Hypoxemia occurs when your blood does not contain enough oxygen. The body cannot work well when it does not have enough oxygen, because every part of your body needs oxygen. Oxygen travels to all parts of the body through your blood. Hypoxemia can develop suddenly or can come on slowly.


Some common causes of hypoxemia include:

  • Long-term (chronic) lung diseases, such as chronic obstructive pulmonary disease (COPD) or interstitial lung disease. 

  • Disorders that affect breathing at night, such as sleep apnea.

  • Fluid buildup in your lungs (pulmonary edema). 

  • Lung infection (pneumonia).

  • Lung or throat cancer.

  • Abnormal blood flow that bypasses the lungs (shunt).

  • Certain diseases that affect nerves or muscles.

  • A collapsed lung (pneumothorax).

  • A blood clot in the lungs (pulmonary embolus).

  • Certain types of heart disease.

  • Slow or shallow breathing (hypoventilation). 

  • Certain medicines.

  • High altitudes.

  • Toxic chemicals and gases.


Not everyone who has hypoxemia will develop symptoms. If the hypoxemia developed quickly, you will likely have symptoms such as shortness of breath. If the hypoxemia came on slowly over months or years, you may not notice any symptoms. Symptoms can include:

  • Shortness of breath (dyspnea).

  • Bluish color of the skin, lips, or nail beds.

  • Breathing that is fast, noisy, or shallow.

  • A fast heartbeat.

  • Feeling tired or sleepy.

  • Being confused or feeling anxious.


To determine if you have hypoxemia, your health care provider may perform:

  • A physical exam.

  • Blood tests.

  • A pulse oximetry. A sensor will be put on your finger, toe, or earlobe to measure the percent of oxygen in your blood.


You will likely be treated with oxygen therapy. Depending on the cause of your hypoxemia, you may need oxygen for a short time (weeks or months), or you may need it indefinitely. Your health care provider may also recommend other therapies to treat the underlying cause of your hypoxemia.


  • Only take over-the-counter or prescription medicines as directed by your health care provider.

  • Follow oxygen safety measures if you are on oxygen therapy. These may include:

  • Always having a backup supply of oxygen.

  • Not allowing anyone to smoke around oxygen.

  • Handling the oxygen tanks carefully and as instructed.

  • If you smoke, quit. Stay away from people who smoke.

  • Follow up with your health care provider as directed.


  • You have any concerns about your oxygen therapy.

  • You still have trouble breathing.

  • You become short of breath when you exercise.

  • You are tired when you wake up.

  • You have a headache when you wake up.


  • Your breathing gets worse.

  • You have new shortness of breath with normal activity.

  • You have a bluish color of the skin, lips, or nail beds.

  • You have confusion or cloudy thinking.

  • You cough up dark mucus.

  • You have chest pain.

  • You have a fever.


  • Understand these instructions.

  • Will watch your condition.

  • Will get help right away if you are not doing well or get worse.