Oxygen Saturation: Normal Oxygen Level & Shortness of Breath

oxygen saturation, normal oxygen level, normal oxygen saturation

Oxygen Saturation, Normal Oxygen Level, and Shortness of Breath

One of the most frequently asked questions about lung disease is also one of the most baffling: why do people with COPD experience shortness of breath despite a normal oxygen level reading? What is normal oxygen saturation? Because COPD seldom exists in a vacuum, we must look beyond the lungs to find the answer.

COPD and Chronic Heart Failure

According to the American College of Cardiology, heart failure and COPD are common long-term health conditions that frequently co-exist. When you have both conditions, it’s often difficult to differentiate which is causing your symptoms.   Because symptoms of both illnesses commonly overlap – and both frequently occur together – it’s important for people with COPD who experience breathlessness with exertion, coughing during the night, or breathlessness and coughing spells during the night, to undergo a thorough physical examination to determine if the symptoms are related to COPD, heart failure, or both.1

What is Heart Failure?

Heart failure occurs when the heart is no longer able to pump a sufficient amount of blood through the body. Similar to COPD, people with heart failure can be somewhat stable, or they can experience exacerbations (periods of time when their symptoms worsen). There are many conditions that can lead to heart failure, the most predominant being coronary artery disease.

When the heart is too weak to pump enough blood to the cells, tissues, and organs, every system in the body is affected: muscles weaken, weight loss occurs, fatigue and breathlessness are common, and physical activity becomes increasingly difficult.1

How Does Heart Failure affect Oxygen Saturation?

Oxygen saturation is a term used to define how much oxygen your blood is carrying. It is commonly measured by a pulse oximetry monitor, a non-invasive device that attaches to the end of your finger. When people with stable COPD (meaning they are not having an exacerbation) also have heart failure, it’s not unusual for them to experience shortness of breath, yet have a normal oxygen level reading. This is because, as the volume of blood pumped by the heart lessens, the oxygen saturation level isn’t immediately affected. Over time, lack of oxygen affects every organ in the body including the lungs, which may eventually lower oxygen saturation.1

Skeletal Muscle Abnormalities

Rising from bed – getting dressed – taking a shower – going to work – we rely upon our skeletal muscles to perform all our daily activities. Skeletal muscles are found throughout the body. Their primary role is that of supporting the skeleton and voluntarily moving the bones. When our muscles are fit and well-conditioned, daily activities are a breeze; when our muscles fatigue easily from prolonged disuse, daily activities are far more challenging.

Although COPD primarily affects the lungs, skeletal muscle abnormalities are a secondary consequence of the disease. Shortness of breath and fatigue, common symptoms of COPD, often cause patients to limit their physical activity for fear of worsening breathlessness. The vicious cycle of prolonged inactivity, fatigue, and increased breathlessness with exertion leads to decreased muscle fitness and weakness. Remaining immobile for long periods of time causes the skeletal muscles to slowly decrease in size and eventually atrophy, or waste away.2

How Do Skeletal Muscle Abnormalities affect Oxygen Saturation? 

When your muscles are called upon to perform any type of physical task, they have to work harder, which increases their demand for oxygen; this is why exerting yourself increases your heart rate and breathing.  In contrast, calling upon weak muscles to perform physical activity requires much more effort, leading to greater fatigue and breathlessness, more so than if your muscles were fit. Take, for example, climbing 3 flights of stairs; even if you’re moderately active, you’re likely to experience some degree of breathlessness by the time you reach the top. Now imagine your muscles are extremely weak from inactivity; simply rising from a chair or walking across a room can lead to breathlessness.

Unlike shortness of breath directly related to lung impairment however, breathlessness caused by skeletal muscle abnormalities may not always correlate with oxygen saturation. This means it’s entirely possible to experience breathlessness, without seeing a drop in your oxygen saturation level.3

Exercise: The Key to Breathlessness

The answer to breathlessness from COPD, heart failure, and/or skeletal muscle dysfunction is exercise. In fact, the American College of Cardiology reports that people who have COPD and heart failure together are prime candidates for exercise training. What’s more, skeletal muscle abnormalities can be completely reversed by participating in an exercise training program or a cardiopulmonary rehabilitation program.3

Talk to your health care provider for more information about enrolling in cardiopulmonary rehab. If you’re ready to start an exercise program on your own, don’t miss reading: 11 Tips for Exercising with a Chronic Health Condition.


Author: Deborah Leader RN, BSN, PHN

1Jelic, Sanja MD, Le Jemtel, Thierry H. MD. Diagnostic Usefulness of B-Type Natriuretic Peptide and Functional Consequences of Muscle Alterations in COPD and Chronic Heart Failure. CHEST 2006; 130;1220-1230. DOI 10.1378/chest.130.4.1220.
2Sunita Mathur, Dina Brooks, and Celso R. F. Carvalho. Structural alterations of skeletal muscle in COPD. Front Physiol. 2014; 5: 104. Published online Mar 19, 2014. doi: 10.3389/fphys.2014.00104.
3Jelic, Sanja MD, Le Jemtel, Thierry H. MD. Diagnostic Usefulness of B-Type Natriuretic Peptide and Functional Consequences of Muscle Alterations in COPD and Chronic Heart Failure. CHEST 2006; 130;1220-1230. DOI 10.1378/chest.130.4.1220.


