What Happens When Your Oxygen Level Drops Too Low?

What Happens When Your Oxygen Level Drops Too Low?

Breathe in. Breathe out. Along with the back beat provided by the heart, breathing is the rhythm of life. Essential to that life is oxygen. This life-supporting element comprises 20% of Earth’s atmosphere, and comprises 65% of your body. When your body does not have enough oxygen, serious health consequences occur.


Each time you breathe in, you are taking oxygen into your lungs. From your lungs, oxygen attaches to your red blood cells. Through your circulatory system, your blood then delivers oxygen to every living cell in your body. Your cells use oxygen molecules to make energy and to stay alive. Without oxygen, the cells die and your organs stop functioning.


What is hypoxemia?

Having just the right amount of oxygen in your blood is important. Too little oxygen and too much oxygen are both harmful to your health. Therefore, your body controls and regulates the amount of oxygen in your blood at all times. When your body is unable to do this, and the level of oxygen in your blood drops too low, the condition is called hypoxemia.


Hypoxemia can deprive your body of much needed oxygen. When your body’s tissues and organs don’t have enough oxygen to function properly, the condition is called hypoxia. Hypoxia is a direct result of hypoxemia, and it is a life threatening condition.


How do you measure blood oxygen level?

There are two common tests used by doctors to measure the oxygen level in your blood.


Arterial blood gas (ABG) test

An ABG is the best way to measure your blood oxygen level. To perform this test, your doctor will use a needle to draw blood from one of your arteries. An ABG blood draw procedure is different than a blood draw used for most blood tests. A normal blood test does not require oxygenated blood, so doctors will draw blood from one of your veins close to the skin that is easy to access. Usually, normal blood draws take blood from veins in your arm. An ABG requires oxygenated blood, so doctors will draw blood from one of your arteries. Arteries are located a little deeper in your body than veins, so they are not as easy to access. Most commonly, blood draws for an ABG test take blood from an artery in your wrist.  


Because your arteries are deeper than your veins, drawing blood for an ABG test can cause discomfort. However, an ABG test is the most accurate way to measure the amount of oxygen in your blood. It can also reveal levels of other gases in your blood, as well as measure your blood’s pH (acid/base level).


Pulse oximeter test

A pulse oximeter test is the most common way used to measure blood oxygen level. This is a non-invasive test, meaning that no needle or instrument enters your body. For this test, your doctor will use an instrument called a pulse oximeter. Your doctor will clip a small device onto the outside of your body, usually on your finger, toe or ear lobe. The device is connected to a pulse oximeter, and uses ultraviolet light to measure the oxygen in your capillaries. Capillaries are webs of small blood vessels that connect your arteries and veins.

Using the pulse oximeter is an easy, painless procedure, and it provides test results quickly. When you need to monitor your blood oxygen level and measure it often, a pulse oximeter offers a good option. Pulse oximeters are so easy to use that some people purchase their own and measure their blood oxygen levels themselves at home.


However, a pulse oximeter is not as accurate as an ABG test. Wearing nail polish, external light in the room, temperature and other variables can all affect the test results. Also, if you smoke, the presence of other gases in your blood can greatly reduce the accuracy of pulse oximeter test results.


Other less common tests are also available. These tests require you to breathe into a tube. The tube is connected to an instrument that uses a computer to measure the oxygen saturation of your blood. When measuring your blood oxygen level, your doctor may also find it helpful to perform a physical examination and listen to your heart and lungs.


What are normal blood oxygen levels?

When using an ABG test to measure the amount of oxygen in your blood, the range for a normal result is 75 – 100 millimeters of mercury (mmHg). On your lab report, your ABG test results may be listed as:



This is your partial pressure of oxygen, and it measures the pressure of oxygen dissolved in your blood and how well oxygen is able to move from your lungs into the blood. This is the result that, when normal, falls between 75 – 100 mmHg.


This is your partial pressure of carbon dioxide, and it measures the pressure of carbon dioxide dissolved in your blood and how well carbon dioxide is able to move out of your body.

O2 Sat

This is your oxygen saturation, and it measures how much of the hemoglobin in your red blood cells is carrying oxygen.


The pH value measures the acid/base balance of your blood.


This is your bicarbonate, and it measures the amount of a chemical in your blood that keeps the pH of your blood from becoming too acidic or too basic.

When using a pulse oximeter to measure the oxygen saturation of your blood, the range for a normal result is 95% – 100%. The result from a pulse oximeter is called an O2 sat.


What are low blood oxygen levels?

A PaO2 reading from an ABG test that is below 75 mmHg, and an O2 sat reading from a pulse oximeter test that is below 95% both indicate a low oxygen level in your blood. If you have test results at or below these readings, you have hypoxemia.


With some diseases, your normal range may be different. For example, if you have a chronic obstructive pulmonary disease (COPD) like emphysema, chronic bronchitis or refractory (non-reversible) asthma, your normal oxygen levels may be lower than if you had healthier lungs.


What happens when your oxygen level drops to 60?

An ABG test with a PaO2 reading of 60 mmHg or below indicates an extremely low oxygen level. If your blood oxygen level is that low, you will probably need supplemental oxygen therapy. Supplemental oxygen therapy is a treatment that delivers oxygen gas for you to breathe.


Typically, you will receive supplemental oxygen through a device called a cannula (tube) that is clipped to the outside of your nose, or you will receive it through a breathing mask. Sometimes, the oxygen is delivered directly through a tube into your trachea (windpipe). The manner and amount of time you receive supplemental oxygen therapy depends upon your unique needs. You may receive supplemental oxygen at home, through a portable machine when you travel or require hospitalization to receive it.


