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8 Factors that May Lower Oxygen Levels + Tests

Written by Joe Cohen, BS | Last updated:
Medically reviewed by
SelfDecode Science Team | Written by Joe Cohen, BS | Last updated:

Scientists think that low oxygen levels or hypoxia can cause problems with the mitochondria and the brain. Read this post to learn the science behind factors that may lower oxygen levels.

Why Does Oxygen Matter?

Mitochondria and cAMP

Mitochondria need oxygen.

According to some yet-to-be-verified theories, mitochondrial problems may be at the heart of all chronic diseases. We still have lots to learn about the workings of the mitochondria, though. Plus, complex diseases always involve multiple possible factors – including biochemistry, environment, health status, and genetics – that may vary from one person to another.

We know that when mitochondria are working well, they build up healthy levels of ATP and NAD+ levels, which are important for energy utilization and metabolism. That’s how mitochondria became known as the “powerhouses of cells” [1, 2].

ATP converts to cyclic AMP, which is a critical messenger molecule for so many cellular processes. cAMP is needed for the regulation of glycogen, sugar, and lipid metabolism [3].

Research suggests that the following hormones also require adequate cAMP levels to function optimally: FSH, LH, ADH, TSH, CRH, hCG, ACTH, MSH, PTH, GHRH, Glucagon, and Calcitonin [4].

Read why NAD+ is important.

The body also fights infections with the superoxide that’s created from oxygen [5].

Thus, a person’s health and energy, in part, depend on how much oxygen they have and how well their mitochondria utilize it.

Now there’s obviously more to the story, but you want to make sure the fundamentals are right.

Measuring Oxygen Levels

If you want to measure your oxygen levels, speak to your healthcare provider. They will recommend the best method based on your health status. Make sure to ask any questions you have about the procedures.

Pulse Oximeters

A pulse oximeter is a small device that clips to a finger. It is described by some as the easiest method to measure blood oxygen.

Doctors will usually use pulse oximetry to assess oxygen levels in people with heart disease, lung disease, anemia, or cancer. It can also be used to monitor health in people taking lung medication, during or after surgery with general anesthesia, to measure physical capacity and breathing, and to check for sleep apnea [6]

People think that oxygen levels can be measured directly with a pulse oximeter. However, these devices measure what percentage of hemoglobin, the protein in blood that carries oxygen, is loaded with oxygen [7].

They know this by measuring the number of red vs infrared that gets absorbed in the tissue. Oxygenated hemoglobin absorbs more infrared light and allows more red light to pass through.

However, this doesn’t measure the number of red blood cells and hemoglobin. Thus, these devices provide an indirect estimate of oxygen levels

They also don’t measure how much blood a person has in a given area, especially the brain.

The normal range of pulse oximeters usually ranges from 95 to 100%. Values under 90% are typically considered low. Some people have suggested that values over 99% are better for optimal function, but there are no data to back this up.

Arterial Blood Gas Test

Hypoxemia is most precisely determined by measuring oxygen levels in arterial blood – called arterial blood gas or ABG.

However, this test is a little more difficult to perform compared to other standard tests, since it requires a blood sample from the artery, which can be more painful and potentially has more complications compared to drawing blood from the veins [8, 9].

Lab results are commonly shown as a set of values known as a “reference range”, which is sometimes referred to as a “normal range”. A reference range includes the upper and lower limits of a lab test based on a group of otherwise healthy people.

The normal range for arterial oxygen is Normal arterial oxygen is about 75 to 100 millimeters of mercury (mm Hg). Values under 60 mm Hg are usually considered low and may indicate oxygen therapy.

Your healthcare provider will compare your lab test results with reference values to see if any of your results fall outside the range of expected values. By doing so, you and your healthcare provider can gain clues to help identify possible conditions or diseases.

Some lab-to-lab variability occurs due to differences in equipment, techniques, and chemicals used. Don’t panic if your result is slightly out of range – as long as it’s in the normal range based on the laboratory that did the testing, your value is normal.

However, it’s important to remember that a normal test doesn’t mean a particular medical condition is absent. Your doctor will interpret your results in conjunction with your medical history and other test results.

Have in mind that a single test isn’t enough to make a diagnosis. Your doctor will interpret this test, taking into account your medical history and other tests. A result that is slightly low/high may not be of medical significance, as this test may vary from day to day and from person to person.