15 thoughts on “Oxygen Saturation: Normal Oxygen Level & Shortness of Breath”

  1. carol m carroll says:

    Now I know what is causing my problem. Out of breathe with a normal oxygen level.

  2. Sue says:

    Very Informative answered a lot of my questions Thanks.

  3. praveen Mandha says:

    very informative. Thanks very much

  4. James says:

    Much of the breathlessness is due to hyperventilation – good report.



      1. Inogen Inogen says:

        Hi Charlene, For more information on how COPD patients can avoid hyperventilating, please visit our blog post: http://www.inogen.com/blog/copd-patients-avoid-hyperventilating/

  5. Cathy Hildreth says:

    good information I have DDD as well as lung damage due to a serious chemical spill at a summer job when I was just 28 now at 66 finding out at 50 that I had 50% lung damage but no lung disease. all doctors treatments were for lung diseases giving me all the inhalers and treatments for lung disease, ending up with a bad case of total body osteoporosis, arthritis too. Yet when I took Morphine I could breathe better and walk. due to the DEA going after chronic pain patients scarring off all doctors who prescribe Opiate Therapy with 25 yrs. to life which one doctor here in KS which was reversed in a higher court. However now I am a shut in and without care for my illness and I am racked in pain. I do have an oxygen machine which I use most of my day and night only allowing a few hours a day to let my lungs work themselves using the breathing exercises as well as breathing via my nose as I go to the kitchen barefooted.
    I also am PTSD: yet treatment as a bipolar personality. I am so tired of ignorant doctors who do not understand my conditions. I just gave up and lay in my bed and wonder how long this is going to last

    1. Carole-Jayne Watson says:

      Cathy, I can in no way help you, but I want you to know how sad I am that you are in this situation. It must be terrible and I wish I could help. I am so sorry, I wish you all the best and hope things improve for you.

  6. Linda says:

    Awesome information! I thought my DH was crazy but now I am going to call his Cardiologist!

  7. Linda Stephens says:

    Thank you! This helped me immensely. I had my DH take slow deep breaths and it stopped his panic attack and shortness of breath.

    Also, he is now willing to try going back to his Physical Therapy!

    Greatly informative blog!

  8. Janet Baker says:

    I want to point out perhaps the main point of the article. It distinguishes plain old 'exercise' from strength training, which is different. If you go to cardiac rehab, as I did, they address cardio exercise (basically on a treadmill) and a few minutes wrap up of weights for arms. The strength workout is not part of the exit interview wrap up, and it's easy to lose sight of the strength training necessity and concentrate on the cardio in the workout. When I discussed exercise with my cardiologist, one of the finest in the city, he talked about walking three miles a day and nothing about strength training. I had increasing breathlessness even though the doc assured me that I had 100% heart function, and two weeks ago had a second heart attack with the subsequent placement of two stents and a consequent stroke (from plaque breaking off during the procedure) and during the recovery from the stroke I saw how weak I had become from not addressing the need for strength training. I don't know if it was the cause of my breathlessness but it sure interfered with my recovery. I am adding it back in as soon as they clear me to exercise.

    1. Web Admin Web Admin says:

      Hi Janet, Thank you for your incredible insight. We wish you the best and hope you have a speedy recovery!

  9. Mitsu says:

    Thanks for the informative response to our " out of breath" condition after very little movement.

  10. Stella says:

    I too have a compromised heart from a thyroid storm in my 30's. It didn't show up until I went into high altitude and went into heart failure big time when on vacation in my 60's, which brought all this to a head. I'm sure that as I grew older and had an office job, I lost muscle and became weaker which added to my weak heart. My EF got as low as 18%. With proper nutrition, muscle strengthening , exercise and loosing weight I have improved the EF to up in the 40% range. I also have developed Emphysema. I'm on oxygen 24/7 if I have to be moving. I can set or sleep with out it but that's the only time. And by night time when I'm tired any activity even with oxygen is much worse, it will get down in the low 70's.

    1. Inogen Inogen says:

      Hi Stella, Thank you for sharing your story. Exercising is one of the best ways to stay healthy. For more information on how to exercise with your Inogen One Oxygen Concentrator please visit: http://www.inogen.com/blog/3-easiest-exercises-to-do-with-your-inogen-one-oxygen-concentrator/

Leave a Reply

Your email address will not be published. Required fields are marked *

HTML is not allowed in comments. It is automatically filtered out of comments.

Inogen Call For Support View Cart
Request a FREE Info Kit