It’s well known that COPD (chronic obstructive pulmonary disease) causes difficulty breathing. But can it also cause muscle weakness?
Studies indicate that there is a connection. But there is some disagreement on whether COPD itself causes muscles to weaken; other factors may play an important role.
COPD affects ventilatory muscles—your rib cage, diaphragm, and abdominal muscles—as well as skeletal muscles, which allow you to perform a broad range of movements.
Lesley Williams, Apria’s Market Clinical Trainer and a registered respiratory therapist, says, “People with COPD often complain of fatigue and weakness in their legs and arms, making walking or carrying items difficult. And about 40% suffer from exercise intolerance, which contributes to muscle weakness.”
This article is designed to enhance your understanding of the causes of muscle weakness as well as strategies to help you strengthen your muscles and improve your quality of life.
There are a variety of factors that lead to muscle weakness. And some people may have more than one. Following are leading causes:
It’s natural: as you grow older, your muscles generally get weaker.
The degree of muscle weakness is often related to the severity of your COPD. For example, muscle deterioration (also called muscular atrophy) tends to be more severe in people with emphysema.
Hypoxia is a condition where you have low levels of oxygen in your tissues. People with COPD often get hypoxia since they have difficulty breathing, which makes it harder to deliver oxygen throughout their body. Chronic hypoxia has been shown to cause muscle wasting and weakness.
When your airways are obstructed, breathing is harder, leading to exercise intolerance. As a result, muscles get weaker from lack of use.
This happens when too much air gets trapped inside your lungs. When you can’t exhale properly, breathing becomes harder.
Hyperinflation can also lead to changes in the shape of your chest wall (called chest wall remodeling). Combined, they contribute to shortness of breath (dyspnea) and an increased risk of exercise intolerance.
This is a condition where you have an imbalance of free radicals—unstable atoms that can cause cell damage and other illnesses—and antioxidants, which protect your cells from free radicals. This imbalance can lead to oxidative stress, which can cause your muscles to weaken.
You are more likely to have weaker muscles if you have COPD in addition to another condition, such as cancer, diabetes, or heart disease.
Leptin is a hormone that helps regulate your appetite. People with COPD often have elevated levels of leptin, which decrease their appetite, leading to weight loss and loss of muscle mass.
People with COPD are less active than others, especially during periods of flare-ups. Muscle disuse can result in muscle loss.
People with COPD often have systemic inflammation—inflammation that happens throughout the body or at specific locations. This can affect muscle strength and cause fatigue.
Researchers believe that chronic hypoxia and corticosteroid therapy, which doctors may prescribe to treat inflammation, cause lower testosterone levels and contribute to muscle weakness.
Taking a daily walk is one of the best—and easiest—exercises you can do to help increase your muscle strength, especially in your legs. Riding a bike or dancing are also recommended.
Speak with your doctor about pulmonary rehab (also called PR), where you’ll learn about breathing exercises, other forms of exercise, and nutrition to help to improve lung endurance, exercise capacity, and muscle strength.
Research shows that even moderate exercise strengthens respiratory muscles and makes breathing easier. Exercise also helps you maintain a healthy weight and strong muscles.
Work with your doctor to determine the type and amount of exercise that’s right for you.
Proper nutrition is key to your overall health. Try eating smaller meals throughout the day. This increases your calorie intake, which helps build muscle mass.
Supplemental oxygen reduces dyspnea while also increasing your exercise capacity.
Don’t let COPD sap your strength. Apria’s Lesley Williams advises, “Use the strategies outlined in this article to help increase your muscle mass so you can perform your normal daily activities—and enhance your overall health and well-being.”
References
1. Wüst RC, Degens H. Factors contributing to muscle wasting and dysfunction in COPD patients. Int J Chron Obstruct Pulmon Dis. 2007;2(3):289-300.
2. Jaitovich A, Barreiro E. Skeletal Muscle Dysfunction in Chronic Obstructive Pulmonary Disease. What We Know and Can Do for Our Patients. Am J Respir Crit Care Med. 2018 Jul 15;198(2):175-186.
3. Mathur S, Brooks D, Carvalho CR. Structural alterations of skeletal muscle in copd. Front Physiol. 2014 Mar 19;5:104.
4. Clifton, T. (2022, August 1). Can COPD Cause Muscle Weakness? Healthline. https://www.healthline.com/health/copd-muscle-weakness.
5. Canter, J. (2021, November 3). COPD Complications and Other Conditions. WebMD. https://www.webmd.com/lung/copd/copd-complications.
6. Upham, B. (2023, April 15). 7 Signs Your COPD Is Getting Worse.
Everyday Health. https://www.everydayhealth.com/copd/signs-your-copd-getting-worse/.
7. Upham, B. (2018, July 10). 5 Things You Should Know About Exercise if You Have COPD. Everyday Health. https://www.everydayhealth.com/copd/things-you-should-know-about-exercise-you-have-copd/.
8. Geng, C. (Updated 2023, May 31). How and why to exercise when you have COPD. Medical News Today. https://www.medicalnewstoday.com/articles/copd-exercises#how-exercise-helps.
9. Dix, M. (Updated 2018, September 29). Everything You Should Know About Oxidative Stress. Healthline. https://www.healthline.com/health/oxidative-stress.
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