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How does COVID-19 lower a person’s oxygen levels?

Many people with COVID-19 have low levels of oxygen in their blood, even when they feel well. Low oxygen levels can be an early warning sign that medical care is needed.

Low blood oxygen, known as hypoxemia, means that the level of oxygen in the blood has dropped below average, normal levels, due to one or more of many different causes. Under most circumstances, breathing room air, normal readings range from 95 to 100 percent. Levels above 90 percent are not considered low, so you probably are worrying. A problem with any of these factors — for example, high altitude, asthma or heart disease — might result in hypoxemia, particularly under more extreme conditions, such as exercise or illness. When your blood oxygen falls below a certain level, you might experience shortness of.

What is a pulse oximeter?

A pulse oximeter measures how much oxygen is in someone’s blood. It is a small device that clips onto a finger, or another part of the body. They are used often in hospitals and clinics and can be bought to use at home.

Many people consider oxygen level an important sign of how well a body is working, just like a person’s blood pressure or body temperature. People who have a lung or heart condition may use a pulse oximeter at home to check how they are doing, as directed by their health care provider. People can buy pulse oximeters without a prescription at some pharmacies and stores.

Can a pulse oximeter tell if someone has COVID-19 or how well they are doing if they have it?

We do not recommend using a pulse oximeter as a way to tell if someone has COVID-19. Get tested if you have signs of COVID-19 or if you have been close to someone who has it.

If someone has COVID-19, a pulse oximeter may help them keep watch over their health and to know if they need medical care. However, while a pulse oximeter may help someone feel like they have some control over their health, it does not tell the whole story. Oxygen level measured by a pulse oximeter is not the only way to know how sick someone is. Some people may feel very sick and have good oxygen levels, and some may feel OK, but have poor oxygen levels.

Pulse oximetry results may not be as accurate for people with darker skin. Their oxygen levels are sometimes reported as higher than they really are. People who check their own oxygen levels, or those who check it for them, should keep this in mind when looking at results.

Oxygen levels may be low if someone feels short of breath, is breathing faster than usual, or feels too sick to do their usual daily activities, even if a pulse oximeter says their oxygen levels are normal. Call a doctor or another health care provider right away if you have these symptoms.

What are normal readings?

A normal level of oxygen is usually 95% or higher. Some people with chronic lung disease or sleep apnea can have normal levels around 90%. The “SpO2” reading on a pulse oximeter shows the percentage of oxygen in someone’s blood.

If your home SpO2 reading is lower than 95%, call your health care provider.

Disclaimer

If you have any medical questions or concerns, please talk to your healthcare provider. The articles on Health Guide are underpinned by peer-reviewed research and information drawn from medical societies and governmental agencies. However, they are not a substitute for professional medical advice, diagnosis, or treatment.

A normal blood oxygen level depends on what exactly you’re measuring. The partial pressure of oxygen in a sample of arterial blood (PaO2) is normally 75–100 mm Hg. The partial pressure of oxygen in a sample of venous blood (PvO2) varies but is lower than this. The arterial oxygen saturation (SaO2), which can be measured by wearing a pulse oximeter, is normally >95%

One of the primary functions of the blood is to carry oxygen around the body, delivering it to the tissues. The arteries carry blood away from the heart and contain more oxygen; the veins carry blood back to the heart and contain less oxygen. Having a low blood oxygen level means less oxygen is available for use by the body’s cells, which hinders cellular energy production. This can cause shortness of breath, headache, confusion, and—if oxygen levels are very low—organ damage and death. Low blood oxygen levels typically result from lung disease.
Low blood oxygen levels are addressed by treating the underlying problem. If this isn’t possible, supplemental oxygen (breathing oxygen through a tube) may be necessary. In some circumstances, such as in individuals with chronic obstructive pulmonary disease (COPD), it may be more appropriate to keep the SaO2 between 88–92%.

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What Is Normal Body Oxygen Level

Normal Oxygen Saturation Levels In Adults

In medicine, using the term “normal” can sometimes be off-putting. Saying something is “normal” implies that everything else is “abnormal.” Additionally, saying something is “normal” may not be accurate, since something that is “normal” for you may not be “normal” for somebody else. Therefore, instead of saying certain values are “normal,” alternative terminology may be to say that these values are “healthy” or “within the reference range.”
Additionally, some values have well-defined cutoffs, while others do not. For example, when looking at hemoglobin A1c levels, a value of 6.5 or greater is always diagnostic of diabetes. On the other hand, when looking at testosterone levels, some use cutoffs of 270–1,070 ng/dL while others use cutoffs of 300–1,000 ng/dL.
The information below represents values that are commonly used as cutoffs. However, depending on the specific source you’re looking at or the laboratory you go to, their values may be a little different.