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Low Oxygen Symptoms: Signs You May Not Be Getting Enough Oxygen

Oxygen is one of the most abundant elements in the universe, which makes it a bit ironic, then, that people with breathing problems are unable to get enough of it. The body needs to maintain a normal oxygen level, which requires a certain amount of circulating oxygen in the blood at all times to effectively nourish the cells, tissues and organs. When blood oxygen levels drop below normal, a condition known as hypoxemia may occur. 

Hypoxemia is an abnormally low blood oxygen level, which can have many causes and consequences. Hypoxemia can be acute, occurring suddenly because of an emergency situation like high altitudes or a blood clot in the artery of a lung. It can also be chronic, taking place over time because of a long-term health condition like COPD or pulmonary fibrosis. With a lack of oxygen in the body, symptoms can become uncomfortable at first, then worrisome and eventually they can become life-threatening. Hypoxemia is the main reason that people with COPD and other lung diseases are prescribed supplemental oxygen. Unfortunately, many people with COPD assume that their symptoms are part of their disease and continue to assume they are maintaining a normal oxygen level. Often, they are unaware that they are hypoxemic and, unless prompted to do so for another reason, they might not immediately seek medical attention. However, when there is a lack of oxygen in the body, symptoms can progress quickly. This can be dangerous because hypoxemia associated with COPD contributes to a reduced quality of life, impaired skeletal muscle function, decreased exercise tolerance and an increased risk of death.[1] 

If you or a loved one have COPD or another chronic illness that puts you at greater risk for low oxygen levels and hypoxemia, it is important that you are able to recognize the signs and symptoms of lack of oxygen so that appropriate action can be taken if, or when, it occurs. Here are the symptoms of low oxygen levels, as well as how to check your oxygen saturation level at home.

Symptoms of Low Oxygen in Blood (Hypoxemia)

Low oxygen symptoms of hypoxemia vary depending upon its severity. If you or a loved one experience any of the symptoms listed below, contact a health care provider as soon as possible. If you experience more than one of the following symptoms of low oxygen levels, seek medical attention immediately:


  • Confusion: Mild confusion can be one of the earlier signs of hypoxemia and can manifest as a change in typical behavior, inattention, disorganized thinking and altered alertness. As hypoxemia progresses, so will the confusion.[2]
  • A sense of euphoria: A sense of euphoria can occur as hypoxemia progresses to hypoxia and can appear similar to intoxication. There may be changes in appearance, behavior, rate and continuity of speech, mood or even hallucinations and abnormal beliefs about time, location or people. Judgment, memory and insight may be impaired.[3]
  • Restlessness: One of the earliest signs of hypoxemia is restlessness (often accompanied by anxiety). It may be difficult to rest, relax or concentrate, and can eventually progress to agitation.[4]
  • Headache: When insufficient amounts of oxygen reach the brain, headaches are common and can be an early indicator of hypoxemia. 
  • Shortness of breath: Shortness of breath, or dyspnea, is one of the more common signs of hypoxemia. Shortness of breath feels like being winded, or struggling to get enough breath. Shortness of breath may also include a tight sensation in the chest, rapid breathing or feeling unable to get enough oxygen.[5] Pursing lips or flaring nostrils while breathing may also occur.[4]
  • Rapid breathing: Also called tachypnea, a rapid respiration rate is typically accompanied by shortness of breath, and the sensation of needing to breathe more or faster than normal. Both of these conditions indicate respiratory distress.[4][5]
  • Dizziness, lightheadedness and/or fainting spells: Feeling dizzy or lightheaded and/or fainting is a common indication that your body is not getting the oxygen it needs. A floating feeling or feeling the frequent need to yawn may also occur.[6]
  • Lack of coordination: A slowing in motor speed and altered hand coordination are common signs of hypoxia, or insufficient oxygen in the tissues, which can be caused by hypoxemia.[7] 
  • Rapid heart rate: Increases in heart rate, or the sensation of the heart racing, can occur as the body attempts to compensate for the low levels of oxygen in the blood.[8]
  • Elevated blood pressure: Also called hypertension, elevated blood pressure is a common symptom of hypoxemia and is often a sign that hypoxemia has progressed.[9] 
  • Visual disturbances: Changes in vision, like tunnel vision, can be indicative of hypoxemia and may indicate progression to hypoxia.[10]
  • A bluish tint to the lips, earlobes and/or nail beds (cyanosis): This is a sign of severe hypoxemia, indicating that your cells are not getting enough oxygenated blood. Cyanosis should be taken extremely seriously and warrants emergency medical care.[8]
  • Elevated red blood cell count or polycythemia: If hypoxemia is a long-term problem, the body may overproduce red blood cells, which causes the blood to become thick, restricting its ability to travel through smaller blood vessels. This may cause additional symptoms, including burning sensations in the extremities, ringing in the ears and itching.[11]