Other Blood Tests

Other blood tests may hint at hypoxia, but they are not used to estimate oxygen levels in the blood. Rather, doctors may order them to find additional clues.

Some examples include:

  • Complete Blood Count
  • Hematocrit
  • Iron levels

Red blood cells carry hemoglobin, which carries oxygen. The more red blood cells a person has, the more they can carry oxygen.

Hemoglobin actually carries the oxygen. The more hemoglobin someone has, the more oxygen they transport.

Hemoglobin comprises about a third of the total red blood cell volume. This protein is responsible for the transport of more than 98% of the oxygen (the remaining oxygen is carried dissolved in the blood plasma).

Hematocrit is a blood test that measures the percentage of the volume of whole blood that is made up of red blood cells. This measurement depends on the number of red blood cells and the size of red blood cells.

Red blood cells and hemoglobin are the most important info in Complete Blood Count readings tied to hypoxia.

Low iron or iron stores may also cause less oxygen utilization because oxygen binds to iron-containing molecules (heme) in hemoglobin. Low RBC and hemoglobin often reflect an iron deficiency.

A low RBC or hemoglobin count may indicate that your erythropoietin (EPO) may be low. Hemoglobin holds oxygen and RBCs hold hemoglobin. EPO helps produce both. Some scientists think that EPO is important for mood and memory independent of its effects on RBCs, but more research on these effects is needed [10].

Blood Pressure

Some people may have good RBCs, hemoglobin, and oxygen saturation, but their issues may arise from poor blood flow, especially to the brain [11, 12].

Blood pressure is one measure of blood flow. Science suggests that higher blood pressure can indicate that the blood is more viscous, thick, and prone to clogging, which will require more force and pressure to move it. It can indicate blood vessels that are hardened and unable to relax easily. It can indicate lower nitric oxide. In most cases, the exact cause of high blood pressure is unknown [13].

Low blood pressure means that blood is not flowing with a certain force level, in which case it may not reach the brain. The brain compensates for low blood pressure, but only to an extent [R].

Studies suggest that excessively low blood pressure – such as during prolonged surgeries under general anesthesia – may cause problems with brain circulation. Brain imaging is needed to determine this precisely, though [14].

Blood pressure of 90/60 or under is usually considered low, while normal pressure should be in the range of 110-120/70-80.

Additionally, if you feel you have cold hands or feet, it might be a symptom that blood isn’t going to your peripheral body areas. This may also be an indicator of hypothyroidism (underactive thyroid) and low T3 [15].

In an interview, Dr. Pollack argues that EZ water can improve blood flow. Clinical data are lacking to support his claims, though.

Oxygen Utilization Research

Assuming everything set up to this point is functioning normally in the body, scientists think that it’s still possible not to have enough neuronal NOS and endothelial NOS that will diffuse the oxygen from the circulation into the cells. Their exact impact in humans has yet to be specified, though [16, 17].

In animal studies, UV increases nitric oxide and the relaxation of blood vessels [18].

Scientists are investigating whether UV light can increase free endothelial NOS or eNOS (in vessels/capillaries), total neuronal NOS or nNOS (in neurons) [19, 20], and nitric oxide through other means [18]. In theory, this would allow oxygen to better diffuse into tissues, but more research is needed [21].

nNOS is also important for gut flow and sexual arousal in both men and women. In fact, many natural aphrodisiacs are thought to act by boosting NO [22].

Potential Causes of Hypoxia

Causes shown here are commonly associated with hypoxia/low oxygen levels. Work with your doctor or other health care professional for an accurate diagnosis.

1) Anemia

Your bloodstream must be able to take oxygen from your lungs and carry it to your tissues. People with anemia have low hemoglobin, which means that their oxygen-carrying capacities are reduced.

2) Lung and Nasal Problems or Mucus

To keep your oxygen levels normal, your lungs must be able to inhale enough oxygen and exhale carbon dioxide.

Asthma, COPD, pneumonia, lung scarring, and many other respiratory diseases that affect the lungs are a common cause of hypoxia.

Additionally, people who have nasal blockage may have difficulty breathing, though this is usually much less severe than lung diseases. However, if you have severe problems breathing through your nose (such as a deviated septum) or constant mucus, talk to your doctor to see how your breathing difficulties could be impacting your health and oxygen levels.

