Chronic obstructive pulmonary disease, or COPD, blocks the airways of the lungs, causing shortness of breath. Research shows that exercise can help people who suffer from COPD, so it’s a good idea for fitness professionals to understand the disease (ALA 2011).
COPD is the third leading cause of death in the United States: Approximately 12 million people are diagnosed with this incurable disease, and an estimated 12 million more may have it and not know it (NHLBI 2013). Chronic bronchitis and emphysema are the two major forms of COPD.
- Chronic bronchitis is a long-term inflammation or swelling of the bronchi (air passageways) in the lungs, causing a buildup of mucus or phlegm from the bronchial tubes (see Figure 1). Sufferers develop a nagging cough and a frequent need to clear the throat of mucus secretion.
- Emphysema is the long-term destruction of the alveoli (air sacs) of the lungs (see Figure 1), causing progressive shortness of breath from inefficient exchanges of oxygen and carbon dioxide in the blood. Smoking is the primary risk factor for COPD, but people exposed to certain gases or fumes, large amounts of pollution or secondhand smoke are also at risk.
COPD is usually preventable, with one notable exception. Approximately 100,000 Americans have alpha1 antitripsin deficiency-related (AAT) emphysema, an autoimmune disease characterized by a deficiency of the liver protein AAT, which promotes healing of lung tissue as cells age and/or become damaged (ALA 2011). AAT emphysema is inherited and cannot be prevented. A blood screening is needed to detect an AAT deficiency.
People with COPD have trouble exercising because diminished airflow makes them short of breath. Nevertheless, progressive exercise should be encouraged, as it offers many health benefits for COPD clients.
Pathophysiology of COPD
Excessive secretions of mucus and airway inflammation are two prominent symptoms of COPD (Rodríguez-Roisin 2005). Thickening of the bronchial tube lining will decrease the diameter of bronchial airways and increase the resistance to airflow, causing breathing difficulties. Inflammation of this lining will further decrease the diameter of the airways, thus impairing the amount of air transported. McDonough et al. (2011) determined that the number of small airways and terminal bronchioles (smallest passageways in bronchial tubes) decreases as COPD progresses.
Emphysema is long-term damage to/destruction of the alveoli, which allow life-giving gas exchanges: Oxygen from the lungs is transferred to the blood, while carbon dioxide in the blood is sent to the lungs for release. As emphysema progresses, more and more alveoli are wiped out, limiting these gas exchanges. This makes the extraction of oxygen from the lungs more difficult; an individual who suffers from emphysema will continuously feel short of breath.
The cause of the alveoli’s destruction is under investigation. Some research suggests that changes in elastin, a protein providing elasticity in alveoli, may cause the alveoli to lose their physiological function (Lang et al. 1994). Other evidence identifies fibrosis—thickening and scarring—of the alveoli as the cause of emphysema (Lang et al. 1994). This fibrosis of the alveolar walls may be a consequence of inhaling smoke, gases and fumes.
Exercise and COPD
Exercise has several benefits for people with COPD. A recent study determined that cardiovascular exercise increased levels of the vital protein PGC-1α in COPD sufferers, and the increase was greater in those who exercised above their lactate threshold than in those who exercised below it (Puente-Maestu et al. 2011). PGC-1α is a cellular protein that increases the number and function of mitochondria, the energy powerhouses of cells, leading to greater exercise endurance. This explains why regular endurance exercise can help people with COPD improve their functional endurance capacity and their quality of life (Probst et al. 2011).
Additionally, aerobic exercise has been shown to improve the plasma metabolic profile of individuals with COPD. Rodríguez et al. (2012) determined that COPD patients had markedly lower levels of certain amino acids circulating prior to exercise, pointing to possible systemic side effects of the disease, including abnormal muscle bioenergetics (that is, an increase in anaerobic metabolism and a decrease in oxidative metabolism, versus a decrease in anaerobic metabolism and an increase in oxidative metabolism, as seen in healthy people). The authors concluded that exercise improved the functions of these energy systems and would benefit most COPD patients.
The American Lung Association suggests that exercise programs include stretching, aerobic exercise and strengthening/resistance exercise to build up respiratory muscles, enhance circulation and improve COPD symptoms. Stretching the upper body helps maintain and improve the elasticity of the respiratory muscles. Aerobic exercise improves blood and oxygen circulation, reduces blood pressure and strengthens the heart and cardiovascular system. Total-body strengthening/resistance training is encouraged because it engages and improves the musculoskeletal system’s ability to handle the load challenges of daily living.
Because symptoms vary considerably in those with COPD, exercise professionals should design individualized programs based on guidelines from the American College of Sports Medicine:
- Complete 150 minutes of moderate-intensity (somewhat hard) exercise throughout the course of the week.
- Resistance-train each major muscle group 2 or 3 days each week, using a variety of exercises.
- Do flexibility exercises at least 2 or 3 days each week to improve range of motion (ACSM 2011).
Personal trainers should focus on increasing the duration and intensity of exercise gradually, as shortness of breath will initially impede the exercise workout for a client with COPD.
Also, while higher-intensity aerobic exercise can help some people who have COPD, high-intensity exercise may cause oxidative stress (i.e., release of free radicals) in some blood vessels. This stress may in turn cause more damage to the already inefficient airways in the lungs. Therefore, exercise programs incorporating high-intensity interval training should be approached with caution, depending on the client’s health status.