Monitoring Oxygen Levels at Home

For many patients experiencing a lack of oxygen in the body, symptoms may require that patients check themselves for hypoxemia at regular intervals. In these cases, a pulse oximetry monitor plays an important role in the home monitoring of patients with lung disease.[12] Whether you are using supplemental oxygen or not, a pulse oximetry monitor is an excellent tool for measuring oxygen saturation and helping to maintain a safe and normal oxygen level for you. In fact, along with blood pressure, pulse, respirations and temperature, oxygen saturation is now considered to be the fifth vital sign in many institutions.[13]

A pulse oximeter is a non-invasive device that measures the oxygen saturation of hemoglobin in the blood using red and infrared light. Because it is able to easily and rapidly detect changes in oxygen saturation, it can provide a warning to patients and health care providers alike of impending or existing hypoxemia.[13] For patients using supplemental oxygen, this can help them and their health care team learn when they need to use supplemental oxygen and when it is most effective for maintaining healthy oxygen levels. Patients who learn to use a pulse oximeter at home are better able to communicate a lack of oxygen in the body, symptoms that may result from low oxygen levels and the situations that seem to cause the low oxygen levels to their health care team. This can help both the patient and health care providers get a more accurate picture of the patient’s hypoxemic episodes, allowing health care providers to offer the best possible treatment solutions.

Normal oxygen saturation levels run between 95% and 100%, but it is typical for patients with lung disease to have a lower than normal oxygen level. However, even if it is typical for a patient, with a lack of oxygen in the body, symptoms will continue to progress. Regardless of what is normal for a patient, once oxygen saturation levels drop consistently to 88% and below at rest, a patient should be evaluated for supplemental oxygen therapy to help improve overall oxygen levels.[14]

What to Do if Oxygen Saturation Levels are Low

If you are not already using supplemental oxygen and you are experiencing symptoms of hypoxemia and/or low oxygen saturation levels, do not wait to contact your health care provider immediately. If you have low oxygen levels, you might want to see about being evaluated for long term oxygen therapy. Oxygen therapy is appropriate for improving your blood oxygen level and can be effective for many conditions that cause hypoxemia, COPD included.

If you are a current user of supplemental oxygen and you are experiencing symptoms of hypoxemia and/or low oxygen saturation levels, troubleshoot your oxygen equipment to make sure it is working correctly. It may be advisable to contact your oxygen provider first to ensure that you are checking your equipment correctly, or to get help doing so. If troubleshooting does not resolve your low oxygen levels and you are unable to maintain a normal oxygen level, contact your health care provider. You may need an adjustment in your oxygen dose or your current course of treatment.

Frequently Asked Questions: Low Oxygen Levels 

Are low oxygen levels a medical emergency?

While a low oxygen level, or hypoxemia, is a sign that something is wrong with your breathing or circulation, it is not always an emergency. When you experience a lack of oxygen in the body, symptoms will vary depending on the severity of your hypoxemia. Depending on your symptoms, and your overall health, you will need to take some kind of action to alleviate the low oxygen levels. This could include doing some breathing exercises, using supplemental oxygen if you have COPD or another lung disease, using rescue medication if you have asthma or seeking medical attention. If you use supplemental oxygen, you should also check your equipment to ensure that it is working correctly. If you are unsure of the cause of your low oxygen levels, contact your doctor as soon as possible. If you experience severe symptoms like sudden and severe shortness of breath, rapid heartbeat and fluid retention with shortness of breath and cough at high altitudes, cyanosis, incoherence or inability to move or speak normally, call 911.[15] If you suspect you could have COVID-19, call ahead and speak to a medical professional before going to the emergency room.