3) Obstructive Sleep Apnea

Sleep apnea can lower oxygen levels since it causes people to stop breathing several times during the night. If you think you have sleep apnea, see a qualified doctor to get assessed and diagnosed. Your doctor may recommend that you enroll in a sleep study, which measures oxygen drops while you’re sleeping.

4) High Altitude

Living in an elevated location like Colorado or Utah can contribute to hypoxia. People who live in elevated locations often have higher RBCs and hemoglobin to make up for lower blood saturation.

5) Heart Disease

Inborn heart defects in children and adults are a possible cause of low oxygen levels. In this case, the heart is not able to pump blood effectively, so not enough oxygen can reach tissues.

6) Lower Blood Pressure and Poor Circulation

Limited studies suggest that low blood pressure can reduce oxygen levels, and inflammation may be involved. Inflammation and cytokines increase iNOS, which produces large quantities of Nitric Oxide (as opposed to eNOS and nNOS) [22].

Studies point out that iNOS usually occurs with high levels of oxidative stress, and thus high levels of NO have the opportunity to react with superoxide leading to peroxynitrite formation and cell toxicity [22].

Very high levels of uncontrolled nitric oxide through increased iNOS decreases smooth muscle contractions by the heart and lead to lower blood pressure [22].

Nitric oxide from iNOS is thought to be more systemic rather than localized where you need increased blood, which is how eNOS and nNOS are hypothesized to work. Hypoxia locally in the brain may contribute to cognitive problems [23].

7) Psychological Stress

According to some researchers, low oxygen may also be caused by a sympathetic or fight or flight system that is in overdrive. This, in turn, changes breathing. For example, people under stress tend to breathe shallowly. People with anxiety often hyperventilate [24, 25].

It may be a good idea to be more mindful of your breathing. Some people say that 5-6 breaths per minute is a balanced breathing pattern.

Some people who are under stress have normal blood pressure and heart rate (115/75 and 55-70). However, they tend to have low heart rate variability (HRV). HRV is an indicator of vagus nerve function.

8) Chronic Inflammation

Scientists think that there’s complex cross-talk between hypoxia and inflammation. According to them, low oxygen may be caused, in part, by cytokines and other inflammatory messengers, which may prevent oxygen from reaching the tissues from capillaries [26].

Many of the diseases mentioned above-such as heart disease, COPD, asthma, and sleep apnea–involve chronic inflammation. However, further research should pinpoint causes and the exact pathways inflammation and hypoxia use to communicate.

Lack of Sunlight?

The exact impact of sunlight on oxygen levels has yet to be determined. It’s uncertain whether a lack of sunlight can contribute to hypoxia since human data are lacking.

In animals, UV increases nitric oxide and the relaxation of blood vessels [18, 19, 20], which allows oxygen to diffuse into tissues better [21].

More research is needed.

Natural Factors that May Increase Oxygen

These are being researched for increasing EPO in animals:

However, human data are lacking to support their use.

Do not use any device or supplement without consulting your doctor first.

Despite a lack of evidence, people also sometimes use the following devices to increase oxygen:

  • Breathing Exerciser
  • Oxygen Concentrator
  • ICES, which allegedly increases tissue oxygenation

About the Author

Joe Cohen, BS

Joe Cohen, BS

Joe Cohen flipped the script on conventional and alternative medicine…and it worked. Growing up, he suffered from inflammation, brain fog, fatigue, digestive problems, insomnia, anxiety, and other issues that were poorly understood in traditional healthcare. Frustrated by the lack of good information and tools, Joe decided to embark on a learning journey to decode his DNA and track his biomarkers in search of better health. Through this personalized approach, he discovered his genetic weaknesses and was able to optimize his health 10X better than he ever thought was possible. Based on his own health success, he went on to found SelfDecode, the world’s first direct-to-consumer DNA analyzer & precision health tool that utilizes AI-driven polygenic risk scoring to produce accurate insights and health recommendations. Today, SelfDecode has helped over 100,000 people understand how to get healthier using their DNA and labs.
Joe is a thriving entrepreneur, with a mission of empowering people to take advantage of the precision health revolution and uncover insights from their DNA and biomarkers so that we can all feel great all of the time.


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