Oxygen is essential to life—just three to six minutes without oxygen can cause brain damage or even death. Your blood oxygen level, or the amount of oxygen circulating in the blood, can be an indicator of your overall wellness. You can even measure your blood oxygen level at home with a device called a pulse oximeter. The device is placed on a finger (a toe or earlobe may also be used) and uses a light to measure your oxygen saturation.
Is it necessary to keep track of your blood oxygen? While a healthy person doesn’t need to monitor their blood oxygen level regularly, it may be a good idea for some people. A good example is that some people who had COVID-19 were instructed by their physicians to monitor their oxygen saturations at home to make sure they weren’t getting worse. Some heart or lung conditions, respiratory illnesses, and environmental factors can contribute to lower-than-normal blood oxygen levels. When blood oxygen drops too low, serious health effects can occur. Luckily, there are ways to increase your blood oxygen levels, such as getting exercise, breathing deeply, or moving into an upright position. Keep reading to learn the causes of low blood oxygen, how it’s measured, and ways to increase it naturally.
What does a blood oxygen level mean?
After you inhale oxygen (O2) through your nose or mouth, it travels through the lungs into the bloodstream. From there, it is distributed to your body’s cells, where it is used to metabolize glucose and create energy. The byproduct of this process is waste gas, or carbon dioxide (CO2), which is removed from the bloodstream and exhaled by the lungs.
Your blood oxygen level, or blood oxygen saturation, indicates how much oxygen is circulating in your blood. Blood oxygen is measured as a percent saturation of hemoglobin (the red protein that carries oxygen) ranging from zero to 100%, says Bruce Spiess, MD, a cardiothoracic anesthesiologist, expert on blood management, and Medical Director of Durham-based Hemosonics. Blood oxygen is measured in two ways:
- Pulse oximetry: This is a noninvasive test using a small device with a red light. It’s clipped onto a finger, toe, or earlobe and measures your heart rate and blood oxygen saturation level (SpO2 or O2Sat), the percentage of hemoglobin that’s full of oxygen. The margin of error for pulse oximeters is about 2%.
- Arterial blood gas testing: Sometimes, an arterial blood gas (ABG) is necessary to get more information about the levels of oxygen and carbon dioxide in the blood. Getting blood from an artery rather than a vein provides the most accurate measures of these substances and also provides information about the acid-base balance in the bloodstream. To perform an ABG, blood is usually withdrawn from an artery in the wrist. The arm or groin may also be used. Results obtained from an ABG include:
- Oxygen saturation (SpO2 or O2Sat) measures the percent of red blood cells carrying oxygen. In other words, it indicates how much of the oxygen you breathe in makes it to the tissues of the body.
- Partial pressure of oxygen (PaO2) measures the oxygen dissolved in the blood. It shows how efficiently oxygen travels from the lungs to the bloodstream.
- Partial pressure of carbon dioxide (PaCO2) is the amount of carbon dioxide in the blood. It shows how efficiently carbon dioxide leaves the body.
- Acid-base balance (pH level) measures blood acidity. Too much acid (acidosis) or too much base (alkalosis) are symptoms of medical conditions that upset the body’s acid-base balance.
- Bicarbonate level is calculated from the pH and PaCO2 to show how much base is in the bloodstream. Measuring bicarbonate indicates how well the body’s metabolism is working.
According to research, ABG is considered the gold standard for measuring blood oxygen levels. For individuals with a reading of less than 90%, pulse oximetry may not be adequate for determining blood oxygenation; in that case, ABG is preferred. What’s more, ABG testing can be used as a diagnostic tool for serious kidney and respiratory conditions, while pulse oximetry cannot.
Reasons for testing your blood oxygen level
Your healthcare provider may check your blood oxygen level to ensure your tissues are getting enough oxygen in the following situations:
- You’re receiving oxygen therapy in the hospital.
- You’re experiencing acute symptoms that may be signs of a pH imbalance, including but not limited to:
- Rapid or deep breathing
- Nausea and vomiting
- Arrhythmia (abnormal heartbeat)
- Confusion
- Fatigue
- Muscle cramps or twitching
- Signs of low oxygen, such as blue fingers, toes, or lips
- You are receiving treatment for a lung disease or health condition that increases your risk of low blood oxygen levels, such as:
- Asthma
- Chronic obstructive pulmonary disease (COPD)
- Cystic fibrosis
- Emphysema
- Heart disease
- Myasthenia gravis (an autoimmune condition causing muscle weakness)
- COVID-19 (coronavirus)
- Pneumonia
- You’re experiencing symptoms after one of the following:
- Carbon monoxide poisoning
- An inhalation injury from smoke, hot air, or chemicals
- A head or neck injury
What should your blood oxygen level be?
An oxygen saturation level (SpO2) from 95% to 100% is normal, says Dr. Spiess. However, individuals with a chronic lung disease like pneumonia or COPD, or those who live at higher elevations, may have a slightly lower SpO2 level. In that case, your provider will let you know whether your reading is within a healthy range. It is important to know that for people with COPD, high oxygen levels can also be dangerous. Your healthcare provider will tell you what is a safe range of oxygen saturation for your particular situation.
