What Are the Normal SpO2 Levels?

Blood oxygen saturation level, or SpO2 for short, can be an important indicator of overall health. Measured as a ratio of the red blood cells in your body that carry oxygen to your total red blood cell capacity, SpO2 shows how efficiently your heart, lungs, and circulatory system can transport oxygen around your body.

Since oxygen is necessary for your body, it’s important to ensure that your blood oxygen level is within the optimal range. 

When the SpO2 levels in your blood are consistently low, it is known as hypoxemia. This can indicate an underlying condition affecting your ability to take in and transport oxygen.


How Do You Measure SpO2?

The most common way to measure blood oxygen levels is using a device called a pulse oximeter. Pulse oximeters are noninvasive. It is clipped onto a body part, usually the middle finger of the dominant hand. One side shines red and infrared LEDs through a relatively transparent portion of the skin, usually where there is good blood flow, while the other side receives that light. The amount of absorbed light will differ depending on the percentage of oxygen in your blood.


Who Can Use a Pulse Oximeter?

Pulse oximetry is an invaluable tool for medical professionals when treating patients and can also be useful for monitoring your SpO2 levels at home for low blood oxygen levels. 

However, it’s important to remember that the readings can be prone to error, especially when some factors are involved (e.g., nail polish, constant movement, and unreliable devices). Low readings are especially serious when accompanied by physical symptoms, such as shortness of breath, discoloration of extremities, or lightheadedness.



Healthy SpO2 Levels by Age


Normal SpO2 for Babies

For babies, the optimal SpO2 range is between 95% and 100%. Many babies, particularly newborns, have lower oxygen saturation measurements, hovering between 90% and 95%. This is perfectly normal, especially since infants under 2 have relatively low activity levels.

If you are concerned, you can speak to your doctor about your infant’s blood oxygen levels. However, it’s also important to remember that babies not born prematurely rarely suffer from impaired breathing and dangerously low SpO2.


Normal SpO2 for Kids

Children between the ages of 3 and 12 typically have an SpO2 range between 95% and 100%; anything lower may be cause for further medical attention.


Normal SpO2 for Teens

Like younger children, teens ages 13 to 19 have a similar SpO2 range, and their pulse oximetry readings are generally higher than 95%.


Normal SpO2 Range for Adults

Most adults have an SpO2 level between 95% and 100%, with the majority in the 97% and higher range. Your levels may fluctuate throughout the day as your activities change but typically stay within this range as your body automatically adjusts to maintain a normal blood oxygen level.


Normal SpO2 for Seniors

Again, older adults ideally have an SpO2 readings higher than 95%, but older adults also tend to have lower measurements than younger adults. 

Having an average SpO2 level that hovers around 93% or 94% is likely nothing to be concerned about, especially if it’s normal for you and not accompanied by any breathing problems.


Healthy Blood Oxygen Levels for Other Populations


Your SpO2 levels can often vary based on factors other than age, such as your activity level and health conditions affecting breathing rate and circulation.


SpO2 Rates for Runners

Cardio-based exercises such as running are often thought to improve overall circulation and heart and lung performance. While this is usually true, you may not know that it’s common for your oxygen saturation levels to drop right after a dramatic increase in activity. 

This is because your cells suddenly need increased oxygen, and your heart and lungs have not yet adjusted to this increase. The result is that your SpO2 can drop from 1% to 3%, but your body quickly compensates and returns your low oxygen levels to normal.  However, if you begin to suffer symptoms of hypoxemia, you should cease exercising and consider seeking medical attention.


SpO2 Rates for Climbers

Much of what is true for the oxygen levels of runners is also true for climbers. However, climbers should also be aware that SpO2 levels can vary due to altitude heights.

While the exact normal oxygen levels at different altitudes are not easy to determine due to a range of factors, it’s typical for your SpO2 to drop when you’re high above sea level, sometimes by as much as 5% to 8%. Most of us already know that high altitudes result in less oxygen in the air, and your body adjusts to these differences quickly.

If you’re climbing at high altitudes, you must factor in the possibility of low blood oxygen. You may not be able to climb as far or as quickly as you might at a lower altitude.



SpO2 for Sleep Apnea

Sleep apnea results in paused breathing while sleeping, which can often affect blood oxygen levels and blood pressure. While sleeping, your breathing rate slows, so oxygen levels of 90% to 95% are considered normal, but pauses in breathing due to sleep apnea can cause your SpO2 to drop as low as 86% to 89%.

The frequency and length of these pauses will determine the severity of your sleep apnea. Decreased oxygen levels while sleeping can result in drowsiness and irritability during the day, as well as headaches and memory problems. If you want to measure your SpO2 while you sleep, smartwatches that provide pulse oximetry results may be a great preliminary option.