What are the symptoms of low blood oxygen levels?

When your blood oxygen levels drop too low, you can experience symptoms. Specific symptoms can vary between individuals. The number and severity of symptoms will depend upon the severity of your hypoxemia and its underlying causes. Symptoms can include:

  1. Headache

  2. Shortness of breath while resting

  3. Severe shortness of breath after physical activity

  4. Rapid breathing

  5. Wheezing

  6. Coughing

  7. Choking sensation

  8. Change in heartbeat

  9. Chest pain

  10. Sweating

  11. Confusion

  12. Dizziness

  13. Lack of coordination

Left untreated, cyanosis can develop. Cyanosis can cause your skin and membranes to turn a blue color. The bluish tint usually appears on your hands, feet, lips and under your fingernails. Cyanosis indicates that your blood oxygen level is severely low. When it gets that low, it is life threatening and you should seek medical attention immediately.


What causes low blood oxygen levels?

There are several types of environmental and medical conditions that can cause hypoxemia.

Environmental conditions

If the air you are breathing has a reduced amount of oxygen in it, it can limit your body’s ability to supply itself with enough oxygen. The most common environmental condition that can cause hypoxemia is high altitude. At high altitudes, the amount of oxygen in the atmosphere is much less than at sea level.


Breathing too slowly or too shallowly is called hypoventilation. Conditions that can cause hypoventilation that leads to hypoxemia include:

  1. Guillain-Barre syndrome

  2. Amyotrophic lateral sclerosis‎ (ALS or Lou Gehrig’s disease)

  3. Spinal injury

  4. Brain injury

  5. Collapsed lung

  6. Sleep apnea (interrupted breathing during sleep)

  7. Drug or alcohol poisoning

Lung diseases

Some diseases reduce your lungs’ ability to take in oxygen from the air and transfer it to your blood properly. These diseases include:

  1. Chronic obstructive pulmonary disease (COPD) like:

  2. Emphysema

  3. Chronic bronchitis

  4. Refractory (non-reversible) asthma

  5. Pneumonia

  6. Cystic fibrosis

  7. Acute respiratory distress syndrome (ARDS)

  8. Pulmonary edema (fluid in the lungs)

Circulatory disorders

Even if the lungs are working properly, the circulatory system must be functioning in order to get oxygen to all parts of your body. Circulatory disorders that can cause hypoxemia include:

  1. Heart failure

  2. Heart and blood vessel deformations

  3. Pulmonary embolism (blood clot in the lung)


It is your red blood cells that carry oxygen throughout your body via the blood stream. So, anemia (a reduced number of red blood cells in your blood) will naturally reduce the amount of oxygen in your blood. Causes of anemia include:

  1. Iron deficiency

  2. Vitamin B12 deficiency

  3. Folate deficiency

  4. Chronic liver disease

  5. Chronic kidney disease

  6. Inherited blood diseases like sickle cell and thalassemia

  7. Leukemia and other cancers


When to see a doctor

Low blood oxygen levels can lead to serious health consequences. You should see your doctor as soon as possible after noticing one of the following symptoms:

  1. Shortness of breath after slight exertion or when you’re at rest

  2. Shortness of breath that gets worse when you exercise or are physically active

  3. Abrupt awakenings with shortness of breath or a feeling that you’re choking (these may be symptoms of sleep apnea)

You should seek immediate medical attention after noticing signs of cyanosis (when your hands, feet, lips or fingernails turn a blue color).


How do you treat low blood oxygen levels?

Treatments for hypoxemia aim to increase the oxygen saturation of your blood. Treatments include medications and therapies that are intended to address the underlying causes of the low oxygen levels in your blood. In a more severe case, your doctor may also prescribe supplemental oxygen therapy.

These self-care suggestions can also help with hypoxemia:

  1. If you smoke, quit.

  2. Avoid second-hand smoke.

  3. Eat a healthy diet including plenty of fruits and vegetables.

  4. Drink plenty of water.

  5. Exercise 30 minutes per day for at least 5 days of the week.

  6. Practice deep breathing exercises daily.

Hypoxemia symptoms can go away with treatment. Depending on the cause, you may require treatment once or on an ongoing basis. Your doctor will work with you to manage the condition so you can live an active, healthy life. Untreated hypoxemia can lead to hypoxia (low oxygen levels in your body’s tissues and organs). If you are diagnosed with hypoxia, hospitalization is often required for treatment.


Monitoring and managing hypoxemia.

Low oxygen levels in your blood can occur from time to time as the result of temporary physical or environmental conditions. When this happens, it is generally not harmful to your health. Your blood oxygen levels will usually go back to normal in short amount of time, and no monitoring or management is required.


However, if a chronic condition is the underlying cause of your hypoxemia, you will likely require regular, on-going blood oxygen monitoring. In this case it is critically important that you manage your chronic condition well.

How can Centric Healthcare help?

When your blood oxygen levels drop too low, Centric Healthcare offers services that can help.


Private Duty Nursing Services

One example of the services Centric Healthcare offers is private duty nurses who attend to your medical needs in your home. Examples of our services that can assist in the treatment of hypoxemia include: providing respiratory treatments, administering treatments and medications to treat the causes of hypoxemia, and helping you with blood oxygen saturation measurements using a pulse oximeter.

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