I’m on home oxygen, so why do I have a low oxygen level?

If you are on home oxygen, your doctor will prescribe the flow rate and amount of time they determine will provide a therapeutic amount of oxygen for you. Your doctor should indicate the correct oxygen levels for you throughout the day, though depending on your overall health, your levels may still be lower than what is typically healthy for most people. However, if your oxygen levels dip below what your doctor tells you your levels should be, you may need to make some adjustments. Make note of when your oxygen level goes down, as well as any specific activities or times of day that seem to cause a lower oxygen level. Then, try slowing down somewhat and practicing some breathing exercises when your oxygen levels dip below your normal range. If that does not resolve the lower levels, contact your doctor and your oxygen provider. Your equipment may need to be checked, your prescription may need to be adjusted or you may need to incorporate pulmonary rehabilitation or another treatment for your low oxygen levels.

What is a normal oxygen level?

When you measure your blood oxygen level, you will be measuring your oxygen saturation level. A medical professional will often use an arterial blood gas measurement (ABG for short), while a home oxygen saturation measurement is generally taken with a pulse oximeter (often called pulse ox for short). A doctor may use both. If you have a normal oxygen level, your ABG oxygen levels will typically fall somewhere between 80 and 100 millimeters of mercury. A normal oxygen level, when measured with a pulse ox, is typically between 95 and 100%. An ABG measurement below 80 millimeters of mercury, or a pulse ox below 95%, is considered low oxygen saturation. However, if you have a chronic lung disease, your oxygen levels may be different, so talk to your doctor about what a normal oxygen level is for you. 

What happens when oxygen levels are too low?

Your body needs oxygen to work properly, so if your oxygen levels are too low, your body may not work the way it is supposed to. In addition to difficulty breathing, you can experience confusion, dizziness, chest pain, headache, rapid breathing and a racing heart. If you begin to see blue-tinged nail beds, lips, skin or mucus membranes, that is a sign of cyanosis, which means your blood oxygen levels are dangerously low and could lead to respiratory failure. If you are experiencing shortness of breath and see blue discoloration, seek medical help immediately. 

How can you improve your oxygen levels?

The first and most important thing to do is to make sure that you are not doing anything to impede your body’s ability to absorb oxygen properly. That includes quitting smoking if you are still a smoker, avoiding exposure to secondhand smoke and other lung irritants and ensuring you are following treatment orders from your doctor for any condition that may impact your breathing or oxygen saturation. If you have done all of that and you are still experiencing low oxygen levels, your doctor will likely prescribe supplemental oxygen therapy. Oxygen therapy treatments provide you with a higher percentage of breathable oxygen, improving your oxygen absorption, easing symptoms and raising your oxygen levels. Oxygen therapy is extremely effective and safe when used as directed. Ask your doctor if oxygen therapy can help you maintain a normal oxygen level, and contact Inogen to find out more about how our oxygen therapy products can help you.  

Author: Deborah Leader RN, BSN, PHN



[1] Kent, Brian D, et al. “Hypoxemia in Patients with COPD: Cause, Effects, and Disease Progression.” International Journal of Chronic Obstructive Pulmonary Disease, Dove Medical Press, 14 Mar. 2011, www.ncbi.nlm.nih.gov/pmc/articles/PMC3107696/.

[2] “Adult Non-ICU Care: Monitoring Delirium.” Critical Illness, Brain Dysfunction, and Survivorship (CIBS) Center, Vanderbilt University Medical Center, Accessed 2 July 2020, www.icudelirium.org/medical-professionals/adult-non-icu-care-monitoring-delirium.