Sleep apnea has a variety of treatments, and nighttime oxygen supplementation may be one of them. Talk to your healthcare provider and consider visiting a sleep specialist if you believe you have sleep apnea.


Normal SpO2 for COPD Patients

Living with chronic obstructive pulmonary disease, or COPD, often means that your blood oxygen levels are lower than normal, hovering anywhere from 88% to 92%.

Because of this, pulse oximeters have been shown to be somewhat unreliable in clinically diagnosing and monitoring COPD. Some studies have shown that pulse oximeters are less accurate at low oxygen saturations than their invasive counterparts—arterial blood gas tests.

For frequent home use, pulse oximetry can still be a useful frontline indicator of stable oxygen levels. 


SpO2 Levels for Asthma Patients

Measuring oxygen saturation levels for asthmatic patients can be deceptive, as the SpO2 levels in those with asthma are often compensated extremely well despite their symptoms. This means someone can have a moderate or severe asthma attack while maintaining a blood oxygen level above 90%.

Immediately before respiratory failure, a pulse oximeter may reflect a sudden drop in oxygen level. However, if you’re experiencing severe asthma symptoms and normal pulse oximeter readings, you should still seek medical attention for your symptoms.


Normal SpO2 Level for Diabetic Patients

The intersection of diabetes and circulatory issues means that pulse oximeters can be a useful tool for diabetic patients. Monitoring your SpO2 to ensure that your blood oxygen level stays above 95% can lower your risk of suffering from undetected peripheral vascular disease (PVD).

However, pulse oximetry can have its limitations. For Type 2 diabetics with poor glycemic control, pulse oximeters have been shown to overestimate arterial oxygen saturation, something to keep in mind if you’re relying on an oximeter. 


What Is the SpO2 for COVID-19?

COVID-19 often causes low oxygen levels, and patients with moderate to severe cases often require supplemental oxygen. While using a pulse oximeter is not a recommended method for diagnosing COVID-19, it can be a helpful way to monitor symptoms. 


Contacting your health provider as soon as you feel shortness of breath while resting or if your pulse oximeter reading drops below 92% can ensure you receive the necessary treatment before suffering from severely low oxygen saturation.


Typical SpO2 for Cystic Fibrosis

Cystic fibrosis is an inherited lung disease that causes the airways to fill with mucus, inhibiting the body’s ability to take in oxygen. The condition can be treated but not cured. Early diagnosis with the help of newborn screenings can improve one’s chances of managing the disease.

Patients with cystic fibrosis often have a resting oxygen level that is 3% to 4% lower than average. Patients with cystic fibrosis can use pulse oximeters as a helpful indicator of overall blood oxygen saturation and how well treatment is performing.


SpO2 for Heart Patients

Many heart conditions can lead to low blood oxygen levels due to impaired heart performance. SpO2 levels can be an important indicator of how affected your heart is by heart disease or other heart conditions. Healthcare providers often monitor a heart patient’s oxygen level, and the risk of heart failure may be suspected if readings are below 90% to 93%


SpO2 for Shock Patients

Septic shock is a condition that occurs when blood pressure drops to extremely low levels. It is life-threatening and can lead to multiple organ failure. Cardiac monitoring, noninvasive blood pressure monitoring, and pulse oximetry are all used to monitor patients suffering from septic shock. 

The oxygen level of a patient suffering from septic shock is an important indicator of mortality risk. A recent study showed that non-survivors had average SpO2 levels of 73% while survivors were more than 10% higher. Emergency treatments for septic shock may include supplemental oxygen, IV fluids, and antibiotics.


SpO2 for Hypoxia

Hypoxia occurs when the levels of oxygen in your blood have gotten so low that it begins to affect the oxygenation of your tissues. Hypoxia typically occurs when your pulse oximeter measures an SpO2 of less than 90%.

One major symptom of hypoxia is cyanosis, or when your extremities begin to darken due to low oxygen levels. However, this may be difficult to notice, especially if your skin is already of a darker tone. Other early signs of hypoxia are fatigue and numbness in extremities. More severe symptoms include twitching, disorientation, hallucinations, pallor, and irregular heartbeat.

If you suspect that you’re experiencing hypoxia, you should seek medical attention immediately. The effects of hypoxia tend to worsen exponentially and can result in death if untreated. 




While there are many ways to measure oxygen level, pulse oximetry is one of the most common and cost-effective. Pulse oximeters measure oxygen saturation using an infrared image transmitted through the fingertip. The device also measures various respiratory parameters like heart rate and SpO2. Patients with COPD, asthma, diabetes, cystic fibrosis, heart disease, and shock will all benefit from monitoring their oxygen level when measuring SpO2.