An exercise program that increases COPD patients’ ability to perform physical activity with a lessened sensation of dyspnea is a primary goal of rehabilitation.


As we age, we experience sarcopenia, the loss of muscle mass, with an associated loss of muscle strength. There may be additional loss of neuronal function, as well as muscle apoptosis (cell death). Skeletal muscle cell fiber size decreases (atrophy) as a result of numerous factors, including decreased physical activity, bed rest, a reduction in cell growth factors, inflammatory changes, and immunologic factors. When combined with a superimposed chronic inflammatory disease such as chronic obstructive pulmonary disease (COPD), the loss of function may be accelerated—particularly if appropriate countermeasures are not instituted.1

Dyspnea, Fatigue, and Inactivity

Patients with COPD suffer from increased dyspnea, fatigue, impairment of muscle function, reduced exercise tolerance, and compromised activities of daily living.2 As COPD progresses, superimposed acute exacerbations can accelerate loss of strength and functional degradation, which leads to further dyspnea when they try to exert.3 Patients cope with this ever-present disease burden by avoiding exertion and averting unpleasant dyspnea. Consequently, they assume a very sedentary lifestyle. This results in deconditioning, which imposes increased dyspnea from lower levels of exertion.4

Nutritional status can be compromised in the severely dyspneic patient for whom there is a competition between eating and breathing. Lack of nutrition adds yet another burden to an already compromised physiologic profile.5 Collectively, these changes conspire to impose even more limitations on ventilation and pulmonary gas exchange. The result is impairment of peripheral muscle function, cardiac dynamics, nutritional and psychological status, and a host of other physiologic changes and COPD comorbidities.

If the patient continues to smoke or be exposed to environmental tobacco smoke, the foregoing deterioration in function becomes further accelerated.1 An integral component of this chronic and progressive deterioration is the tendency for anxiety, depression, and fear of becoming dyspneic. These, along with an ever-increasing pharmacologic burden, can impose significant challenges for the patient and care team.6,7

Patients with COPD tend to be less active as compared with age and gender matched healthy individuals.8-10 As the level of airway obstruction progresses and exercise hyperinflation occurs, dyspnea increases and physical activity diminishes.2,11-12 Physical inactivity has been shown to be an important prognostic indicator for morbidity and mortality in COPD patients.13-14 Thus, a rehabilitation program that increases the ability to perform physical activity with a lessened sensation of dyspnea is a primary goal of rehabilitation of the COPD patient.

Carter-table1-600

A consistent finding following exercise rehabilitation in patients with COPD is that static pulmonary function tests remain virtually unchanged even though significant gains in exercise ability are achieved.15-18 We now recognize that the COPD burden has imposed specific changes to numerous physiologic systems and these are amenable to a training response at all levels of airway obstruction and COPD progression. It is well established that COPD is characterized by flow limitation and impairment in gas exchange.19 This heightens the sensation to dyspnea and promotes physical inactivity. As inactivity continues year-to-year, skeletal muscle function declines, as does cardiac function and the efficiency of all interrelated physiologic systems to respond to exercise stress is compromised.20 The process is perhaps more gradual than immediate bed rest or placing an individual at zero gravity, but the end results are similar except these individuals do not possess irreversible airway damage and impaired gas exchange.21-22

Fortunately, there are opportunities for reversing some of the functional decline experienced by COPD patients through participation in exercise programming. The American College of Sports Medicine advocates that all exercise programs be comprised of exercise intensity, duration, frequency, and mode of exercise tailored in an individualized manner based on need, interest, and special concerns.23 While specific guidelines have been devised for healthy, disease-free individuals, the exact prescription for exercise intensity and duration are less well established for COPD patients.

There is a consensus that optimization of physiologic function should be a key ingredient to promoting maximal benefits derived through the training response. Thus, respiratory medicines—particularly bronchodilators—should be optimized and taken prior to the exercise session so as to maximize airway function and therefore improve exercise capacity. Further, breathing strategies should be taught and used as part of the program to control dyspnea and enhance exercise participation. Some investigators suggest that exercising the respiratory muscles may be included in addition to whole body exercise for enhancing overall function and lessening dyspnea.24-26

Lastly, there do not appear to be any specific pulmonary function inclusion criteria for admission to a rehabilitation program since symptoms and functional limitations determine the need for rehabilitation. Patients with mild through severe airflow limitation have improved outcomes following rehabilitative efforts. However, while pulmonary rehabilitation is often advocated for those in the later stages of the disease, those with early disease may benefit even more and the disease trajectory may be altered in a favorable manner if early intervention is initiated and incorporated into their lifestyle over the long-term.