Here’s how to decipher a pulse oximeter reading:
- Normal: 95% to 100% is considered a normal blood oxygen level
- Sometimes normal: 90% to 95% can be normal in individuals with respiratory diseases such as COPD, but individuals without these health conditions should seek medical attention.
- Low: A value of less than 90% indicates low oxygen saturation, which requires emergency medical attention. Treatment typically involves increasing your oxygen levels with oxygen therapy (supplemental oxygen).
Dr. Speiss says that while levels between 90% and 95% don’t always signify the need for intervention, a quick drop below 95% is concerning. A reading less than 90% can be dangerous, and anything less than 70% is life-threatening.
What if your reading is 92%? Dr. Spiess says it depends. For example, if your prior reading was 85% and your medical care team performed an intervention, 92% might be considered good or improving. On the other hand, a person with a previous level of 95% that drops to 92% is alarming, he says.
7 ways to increase blood oxygen levels
If you’re wondering how to increase your level of oxygen, here are seven methods to try.
1. Get moving
Regular cardiovascular exercise like walking, cycling, or swimming is one of the most effective ways to increase oxygen levels, says Paul Daidone, MD, a double board-certified internal medicine and addiction medicine physician with True Self Recovery in Rogers, Arkansas. “It helps your lungs and heart work better and increases your body’s ability to take in and use oxygen,” he says.
2. Practice breathing techniques
“Deep breathing exercises can help increase your oxygen levels by helping you to breathe more deeply and efficiently,” says Dr Daidone. You can try pursed lip breathing—breathing in for two counts and out for four with your lips pursed together, or diaphragmatic breathing (belly breathing)—breathing deeply toward the belly, then breathing out through pursed lips.
Blowing up a balloon is also an excellent exercise to help open the alveoli (tiny air sacs where gas exchange between air and the blood takes place) and increase lung capacity.
3. Sit in an upright position
Sitting upright will help improve blood oxygen levels quickly by expanding the lungs, says Dr. Spiess. One small study found that SpO2 levels in healthy individuals were higher when they were in an upright, seated position than when they were supine (lying horizontally with the face up), prone (lying horizontally with the face down), or lying on their right or left side. Research suggests that individuals at risk for hypoxemia (low oxygen levels in the bloodstream) may benefit from sleeping in a semi-upright position.
4. Try coughing
Coughing helps loosen trapped mucus, move it from the airways, and open up the alveoli, says Dr. Spiess. Try “controlled coughing” by inhaling and coughing deeply with a partially open mouth. If this is difficult, try taking a medium breath and making a “ha” sound to force air out quickly three to four times and then coughing.
5. Eat iron-rich foods
Foods rich in iron, such as spinach, lentils, and red meat, can help increase oxygen in the blood, says Dr. Daidone. That’s because iron is an essential component of hemoglobin, which carries oxygen in the bloodstream. Not consuming enough iron can lead to anemia, in which red blood cells shrink and contain less hemoglobin. When this happens, your blood carries less oxygen. If you’re not getting enough iron from your diet, ask your healthcare provider about a supplement. It is also important to remember that red meat is high in saturated fat and cholesterol, so it should be consumed in limited amounts.
6. Get some plants
If you don’t have house plants, consider adding some to your home and office. Plants convert carbon dioxide to oxygen and act as natural air filters, capturing toxins from the air and making breathing easier.
7. Drink more water
While staying hydrated is essential for overall health, drinking water does not directly increase oxygen levels in the body, says Dr. Daidone. However, it does play a role in helping the body deliver oxygen to cells efficiently, he says. It also improves blood flow and enables you to maintain a healthy blood pressure. However, he says it does play a role in helping the body deliver oxygen to cells efficiently. What’s more, dehydration can cause mucus to build up in the lungs and become more challenging to cough out.
What to do if your blood oxygen level is too low
“Several conditions and factors can lead to low oxygen levels, including chronic obstructive pulmonary disease (COPD), anemia, sleep apnea, and high altitudes,” says Dr. Daidone. He adds that other factors, such as smoking and obesity, can also lead to low oxygen levels.
If you’re using an at-home pulse oximeter and your reading is 92% or lower, seek medical attention. If it falls below 88%, call 911 or head to the emergency room. This SpO2 level may signify hypoxemia, resulting in symptoms including but not limited to:
- Rapid breathing
- Shortness of breath
- Confusion
- Fast heart rate
Dr. Spiess adds that anyone with a lung infection, cough, fever, or chills who experiences the above symptoms or a low pulse oximetry reading should seek medical care.
To keep your lungs as healthy as possible and keep your blood oxygen levels in a healthy range, the American Lung Association recommends adopting the following lifestyle habits:
- Stop smoking and avoid secondhand smoke
- Get regular exercise
- Maintain a healthy weight
- Eat a healthy diet to support the immune system
- Stay hydrated
- See a healthcare provider for annual exams
- Keep up with flu, COVID-19, and pneumonia vaccines
- Avoid exposure to air pollution
- Improve indoor air quality
- Practice good hand hygiene
If you’re ill with a respiratory virus or chronic lung condition, you might not feel like getting out of bed. Although rest and recovery are important, Dr. Spiess emphasizes the importance of regular movement. He says that even short periods of activity will help the lungs breathe deep, cough, remove secretions, and open up the alveoli.
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