delivered this way is called transtracheal oxygen therapy.

Oxygen therapy can be done in a hospital, another medical setting, or at home. If you need oxygen therapy for a chronic (ongoing) disease or condition, you may receive home oxygen therapy.


To understand how oxygen therapy works, it helps to understand how your respiratory system works. This system is a group of organs and tissues that help you breathe. It includes the airways and lungs.

The airways are pipes that carry oxygen-rich air to your lungs. They also carry carbon dioxide, a waste gas, out of your lungs.

Air enters your body through your nose or mouth, which moistens and warms the air. The air then travels through your voice box and down your windpipe. The windpipe divides into two tubes called bronchi that enter your lungs.

Within your lungs, your bronchi branch into thousands of smaller, thinner tubes called bronchioles . These tubes end in bunches of tiny round air sacs called alveoli.

Each of these air sacs is covered in a mesh of tiny blood vessels called capillaries. The capillaries connect to a network of arteries and veins that move blood through your body.

Oxygen from the air moves through the very thin walls of the alveoli to the surrounding capillaries. The oxygen-rich blood then travels to the heart through the pulmonary vein and its branches. The heart pumps the oxygen-rich blood to your organs. (For more information, go to the Diseases and Conditions Index How the Lungs Work article.)

Certain acute (short-term) and chronic (ongoing) diseases and conditions can affect the transfer of oxygen from the alveoli into the blood. Examples include pneumonia  and COPD (chronic obstructive pulmonary disease).

Your doctor will decide whether you need oxygen therapy based on the results of tests, such as an arterial blood gas test and a pulse oximetry test. These tests measure how much oxygen is in your blood. A low level of oxygen is a sign that you need oxygen therapy.

Because oxygen is considered a medicine, your doctor must prescribe it.


For many people who get oxygen therapy, the supplemental (extra) oxygen allows them to function better and be more active. Oxygen therapy can help in various ways. It may help:

  • Decrease shortness of breath and fatigue (tiredness)
  • Improve sleep in some people who have sleep-related breathing disorders
  • Increase the lifespan of some people who have COPD

Although you may need oxygen long term, the therapy doesn’t have to limit your daily routine. Portable oxygen units can make it easier for you to move around and do many daily activities. Talk with your doctor if you have questions about whether certain activities are safe for you.

A home equipment provider will work with you to make sure you have the supplies and equipment you need. Trained personnel also will show you how to use the equipment correctly and safely.

Oxygen therapy generally is safe, but the oxygen can pose a fire hazard. To use your oxygen safely, follow the instructions you receive from your home equipment provider.

Source: National Heart, Lung and Blood Institute