A person’s blood oxygen level is the main indicator of how well the body distributes oxygen from the lungs to the cells.
Most of the oxygen is carried by red blood cells (the hemoglobin protein from red blood cells), which collect it from the lungs and deliver it to all parts of the body.
The body closely monitors the oxygen levels in the blood to keep them within a specific range, so that there is enough oxygen for the needs of each cell.
What is the normal oxygen saturation level
Values above 95% are considered normal for oxygen saturation. Specifically, the closer they get to 100%, the better it is for the body and the health of its organs.
A value below 95% of oxygen saturation indicates that the person’s health must be closely monitored, and when the values fall below 90%, there’s an immediate need of emergency medical care or mechanical ventilation.
How is blood oxygen measured?
There are multiple effective ways to monitor blood oxygen levels.
Blood test to measure oxygen saturation
You can find out your oxygen blood levels by having a test called blood gas or ABG.
For this test, a blood sample is taken from an artery, usually from the wrist (the procedure is very precise, but can be a little painful). The main disadvantage of this test is that you’re required to visit a health care provider.
Pulse oximetry
Pulse oximetry is a noninvasive test that measures the oxygen saturation level of your blood by having a small device attached to a finger (sometimes to an earlobe though the accuracy of this method is unknown).
The pulse oximeter indirectly measures oxygen in the blood by absorbing light through a person’s pulse.
Although the use of a pulse oximeter is easier, faster and painless, the accuracy can be influenced by factors such as dirty fingers, strong lights or nail polish/fake nails.
Why is it useful to know your oxygen saturation?
Knowing the oxygen saturation is useful, especially in diseases affecting the lungs or the entire respiratory or circulatory system, including the recent pandemic-responsible virus, COVID-19.
When oxygen saturation drops below 93%, the proteins synthesized by the body in response to inflammation begin to take over the air sacs in the lungs, and oxygen no longer reaches the blood.
Moreover, the organs are no longer properly oxygenated and various processes are triggered that might irreparably impact the body and can ultimately lead to death.
Low blood oxygen levels can be a sign that your condition is getting worse, even before it causes noticeable symptoms such as severely affecting your breathing.
Here’s how to interpret values of oxygen saturation levels:
95 to 100 – Safe level values
93 or 94 – Check your blood oxygen level again within an hour, especially after a short walk around the room; if it is still 93 or 94, call emergency services or your family doctor for advice;
92 or less – Check your blood oxygen level again immediately – if level 92 persists or decreases, go to a hospital emergency room immediately.
Why does oxygen saturation decrease?
A low level of oxygen saturation in the blood is called hypoxemia and this can be triggered by various medical conditions, including but not limited to:
- Heart disease, including heart abnormalities
- Asthma
- Sleep apnea
- Pneumonia
- Emphysema
- COPD
- Bronchitis
- Severe anemia
- Elevated altitude
Symptoms of low oxygen saturation
When oxygen saturation is low, various hard-to-ignore symptoms begin to appear:
- Bruising of the tongue, lips, face, and extremities (fingers, nails)
- Cold extremities – this symptom might not be a clear indication of oxygen level issues in people suffering from cold hands and feet every day.
- Impaired memory and concentration
- Increased heart rate
- Coughing
- Shortness of breath, with a feeling of suffocation
- Dizziness
- Intense headache
- Sleepiness
- Loss of consciousness
8 Interesting Facts about Breathing and the Respiratory System
- Paradoxically, we need to breathe not to receive oxygen but to eliminate carbon dioxide from the blood.
- Mouth breathing can, over time, create shrinkage of the jaw – resulting in crooked teeth (even after wearing braces). That is why it is important to learn to breathe correctly through the nose and, if necessary, fix septum deviation through surgery..
- Lungs are the only body organs that can float thanks to the air that is contained within their alveoli.
- Lungs contain approximately 2,400 kilometres of airways and between 300 to 500 million air sacs (alveoli).
- The more often you breathe (hyperventilation) the hungrier you will feel and the more acidic your body will become.
- Breathing should be done only at the intensity in which you can keep your mouth closed.
- The nose has a 4-stage filtration system. Breathing through the mouth, air and all the particles it contains skips directly to the 4th stage and this can easily lead to sore throat, tonsillitis and even ear infections.
- Just like any other muscles in the body, the inspiratory muscles (mainly the diaphragm) weaken with age, when underused or used in the wrong way.