This is an excerpt from Guidelines for Pulmonary Rehabilitation Programs-4th Edition by AACVPR.
Exercise training in pulmonary rehabilitation should encompass both upper- and lower-extremity endurance training, strength training, and possibly respiratory muscle training. Duration, frequency, mode, and intensity of exercise should be included in the patient's individualized exercise prescription, based on disease severity, degree of conditioning, functional evaluation, and initial exercise test data. Various guidelines for exercise training have been suggested. (3-4) Aerobic endurance training may be performed at high or low intensity. (44-45)
High-intensity training of 60 to 80% of peak work rate must be undertaken to gain maximal physiological improvements in aerobic fitness such as increased .V O2max, delayed anaerobic threshold, decreased HR for a given work rate, increased oxidative enzyme capacity, and capillarization of muscle. (39,44-45,62,67) These physiological changes result in a lower ventilatory requirement for a given exercise task as well as a more efficient pattern of breathing, with reduced dead space ventilation due to increased tidal volume and decreased respiratory rate. High-intensity training is associated with substantial gains in exercise endurance. (44)
Not all patients can tolerate sustained high-intensity exercise at the outset of training. However, those patients working at their maximal tolerated exercise level will achieve gains over time. (62) Interval training, alternating periods of high and low intensity (or rest), is an effective training option for persons who cannot sustain extended continuous periods of higher-intensity exercise. (63-65)
Traditional physiological changes associated with aerobic fitness from high-intensity training are not required to improve exercise tolerance and function in many patients with chronic lung disease. This is important because the unpleasant dyspnea and leg fatigue associated with high-intensity exercise may interfere with its incorporation into patients' daily lives. Moreover, it has not been proven conclusively that high-intensity exercise, with achievement of physiological gains in aerobic fitness, leads to greater improvement in day-to-day functional activity. Lower-intensity aerobic exercise training leads to significant improvements in exercise endurance, even in the absence of measured gains in aerobic fitness. (9,66) Lower-intensity
training may be more readily incorporated into the patients' daily activities, although this has not been demonstrated in clinical trials.
Transcutaneous neuromuscular electrical stimulation can improve lower-extremity muscle strength and exercise endurance even in the absence of traditional cardiovascular exercise training. (68-70) Although no large trials are available, this may be an option for patients with very severe diseases who are unable to participate in a conventional exercise training program.
Frequency and Duration of Exercise
In general, the frequency and duration of the supervised exercise component during a pulmonary rehabilitation program may vary from three to five times per week (2-3,35-37,39,41,44), 20 to 90 minutes per session (3,40-41,43), and extend over a period of 4 to 12 weeks (2,4,11-12,42-43). If program constraints will not allow for supervised exercise at least 3 days per week, one or more unsupervised sessions per week, in the home, with specific guidelines and instruction, may be an alternative option. However, it remains to be determined if this approach is as effective. (3,37) If the patient is very debilitated, the duration of the initial exercise sessions can be shorter with more frequent rest breaks; however, the ultimate goal is to achieve fewer or no rest breaks and at least 30 minutes of endurance exercise within the first few weeks of rehabilitation. An example of achieving 30 minutes of endurance exercise with a very debilitated patient is given in figure 4.8.