Breathing Strategies and Exercise Training

Breathing techniques are often incorporated in pulmonary rehabilitation to reduce dyspnea and lessen the work-of-breathing. Techniques commonly employed include diaphragmatic breathing and pursed-lip breathing.

In addition, patients who are hypoxemic at rest will likely require oxygen during exercise conditions. Patients who are hypoxemic during exertion will definitely require oxygen during exercise conditioning. There is no benefit for patients to exercise while depriving themselves of this essential molecule. Some studies have shown a benefit of exercise training with supplemental oxygen even if they are nonhypoxemic during moderate exercise. They are able to exercise longer with less dyspnea.27

Diaphragmatic Breathing

This technique is often used in rehabilitation of patients with chronic lung disease or asthma, where the use of the diaphragm and external intercostals (primary muscles of inspiration) needs to be emphasized while the use of accessory muscles needs to be discouraged.28 The principle behind diaphragmatic breathing is enhancement of the diaphragmatic descent during inspiration and ascent during expiration. Efficiency of diaphragm and respiratory pump is suggested resulting from the elimination of unwanted movements of the upper rib cage that are known to occur in patients with COPD.29-30 In learning this technique, the patient becomes conscious of their breathing pattern as related to their experienced dyspnea and thus better manages their level of distress with a learned breathing strategy.

Diaphragmatic breathing is typically taught with the patient positioned on their side lying on a bed in semi-Fowler’s position with bent knees and hips, to achieve relaxation of abdominals and hamstrings. The patient’s dominant hand is placed over the mid-rectus abdominis area and the other hand on his chest. The descent of the diaphragm during inspiration is achieved by asking the patient to protract the abdomen during inhalation, and the dominant hand rises as inhalation continues. Conversely, the patient retracts the abdomen during expiration, which causes the ascent of the diaphragm.

At first, the therapist may assist the patient by giving a firm pressure on the dominant hand just before the inhalation. Later, the patient’s hand is used to feel the ventilatory pattern. This breathing technique is progressed from side-lying position to supine, sitting, standing, walking, and finally stair climbing. Diaphragmatic breathing has been associated with the improvement of blood gases, pulmonary mechanics, and dyspnea in severe hypercapnic COPD patients.31

Pursed-lip Breathing

Pursed-lip breathing (PLB) is one of the breathing retraining strategies used to control dyspnea in COPD patients.32 Some patients with dyspnea naturally incorporate this type of breathing pattern while some have to be taught. In a PLB maneuver, the patient is asked to sit in a comfortable position, inhale slowly through the nose, and then relax the air out through pursed lips. Any abdominal muscle activity during exhalation should be avoided and this can be detected by placing the therapist’s hand over the mid-rectus abdominis area of the patient. The breathing training can be progressed by replacing the therapist’s hand with the patient’s, and performing the technique while standing and exercising.

The slight resistance to expiration, provided during PLB, increases the positive pressure within the airways, which keeps open the smaller bronchioles, thus improving efficiency of ventilation.33 It is evident that PLB also helps to improve gas exchange,34 alveolar ventilation, and oxygenation,33-35 and reduces dyspnea.34 These effects have been attributed to the decrease in respiratory rate and increase in tidal volume resulting from PLB.36 Breslin34 also observed a change in the pattern of chest wall muscle recruitment along with improved SaO2 post PLB in patients with COPD. It was hypothesized that these improvements resulted in less diaphragmatic muscle fatigue during breathing. The oximeter can be utilized as a biofeedback guide to increasing SpO2.37

Resting the Respiratory Muscles

Dyspnea in COPD patients often results from chronic fatigue of the respiratory muscles.38-39 This has influenced some investigators to speculate that resting the respiratory muscles would help alleviate fatigue and thus improve function.40 The respiratory muscles can be rested using positive or negative pressure ventilation and several studies reported improvement in ventilation and respiratory muscle strength after negative pressure ventilation using an iron lung.41 Numerous ventilator devices also are used to provide respiratory muscle rest. These include noninvasive nasal ventilator support systems like CPAP and BiPAP, which are used to provide a positive airway pressure to patients experiencing respiratory failure and/or sleep apnea.40,42-43

Whole Body Exercise Programming

Guidelines for pulmonary rehabilitation exercise prescription have been published by major leading organizations to provide quality evidence-based rehabilitative methods. According to the recent guidelines: The goal of pulmonary rehabilitation exercise is to improve exercise tolerance and also promote increased participation in activities of daily living.1-3

The key components for exercise programming include intensity, duration, frequency, and mode of exercise. Special attention to exercise progression and specificity of training must be considered to yield the most beneficial outcomes.44 Establishing the optimal intensity for exercise training is the most perplexing component for individual patients. Exercise intensity should be greater than what will be normally experienced in everyday life for exercise to achieve its greatest benefit. For patients with COPD, this means going to an uncomfortable level of breathing where the breathing strategies outlined above can be used to control dyspnea and increase exercise intensity.

