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Saturation, or oxygen saturation of the blood, indicates how much oxygen moves through our body along with red blood cells. Normal saturation levels are typically between 95% and 100% in most healthy adults. Any level below this is termed low saturation. Low saturation is a disturbing condition and requires immediate medical attention because it means that our organs, tissues, and cells are not getting the oxygen they need to function properly.
Blood oxygen saturation
To understand how the blood is saturated with oxygen, it is necessary to talk about the alveoli (Latin. alveoli of the lungs). There are millions of these microscopic “air sacs” in the lungs. They perform an important function: to exchange oxygen and carbon dioxide molecules into and out of the bloodstream.
When oxygen molecules pass through the alveoli of the lungs, they bind to hemoglobin, a substance in the blood.
As hemoglobin circulates, oxygen essentially attaches to it and is transported to the body’s tissues. This allows hemoglobin to trap carbon dioxide from the tissues and transport it back to the vesicles so that the cycle can begin anew.
Blood oxygen levels depend on several key factors:
- how much oxygen do we inhale?
- how well do bubbles convert carbon dioxide into oxygen?
- how much hemoglobin is concentrated in red blood cells?
- how well does hemoglobin attract oxygen?
Most of the time, hemoglobin contains enough oxygen to meet the body’s needs. However, some diseases reduce its ability to bind with oxygen.
Each of the blood cells contains approximately 270 million hemoglobin molecules. However, any condition that limits the body’s ability to produce red blood cells can result in low hemoglobin levels, limiting the amount of oxygen that can saturate the blood.
See also: What does low hemoglobin mean?
Low saturation – deviations from the norm
Blood oxygen levels help us find out how well our lungs, heart and circulatory system are working. The typical level of oxygen in the blood of a healthy person varies from 95% to 100%. This means that almost all red blood cells carry oxygen to cells and tissues. People who live at high altitudes or have certain types of chronic diseases, such as asthma, emphysema, or chronic obstructive pulmonary disease (COPD), have lower readings.
Low oxygen, also known as hypoxemia, is considered a reading between 90% and 92%. This low reading means that we may need extra oxygen or that problems may arise that affect our lung function. A result below 90% indicates that we should seek medical attention.
Low saturation – causes
Blood disorders, circulation problems, and lung problems can prevent your body from absorbing or transporting enough oxygen. This, in turn, can lower the blood oxygen saturation level.
Examples of conditions that can affect saturation include:
- respiratory infections (e.g. cold, flu, COVID-19) as they can affect breathing and therefore oxygen consumption;
- chronic obstructive pulmonary disease (COPD): a group of chronic lung diseases that make breathing difficult;
- asthma: a chronic lung disease which causes narrowing of the airways;
- pneumothorax: partial or complete collapse of the lung;
- anemia: lack of healthy red blood cells;
- heart disease: a group of conditions that affect how the heart works;
- pulmonary embolism: when a blood clot causes a blockage in a pulmonary artery;
- Congenital heart disease: a structural heart defect that occurs at birth.
See also: The 10 most common diseases of the circulatory system
How to measure the saturation?
Oxygen saturation is usually measured in two ways: gasometry and pulse oximetry.
Blood gas is usually only performed in a hospital setting, while pulse oximetry is performed in a variety of healthcare settings, including a doctor’s office.
Saturation test – gasometry
Blood gas is a blood test. It measures the oxygen level in the blood. It can also detect the level of other gases in the blood as well as the pH (acid / base level). Blood gas testing is very accurate, but it is invasive.
To obtain a measurement in this test, your doctor will take blood from your artery, not a vein. Unlike veins, arteries have a pulse that you can feel. The blood drawn from the arteries is also oxygenated, and the blood in our veins is not. The test uses an artery in the wrist because it is easy to feel compared to other arteries. However, the wrist is a sensitive area which makes blood sampling more inconvenient compared to the vein near the elbow. The arteries are also deeper than the veins, which increases discomfort. The sample is immediately analyzed by the machine or in the laboratory.
The results obtained from the gasometry test may give our doctor an idea of how effectively hemoglobin exchanges oxygen and carbon dioxide.
Saturation test – pulse oximetry
A pulse oximeter is a non-invasive device that estimates the amount of oxygen in your blood. It does this by sending infrared light to the capillaries of the finger, foot, or earlobe. Then it measures how much light is reflected from the gases.
The reading indicates what percentage of our blood is saturated, known as the SpO2 level. This test has a 2% error window. This means that the reading can be up to 2 percent higher or lower than the actual oxygen level in your blood. Pulse oximetry may be a little less accurate, but doctors can do it very easily.
