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Breathlessness vs. Oxygen Saturation with COPD: Understanding the Difference

Shortness of breath, or feeling breathless, is what most people think of as the hallmark symptom of COPD. It's certainly one of the most common symptoms, as well as perhaps the scariest. This is true whether you're the person with COPD or the caregiver.

But pulse oximeters, which measure your oxygen saturation levels, have become more popular and accessible over the past decade. Because of that, people with COPD may be relying as much on their oximetry results as their actual symptoms when evaluating their breathing status. And that can cause confusion.

The reason is that you can have "normal" oxygen saturation levels while feeling extremely short of breath. On the other hand, you may not notice any symptoms at all when your oxygen saturation levels dip dangerously low. How is this possible? That's what I hope to clarify in this post.

The difference between being short of breath and being hypoxic

There are three basic factors that affect how well your body is able to take up and use oxygen.1

  • Your lungs' ability to move oxygen into your body and move carbon dioxide out
  • Your heart's ability to pump oxygen throughout your body
  • The ability of your body cells and muscles to actually use the oxygen they get from the blood

Obviously, various disease processes, such as COPD or heart disease, can affect all three of those factors. In fact, COPD's lung damage, along with possible cardiac complications, definitely can impact all three of these. Medication, supplemental oxygen and exercise may result in some improvements.

Feeling breathless

Being short of breath, or breathless, can result from a number of factors. Although this is a frequent symptom of COPD, not everyone who feels short of breath has COPD. Besides lung damage or airway inflammation (such as with asthma), here are a few other factors to be aware of:1,2

  • Heart health
  • How fit you are
  • Emotions
  • Weather
  • Altitude
  • Infection
  • Low red blood cell count (anemia)

It's important to understand, though, that feeling breathless does not always mean that you are hypoxic.

Being hypoxic or having hypoxemia

Hypoxemia means there is a low level of oxygen in the blood. Being hypoxic means that not enough oxygen is getting to your body's cells.3 You can test for these conditions by measuring your oxygen saturation level. There are two ways to measure it:

  • A blood test called arterial blood gases, done by your doctor or a lab tech
  • A small hand-held device called a pulse oximeter that fits over a finger tip. (It uses infrared rays to measure the percentage of oxygen in your blood.)

Oxygen saturation depends on your overall health, how fast you are breathing and your activity.4

Healthy people generally have oxygen saturation levels that range from 95 to 100%. Anything under 90% is considered low and unhealthy. It's not unusual for people who have COPD to dip below 90% at times.

Short of breath, but not hypoxic

How is this possible? I've often seen this question, or related comment, in our community, "How can I be so short of breath, while my oxygen levels are still normal?" Understanding the answer to that is essential in knowing how to proceed. Even if you're extremely breathless, but your oxygen saturation levels remain in a healthy range, then supplemental oxygen is not the answer.1

Instead, it's important to know how to recover from breathlessness. Certainly, resting right away is the first step. Stop whatever you were doing that contributed to you feeling breathless. Respiratory therapist, Mark Mangus, suggests these additional actions:1

  • Remind yourself that you know what to do. Taking action can help you overcome the anxiety that often goes along with being short of breath.
  • Position yourself to breathe easier. Leaning forward or bending over helps drop your abdomen away from your lungs, making breathing easier. Lean your arms on your knees or on some stationary object like the wall or a counter. (I remember often seeing my dad doing this, especially after a severe coughing spell.)
  • Work on controlling your breathing. If you know how to do diaphragmatic or pursed lip breathing, then do so. If you haven't learned those techniques yet, then at least work on slowing and deepening your breaths in and out.

Once you are feeling better and more in control of your breaths, it may be time to resume whatever you had been doing. But you may need to modify the intensity to avoid re-triggering your breathlessness.

Pulmonary rehab can be beneficial in teaching you how to avoid and/or deal with this symptom. In addition, a rescue, or quick-relief, inhaler is sometimes helpful. Talk with your doctor about these options, if you haven't already.

Hypoxic, but not short of breath

It might be hard to understand how your oxygen could be low if you are not feeling at all breathless. But here's the deal--having a low oxygen saturation level is not healthy! And it should not be ignored. Whether your low oxygen levels are measured by a blood test done by a health professional or by a pulse oximeter, pay attention.1

Even an oxygen level just slightly lower than 90% can be serious. It means your blood and tissues are not getting the oxygen they need to survive, and it needs to be addressed right away.

The answer to hypoxia is supplemental oxygen.1 How much and how often you need it is a decision to be made in concert with your health care team. They can also help you with a plan for how often to measure your oxygen levels with a home pulse oximeter.

Work with your doctor for the best plan for you

When you have COPD, shortness of breath (and other symptoms, such as coughing) are an important measure of your current health status. However, knowing your saturation level is also important. And, unfortunately, it is entirely possible to be short of breath, but have healthy oxygen saturation. It is also possible to have unhealthy oxygen saturation levels, without any noticeable symptoms, at least initially.

So, taking a two-pronged approach to understanding your current respiratory status can be helpful. Talk with your doctor to come up with the best plan for you.

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