Understanding Low and Normal Blood Oxygen Levels
Blood oxygen saturation is measured in millimetres of mercury (mm Hg). A reading below 60 mm Hg may indicate insufficient oxygen levels in the body, which may cause fatigue, dizziness, and shortness of breath.
When the amount of oxygen in the bloodstream falls between 75–100 mm Hg, it can indicate a healthy oxygen level in the body. However, if the level drops below 60 mm Hg, inadequate oxygen may reach the body's essential organs, leading to a range of symptoms.
The body vigilantly regulates the amount of oxygen in the blood to ensure adequate supply for the body's cells. This is monitored closely to keep the oxygen levels within an optimal range.
The amount of oxygen in a person’s bloodstream can provide insight into how effectively oxygen is transported from the lungs to the cells. Monitoring a person’s blood oxygen level can benefit their health and well-being.
Normal vs Low Blood Oxygen Levels
The blood oxygen level is healthy when it falls between 75 and 100 millimetres of mercury (mm Hg).
If the oxygen level in an arterial blood gas (ABG) test is lower than 60 mm Hg, medical professionals consider it low. In such cases, supplemental oxygen may be necessary to bring the oxygen level to a normal range.
Hypoxemia occurs when the oxygen levels in the blood are lower than the usual rate for a healthy individual. This happens when the body cannot provide enough oxygen to its cells, tissues, and organs.
Normal and Low Blood Oxygen Levels Compared
| Measurement | Normal Range | Low Range | Health Meaning | What to Do |
|---|---|---|---|---|
| Arterial Blood Gas (ABG) | 75–100 mm Hg | Below 60 mm Hg | Indicates how well lungs transfer oxygen | Seek medical assessment or oxygen therapy |
| Oxygen Saturation (SpO₂) | 95–100% | Below 95% | Mildly low oxygen level | Monitor and review with a doctor |
| Severe Low Level | Below 90% | Very low oxygen supply | Risk of organ damage or hypoxemia | Seek urgent medical help |
What Oxygen Saturation Means
A pulse oximeter is attached to a person's fingertip and is used by medical professionals to measure a person's oxygen saturation, which is the amount of oxygen in a person's blood. It can be used for either a one-time test or for continuous monitoring.
Oxygen saturation levels considered healthy are anywhere from 95-100%. When oxygen saturation levels drop below this range, people may experience difficulty breathing, confusion, and other symptoms of lack of oxygen.
Symptoms of Low Blood Oxygen
An ABG test is a reliable method for assessing the oxygen content of blood. It involves obtaining a blood sample from an artery, typically in the wrist, and is considered an accurate method, although it may cause some discomfort.
Although ABG tests are typically conducted in a hospital, people can measure their oxygen saturation levels at home using a pulse oximeter. However, ABG tests are not something that people can do themselves at home.
A pulse oximeter is a small device used to measure the amount of oxygen in the blood. It is typically clipped onto a finger, although it can also be used on an ear or a toe. The device uses light absorption to detect the oxygen levels in the person's pulse.
Although the pulse oximeter test is more convenient and less invasive than the ABG test, it is less reliable.
- Bright lights
- Nail polish
- Darker skin tones
- Poor circulation to the extremities
- Dirty fingers
Symptoms Of Low Blood Oxygen Levels
Abnormal circulation caused by low blood oxygen levels can lead to various symptoms.
- Restlessness
- Sense of euphoria
- Confusion
- Shortness of breath
- Headaches
- Chest pain
- High blood pressure
- Visual disorders
- Rapid breathing
- Dizziness
- Lack of coordination
- Rapid heartbeat
Causes of Low Blood Oxygen Levels
A condition in which there is a decrease in the level of oxygen in the blood is known as hypoxemia.
- A shortage of oxygen in the atmospheric air.
- The lungs' incapacity to draw in and distribute oxygen to all cells and tissues.
- The bloodstream's inability to flow to the lungs gathers oxygen and conveys it throughout the body.
Medical Conditions That May Cause Hypoxemia
Contributing factors to the conditions mentioned earlier include several medical conditions and situations.
- Asthma
- Heart conditions, including congenital heart disease
- High-altitude environments
- Anemia
- COVID-19
- Chronic obstructive pulmonary disease (COPD)
- Interstitial lung disease
- Emphysema
- Acute respiratory distress syndrome (ARDS)
- Pneumonia
- Pulmonary artery blockage
- Pulmonary fibrosis, characterised by lung scarring and damage
- Pneumothorax, the presence of air or gas causing lung collapse
- As a result of fluid accumulation in the lungs, pulmonary oedema occurs
- Sleep apnea, involving breathing interruptions during sleep
- Medication, such as narcotics and pain relievers.
When to See a Doctor About Oxygen Levels
People need to seek medical attention if they experience:
- Encounter intense and abrupt breathlessness.
- Encounter breathlessness even when at rest.
- Face severe breathlessness that intensifies during physical exertion or exercise.
- Awaken suddenly with breathlessness or a sensation of choking.
- They are situated at high altitudes and experience severe breathlessness and symptoms like coughing, rapid heart rate, and fluid retention.
How Low Blood Oxygen Is Treated
To address low oxygen levels in the blood, a doctor may suggest supplemental oxygen therapy. This therapy can be administered in a doctor's office, or they may prescribe oxygen therapy at home (HOT).
Prescription-strength devices are available for delivering and monitoring Heat-Oxygen Therapy (HOT), while others do not require a prescription.
People can change their lifestyles to reduce the symptoms of low oxygen levels and improve overall health and quality of life. These changes could include
- Avoiding secondhand smoke
- Exercising regularly
- Quitting smoking
- Consuming healthy foods such as fruits, whole grains, lean proteins, and vegetables
Long-Term Outlook for Low Oxygen Levels
Chronic pulmonary diseases, such as COPD, as well as COVID-19 should be monitored regularly, as these conditions can cause the oxygen levels to drop. Treating the underlying disease should help raise the blood's oxygen levels.
Oxygen therapy and modifications to diet and exercise regimes can help a person with low blood oxygen increase their oxygen saturation levels. Lifestyle changes can be beneficial and should be taken into consideration.
Summary: Monitoring and Improving Oxygen Levels
A person's oxygen saturation, or the amount of oxygen in their blood, can be determined with a pulse oximeter. When measuring oxygen saturation, physicians consider levels below 95% to be low.
Asthma, anaemia, and COVID-19 can lead to low blood oxygen levels. Treatment usually addresses the underlying condition, but doctors may suggest oxygen therapy or lifestyle changes.
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