Initially, patients will want to start with light intensities until they are capable of 30 to 45 minutes (duration of exercise) of exercise daily, even if divided into several sessions.45 Recent research has shown that higher intensities yield greater gains in performance, with less dyspnea.46-47 At the minimum, 3 days of structured exercise should be completed per week (frequency of exercise).

More days of training are also advocated and can be accomplished in the home setting, even if the intensity of training is decreased. This concept goes to the total dose of exercise accomplished per week and is important for establishing and maintaining exercise practices long-term. Additionally, the therapist must explore various modes to exercise and attempt to select modes that the patient likes, and those that can be adhered to outside of the clinic setting. This will encourage long-term adherence to the exercise program. Research suggests that interval training is an appropriate approach for exercise that is equally as effective as steady state training.48-49

Endurance training has traditionally been advocated as the primary approach to training, yet it is not an optimal approach for increasing muscle mass, strength, and power, which are also beneficial in patients with COPD.48-50 To counter the ill effects of chronic muscle wasting, reduce the likelihood of catastrophic falls, and improve muscle tone and function, strength-training techniques should be part of the overall prescription.

For strength training to be effective, the principle of “overload” should be applied.23 Overload is the gradual increase of stress applied to the body (muscle groups) during exercise. As the body adjusts to a given level of stress, the activity becomes easier to perform and typically occurs with less dyspnea. In order for the training effect to be extended, additional stress must be applied (eg, increased intensity) to the training program and a new limit of exercise will be established. From a physiologic perspective, application of overload will result in physiologic adjustments through improved efficiency and adaptation to the exercise.

For patients with COPD, the choice of how to apply the overload differs from patient to patient and should be individualized based on need and limitations. Common strategies for delivering resistance to specific muscle groups include using items common to the home as light resistance instruments (eg, cans of food), to surgical tubing and resistance bands, to weight machines and free weights. With common activities of daily living requiring the use of the upper and lower body musculature, it is appropriate to utilize strength training to improve tolerance to such activities when limitations are present.48-50

Patients with COPD have great difficulty performing overhead arm movements while controlling dyspnea, thus this should be an area of focus with light weights and repetitive movement.51 Further, breathing strategies should be used to control dyspnea while avoiding Valsalva maneuvers during exercise. Present guidelines for strength training suggest performing one to four sets of eight to 15 repetitions each, at intensity between 60% and 70% of the patient’s one repetition max.44,48-49

If the patient is just starting a program, the use of light resistance is encouraged to learn movement patterns while concentrating on breathing strategies for dyspnea control during the first week or two. When the patient is capable of performing several sets of 15 reps each, the resistance can be increased and the number of reps decreased. With continued training, the number of reps will again return to the 15-rep level and once again the resistance can be increased. The BTS specifically states that strength training should be individualized for each patient.3 Again, it is important to assure that the patient is adequately oxygenated during exercise training.

Summary

All patients with COPD can benefit from exercise programming following optimization of medications, oxygenation, physiologic status, and nutrition. In this context, exercise is the best long-term approach to reducing dyspnea of exertion. While the outcomes may vary from patient to patient, restoration of functional loss is a high priority and this should translate to improved activities of daily living and a reduction in dyspnea.

High-intensity exercise, at or above the anaerobic threshold, has demonstrated efficacy. Less strenuous exercise regimes are effective and can impart significant functional improvements. In approaching exercise for specific patients, a needs assessment should be completed noting the patient’s likes and dislikes with regard to exercise. This may go far in ensuring a long-term continuing benefit of exercise training. A thorough medical and physiologic review should take place and then an individualized program for rehabilitation prescribed. Because exercise is dose-dependent, all patients should be encouraged to exercise outside of the clinic. Lastly, the rehabilitation process should be part of the overall disease management for the patient with COPD. RT


Rick Carter, PhD, MBA, Lakshmi Manasa Munuganti, BS, PT, and Allen Sexton, BS, work in the Department of Exercise Sciences at Lamar University, Beaumont, Tex. Brian Tiep, MD, is a physician at City of Hope National Medical Center, Duarte, Calif. For more information, contact editor@RTmagazine.com.


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