by Jonathon Sullivan MD, PhD, SSC, PBC
Adults with COPD need strength training for all the reasons everybody else needs it--only more so.
COPD, or Chronic Obstructive Pulmonary Disease, has been an important part of my life for a long time. My mother was a lifelong smoker who ultimately became a pulmonary cripple from chronic bronchitis, one of the two major phenotypes of the disease. The sound of her constant wet cough will haunt me to the end of my days.
A career in emergency medicine confronted me with COPD exacerbations and emergencies on a daily basis. These cases were often satisfying to treat, because available therapies can often turn around patients in extremis with respiratory distress and respiratory failure if they come in soon enough. But some cases were nightmares, especially those who had been in distress for a day or more and arrived in the late stage of an exacerbation, after simple airway spasm had progressed to inflammation, swelling, and mucus plugging. These cases frequently went upstairs to the intensive care unit. Or downstairs, to the eternal care unit.
The global burden of COPD is horrific. One third of a billion people suffer from some form of the disease, and the US ranks high on the list of effected countries, with up to 1000 deaths per million persons per year. The most common causes by far are environmental, and smoking is the major individual contributor to the incidence the disease.
Only rarely did I encounter a patient with COPD who had never smoked.
The classical teaching is that COPD comes in two main flavors: emphysema and chronic bronchitis. Emphysematous patients in the late stages of the disease are called "pink puffers," and they tend to be markedly underweight with a high degree of muscle wasting. The "blue bloaters," those with chronic bronchitis, look just like it sounds. In emphysema, lung tissue is virtually dissolved away, resulting in large gaps that are incapable of gas exchange. In chronic bronchitis, chronic inflammation results in secretion of mucus and inflammatory changes that fundamentally alter the elasticity and compliance of airways and literally "plug up" gas-exchanging structures.
Like most classical teachings, this pink puffer/blue bloater distinction is now understood to be simplistic and only somewhat helpful. COPD spans a range of different pathophysiological and clinical phenotypes, but they all result in the same basic problem: obstruction to airflow. Thus, COPD attacks one of the three pillars of clinical physiology:
1. Blood must go round and round,
2. Air must go in and out, and
3. Oxygen is good.
More specifically, COPD has a disproportionate effect on the air getting out, and turns expiration from a passive process to an active process that increases the work of breathing. This means that early COPD primarily effects not oxygenation, but ventilation. Air checks in, but it can't check out. The patient can absorb oxygen, at least at first, but can't get rid of carbon dioxide efficiently. This can become a major problem, ultimately resulting in respiratory acidosis (which is even worse than it sounds), increased work of breathing, and fatigue--what we used to call "pooping out" in the ER.
Pooping out is never good.
Fortunately, the disease is treatable, with bronchodilators, corticosteroids, targeted anti-inflammatories, mucolytics, and smoking cessation, with ventilatory support for severe exacerbations.
Obviously, COPD can have a huge impact on quality of life, and it won't come as a shock to most of you to learn that the majority of patients with the disease are deconditioned, weak, sarcopenic, and sedentary. Common sense might suggest that exercise is out of the question, especially vigorous or intense exercise like heavy resistance training. But you know better, don't you?
There is an abundant and growing body of research on resistance training in the setting of COPD. The first issue that interests us, as always, is safety. Liao et al conducted a 2015 meta-analysis of randomized trials that investigated a combined total of 750 subjects, and found that resistance training could be performed as part of pulmonary rehab without increased adverse events. Skeletal muscle mass and quality of life improved without a significant concomitant increase in exercise tolerance. It must be pointed out that almost all of the incorporated studies were small and short (as usual), and suffered from the usual issues with prescription of clinically effective resistance training.
A systematic review by Iepsen et al, also in 2015, found that strength training seemed to confer the same benefits as endurance training, but the authors were forced to conclude that the quality of evidence they had to work with ranged from moderate to very low quality. Their conclusion seemed to be that strength training vs endurance training was a 6-of-one, half-dozen-of-the-other proposition, which belies a certain disconcerting misapprehension of exercise medicine and exercise physiology.
The same group confirmed their confusion in the summation of another study a year later, which concluded that "Although both ET and RT improve symptoms and exercise capacity, ET induces a more oxidative quadriceps muscle phenotype, counteracting muscle dysfunction in COPD." The flabbergasting and totally incorrect implication here is that older muscle with a greater ratio of high-powered, non-oxidative (non-aerobic) type II fibers--the strong and powerful fibers preferentially lost in aging--is somehow "dysfunctional." Astonishing.
Menon et al conducted an ultrasound assay of muscle mass in 45 COPD patients and 19 healthy controls in the setting of an 8 week program of isolated knee extensions, and found muscle mass improvement--and not incidentally suggested a clinically accessible modality (point-of-care ultrasound) by which doctors might follow improvements in muscle mass in COPD and other patients for whom they prescribe strength training. If they ever did. Which they don't. But more on that later.
One more to nail it home: Kongsgaard et al published a small but important pilot study of 18 patients undergoing a twice-weekly RT program and found that 12 weeks of such training resulted in increased strength, power, muscle size, functional performance and "self reported health."
We're in familiar territory here: we have a powerful form of lifestyle and exercise medicine that can safely improve the health, function, and well-being of patients with an important degenerative disease of modern aging. But this medicine remains poorly studied, in part because it's not a pharmaceutical that promises to make anybody filthy rich. And this powerful medicine is infrequently prescribed, because clinicians aren't familiar with it or hold an antiquated view of the risks and benefits of properly prescribed strength training.
In summary, the large body of data we have on this topic is of middling quality at best, and some of it is ridiculous at worst, but it all points in the same direction: Patients with COPD can safely and productively train and improve their lives.
If you have COPD, you need to quit smoking today. This will start slowing down progression of the disease and improve respiratory function in many sufferers, immediately. You need to use your bronchodilator (proventil, albuterol, et al) as necessary and without hesitation, take your preventives (steroids, PDE-4 inhibitors, etc.) on schedule without fail, and comply with any prescription for pulmonary rehab and pulmonary toilet or oxygen supplementation.
And you need to get exercise. That exercise must include strength training, because, strangely enough, COPD does not protect us from the loss of bone, muscle, strength, and function that afflicts other adults. In fact, the opposite is true: COPD puts adults at higher risk of muscle loss and bone loss than their unafflicted counterparts of equal age.
Adults with COPD need strength training for all the reasons everybody else needs it--only more so.
Jonathon Sullivan MD, PhD, SSC, PBC is a retired emergency physician and research physiologist, and the owner and head coach of the Greysteel Strength and Conditioning Clinic in Farmington Hills, Michigan, which specializes in training adults over 50. He is the author of The Barbell Prescription: Strength Training for Life After Forty, with Coach Andy Baker.