Blood oxygen level is the amount of oxygen circulating in the blood. Red blood cells carry most of the oxygen, collecting it from the lungs and delivering it to all parts of the body.
The body closely monitors blood oxygen levels to keep them within a specific range so that there is enough oxygen for the needs of every cell.
A person’s blood oxygen level indicates how well the body distributes oxygen from the lungs to the cells, and it can be important for people’s health.
A healthy blood oxygen level varies between 75 and 100 millimeters of mercury (mm Hg).
When arterial blood gas (ABG) test results reveal an oxygen level below 60 mm Hg, the medical community considers it low. In some cases, people with these results may require oxygen supplementation.
A blood oxygen level that is too low compared with the average level of a healthy person can be a sign of a condition known as hypoxemia. This develops when the body has difficulty delivering oxygen to all of its cells, tissues, and organs.
Oxygen saturation refers to the percentage of oxygen in a person’s blood. Medical professionals often use a device called a pulse oximeter for either a quick test or continuous monitoring. The device can attach to the person’s fingertip.
A healthy oxygen saturation level ranges between 95% and 100%. If a person’s levels drop below this range, they may experience symptoms associated with a lack of oxygen, such as trouble breathing and confusion.
An ABG test is a common way to monitor blood oxygen levels. This test involves taking a blood sample from an artery, usually in the wrist. This procedure is very accurate, but it can be a little painful.
Doctors carry out ABG tests in a hospital. However, people can test themselves at home using a small device known as a pulse oximeter. A person cannot perform an ABG test at home.
A pulse oximeter is a small clip that often attaches to a finger, although it will also work on an ear or a toe. It measures blood oxygen indirectly by light absorption through a person’s pulse.
Although the pulse oximeter test is easier, quicker, and less painful than the ABG test, it is not as accurate. Several factors can interfere with the results, including:
- dirty fingers
- bright lights
- darker skin tones
- nail polish
- poor circulation to the extremities
Learn how to choose the best pulse oximeter to purchase.
People should contact a doctor if they:
- experience severe and sudden shortness of breath
- experience shortness of breath when at rest
- have severe shortness of breath that worsens during exercise or physical activity
- wake suddenly with shortness of breath or a feeling of choking
- are at high altitude and experience severe shortness of breath with a cough, rapid heartbeat, and fluid retention
The treatment options for low blood oxygen levels include supplemental oxygen. Doctors can administer oxygen therapy in an office, or they can prescribe or recommend the use of home oxygen therapy (HOT).
A range of devices is available for delivering and monitoring HOT, but some require a prescription.
People can make lifestyle adjustments to reduce the symptoms of low oxygen levels, as well as improve their general health and quality of life. Changes that will likely be beneficial include:
- quitting smoking
- avoiding secondhand smoke
- eating a nutritious diet containing plenty of fruits, whole grains, lean protein, and vegetables
- exercising regularly
Learn more about following a well-balanced diet.
Many conditions can cause low blood oxygen levels. Treating the underlying condition responsible will generally improve blood oxygen levels.
People living with chronic lung diseases, such as COPD, and those who catch COVID-19 may need regular blood oxygen monitoring.
People with low blood oxygen can also make lifestyle changes, such as adjusting their dietary and exercise habits. In conjunction with oxygen therapy, these changes could help a person raise their oxygen saturation levels.
A person’s blood oxygen level refers to the amount of oxygen circulating in their blood. A person can measure blood oxygen levels using a pulse oximeter. On a pulse oximeter, doctors consider levels under 95% to be low.
Several conditions can cause low blood oxygen levels, including asthma, anemia, and COVID-19.
The treatment will often involve addressing the underlying cause, but doctors may sometimes also recommend oxygen therapy or lifestyle modifications.
Read the article in Spanish.
by Editorial Staff | October 21, 2020
Let’s get a few things straight about pulse oximetry, which seems to be in the news a lot these days. Because knowing only a little bit about pulse oximetry can be misleading. A pulse oximeter measures the level of oxygen saturation in your red blood cells. This handy tool, which is usually clipped to the end of your finger or earlobe, has gained attention during the COVID-19 pandemic as a potential tool to identify hypoxia (low blood oxygen saturation) which is one troubling sign of severe illness caused by COVID-19. So, should everyone make sure they have a pulse oximeter in their medicine cabinet? Not necessarily.
The Food and Drug Administration (FDA) considers pulse oximeters to be prescription medical devices, yet most pulse oximeters that are found on the internet or in drug stores are specifically labeled “not for medical use” and have not been reviewed by the FDA for accuracy. And when we’re talking about the purpose behind purchasing a pulse oximeter during, and specifically for, the pandemic—accuracy matters. Yet we’ve seen an upcropping of opportunistic manufacturers selling pulse oximeters as a medicine cabinet staple.
We saw something similar happen with hand sanitizer when the pandemic first began. While the Centers for Disease Control and Prevention (CDC) is clear that washing your hands with soapy water is best, they suggest using hand sanitizer as a reliable option when a sink isn’t readily available. As a result, huge amounts of hand sanitizer were sold and nearly every store became out of stock. Seeing the need, many companies began manufacturing and selling hand sanitizer quickly. And it soon became apparent that not all products are created equally, resulting in the FDA coming down hard on poorly made sanitizer solutions. There is now a list of hand sanitizers that consumers are recommended to avoid—either because they are ineffective or even potentially cause harm.
Taking a step back, pulse oximeters have been around for 50 years and they are a valuable tool available to patients and providers when collaboratively tracking oxygenation of the blood while treating some chronic lung and heart diseases. They are typically introduced during a medical setting as one tool to use to report back on overall disease management. During the pandemic, they might even be recommended, under the guidance of your healthcare provider, to self-monitor COVID-19 related symptoms.
So, what’s the best way to monitor symptoms? The CDC has developed a helpful coronavirus symptom checker that covers nine life-threatening symptoms of disease to watch for including chest pain, severe shortness of breath and disorientation. These approaches to assessing how a person feels and acts, and then providing guidance on next steps such as seeking emergency care, calling your healthcare provider or continuing to monitor symptoms help guide individuals through a collaborative treatment process.
And remember, we don’t yet have a vaccine nor a targeted treatment for COVID-19. The best course of action you can take to protect the health of yourself, your family and your community is to prevent the spread of the disease by washing your hands, wearing a mask, social distancing and staying home as much as you are able - especially if you are feeling unwell or were around someone who had COVID-19.
Our takeaway message? A pulse oximeter may be a recommended tool to use under the guidance of your healthcare provider to monitor symptoms, but it should not be relied upon without medical oversight, nor without paying heed to other signs and symptoms of illness.
Disclaimer: The information in this article was medically reviewed and accurate at the time of posting. Because knowledge and understanding of COVID-19 is constantly evolving, data or insights may have changed. The most recent posts are listed on the EACH Breath blog landing page. You may also visit our COVID-19 section for updated disease information and contact our Lung HelpLine at 1-800-LUNGUSA for COVID-19 questions.
Blog last updated: October 25, 2021