However, it is worth knowing that, for example, dark nail polish or cold limbs may cause the test result to be lower than normal. Your doctor may remove nail polish before using the device or if the reading appears abnormally low.
Since the pulse oximeter is non-invasive, feel free to do this test yourself. Pulse monitors can be purchased from most health-related stores or online. However, it’s a good idea to talk to your doctor before using your home appliance in advance to understand how to interpret the results.
Smokers may have an inaccurately high heart rate reading. Smoking causes a build-up of carbon monoxide in the blood. A heart rate monitor cannot distinguish this other type of gas from oxygen. If you smoke and need to know your blood oxygen levels, blood gas testing may be the only way to get an accurate reading.
See also: Smoking is a disease!
Low saturation – symptoms
Low saturation can cause abnormal circulation and cause the following symptoms:
- dyspnoea;
- headaches;
- anxiety;
- dizziness;
- fast breathing;
- pain in the chest;
- confusion;
- high blood pressure;
- lack of coordination;
- blurred vision;
- feeling of euphoria;
- fast heartbeat.
If we have low saturation for a long time, we may show signs of cyanosis. The hallmark of this condition is a blue discoloration of the nail beds, skin, and mucous membranes. Cyanosis is considered an emergency. If we experience its symptoms, we should seek medical attention immediately. Cyanosis can lead to respiratory failure that can be life-threatening.
Low saturation – complications
Low saturation can affect oxygen levels in body tissues, including organs and muscles. This condition is called hypoxia.
Our cells can adapt to the lack of oxygen when the deficiency is slight. However, with larger deficiencies, cell damage can occur, followed by cell death.
Hypoxia is often caused by hypoxemia, but it can also occur when:
- there are not enough red blood cells to carry oxygen to the tissues. Possible causes include heavy bleeding from an injury or sickle cell anemia.
- insufficient blood flow. In this case, for example, it is a stroke, which occurs when the blood supply to a certain area of the brain is low, or a heart attack, when there is little blood supply to the heart muscle. Both conditions lead to cell and tissue death.
- tissues require even more oxygenated blood than can be supplied. Severe infections, leading to sepsis, can result in hypoxemia and eventually organ failure.
See also: Brain hypoxia – symptoms, effects
Low saturation – treatment
Overall, a saturation below 95% is considered an abnormal result, and anything below 90% is an emergency.
When this happens, oxygen therapy is needed – sometimes urgently. The brain is the most hypoxic organ, and brain cells can begin to die within five minutes of being deprived of oxygen. If hypoxia lasts longer, coma, seizures, and brain death can occur.
It is very important to establish the cause of low saturation to correct the problem. In chronic diseases such as COPD and asthma, the underlying cause is usually low air exchange in the lungs and alveoli. In addition to oxygen therapy, steroids or bronchodilators (rescue inhalers) may be needed to open the airways.
In circulatory conditions such as heart disease, insufficient blood flow can reduce oxygen supply. Drugs that improve heart function, such as beta blockers for heart failure or drugs for cardiac arrhythmias, can help improve oxygenation.
With anemia, the blood supply to the tissues is reduced because there are not enough healthy red blood cells with hemoglobin to carry oxygen. Sometimes a red blood cell transfusion is necessary to increase the levels of healthy red blood cells.
See also: Pharmacological coma – what is it? How is a patient put into a pharmacological coma? [WE EXPLAIN]
Low oxygen saturation – how to increase the oxygen level in the blood?
You can naturally increase the amount of oxygen in your blood. Some ways include actions that we can take ourselves.
Open a window or go outside to breathe fresh air. Something as simple as opening windows or going for a short walk increases the amount of oxygen supplied to the body, which increases the overall level of oxygen in the blood. It also has benefits such as better digestion and more energy.
Quit smoking. After just two weeks of no cigarettes, many find that both their circulation and overall oxygen levels improve significantly. During this short period of time, lung function may increase by up to 30%.
Keeping a few plants at home. Houseplants have been shown to help purify indoor air. They remove carbon dioxide and replenish the oxygen level in the room, allowing the body to absorb more oxygen.
Breathing exercises. Respiratory rehabilitation experts recommend using simple breathing exercises, such as squeezed mouth breathing and deep abdominal breathing, to open your airways and increase the amount of oxygen in your body.
We can use a pulse oximeter to check the blood oxygen levels at home and use some of these natural methods to increase the oxygen level in the blood on our own.
See also: Walking is the way to health