[3] “Diagnostic Tests for Euphoria.” Right Diagnosis, Healthgrades, Accessed 2 July 2020, www.rightdiagnosis.com/symptoms/euphoria/tests.htm.

[4] Doyle, Glynda Rees, and Jodie Anita McCutcheon. “5.4 Signs and Symptoms of Hypoxia.” Clinical Procedures for Safer Patient Care, BCcampus, 23 Nov. 2015, opentextbc.ca/clinicalskills/chapter/5-3-causes-of-hypoxemia-2/.

[5] Gotter, Ana. “What Does Shortness of Breath Feel Like?” Healthline, Healthline Media, 21 Apr. 2020, www.healthline.com/health/what-does-shortness-of-breath-feel-like.

[6] Felman, Adam. “Fainting: Causes, Diagnosis, and Treatment.” Medical News Today, MediLexicon International, 9 July 2019, www.medicalnewstoday.com/articles/182524#causes.

[7] Areza-Fegyveres, Renata, et al. “Cognition and Chronic Hypoxia in Pulmonary Diseases.” Dementia & Neuropsychologia, Associação De Neurologia Cognitiva e Do Comportamento, 2010, www.ncbi.nlm.nih.gov/pmc/articles/PMC5619525/.

[8] Leader, Deborah. “An Overview of Hypoxemia.” Verywell Health, Verywell Health, 22 Mar. 2020, www.verywellhealth.com/understanding-hypoxemia-copd-914904.

[9] Fox, W. Christopher, et al. “Acute Hypoxemia Increases Cardiovascular Baroreceptor Sensitivity in Humans.” OUP Academic, Oxford University Press, 1 Sept. 2006, academic.oup.com/ajh/article/19/9/958/146284.

[10] Eldridge, Lynne. “Hypoxia Can Lead to Oxygen Starvation of the Tissues.” Verywell Health, Verywell Health, 27 Sept. 2019, www.verywellhealth.com/hypoxia-types-symptoms-and-causes-2248929.

[11] Leader, Deborah. “Secondary Polycythemia Symptoms and Treatment.” Verywell Health, Verywell Health, 20 Nov. 2019, www.verywellhealth.com/secondary-polycythemia-copd-complications-914682.

[12] Pierson, DJ. “Pulse Oximetry Versus Arterial Blood Gas Specimens in Long-Term Oxygen Therapy.” Lung, U.S. National Library of Medicine, 1990, pubmed.ncbi.nlm.nih.gov/2117192/.

[13] “Clinical Use of Pulse Oximetry. Pocket Reference.” International COPD Coalition, International COPD Coalition, 2010, www.moh.gov.sy/LinkClick.aspx?fileticket=lN1Ta1BTqw0%3D&portalid=0&language=ar-YE.

[14] Pilcher, Janine, and Richard Beasley. “Acute Use of Oxygen Therapy.” Australian Prescriber, NPS MedicineWise, 1 June 2015, www.ncbi.nlm.nih.gov/pmc/articles/PMC4653960/.

[15] “Hypoxemia (Low Blood Oxygen) When to See a Doctor.” Mayo Clinic, Mayo Foundation for Medical Education and Research, 1 Dec. 2018, www.mayoclinic.org/symptoms/hypoxemia/basics/when-to-see-doctor/sym-20050930.

Additional sources

Considine, Julie. “Emergency Assessment of Oxygenation.” Acute Care Testing, Radiometer Medical, Jan. 2007, acutecaretesting.org/en/articles/emergency-assessment-of-oxygenation.

Holland, Kimberly. “Is My Blood Oxygen Level Normal?” Healthline, Healthline Media, Updated 27 Sept. 2019, www.healthline.com/health/normal-blood-oxygen-level#oxygen-levels.

“Peripheral Cyanosis: Symptoms, Causes, and Treatments.” Healthline, Healthline Media, 18 Sept. 2019, www.healthline.com/health/peripheral-cyanosis#causes.

Silva, Joana Cavaco. “Low and Normal Blood Oxygen Levels: What to Know.” Medical News Today, MediLexicon International, 28 Jan. 2020, www.medicalnewstoday.com/articles/321044.



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