Chest
Clinical InvestigationsEffect of Respiratory Muscle Endurance Training in Patients With COPD Undergoing Pulmonary Rehabilitatio
Section snippets
Subjects
Thirty-eight consecutive patients with COPD who entered our pulmonary rehabilitation program agreed to participate in the study. Patients were grouped into classes of three to five patients. Each class was randomly assigned to endurance training alone or endurance training plus hyperpneic (combined) training. Nineteen patients were randomized to both the endurance training group and the combined training group. Five patients in the endurance therapy group and three patients in the combined
Pulmonary Function Testing
Spirometry was performed according to American Thoracic Society recommendations.10 Lung volumes were measured by body plethysmography, and single-breath diffusing capacity was also measured. The predicted normal values were those of Crapo and colleagues.11, 12, 13 Maximal inspiratory pressure (Pimax) and maximal expiratory pressure (Pemax) were measured with a differential pressure transducer (model MP-45, ± 350 cm H2O; Validyne Corp; Northridge, CA) while performing maximal inspiratory and
Respiratory Muscle Endurance Testing
Respiratory muscle endurance was tested using the same device that was used during hyperpnea training (see next section). Similar to the training sessions, the subjects were connected to a metabolic cart, and minute ventilation ( e), end-tidal CO2 (Petco2), and oxygen saturation were continuously monitored. The subjects were asked to maintain a target e of 70% of the 12-s maximum voluntary ventilation (MVV). The MVV was measured three times, and the best result was chosen. When
Exercise Testing and Quality of Life
An incremental symptom-limited exercise test was performed to determine the maximal work capacity of each subject. After a 3-min acclimatization period and 1 min of pedaling at 0 W, the workload was increased by 10 W every minute until the subject could no longer continue. The last workload for which a subject was able to complete 30 s of cycling was designated the maximal work capacity (Wmax).
Several days after the incremental exercise test, a constant workload exercise (endurance) test was
Quadriceps Fatigability
The purpose of obtaining measurements of quadriceps fatigability was to help determine the potential mechanisms for any improvement in exercise performance observed with hyperpneic training. Hyperpneic training has been thought by some to act as an ergonomic aid augmenting exercise performance at least in healthy subjects.15, 16 We hypothesized that hyperpneic training might reduce dyspnea during exercise and might allow subjects to advance more quickly during the endurance exercise sessions,
Endurance Training.
On the cycle ergometer, patients initially exercised at 50% of the Wmax achieved during the maximal incremental exercise test. When the patients could exercise for 20 min without intolerable dyspnea or leg fatigue (defined as a Borg rating of breathlessness and leg effort of ≤ 5 during exercise), the workload was increased by 10%. Treadmill exercise was started at a speed ranging from 1.1 to 2.0 miles per hour at 0% elevation based on the patient’s functional capacity (ie, on 6-min walk
Hyperpnea Training.
Subjects breathed from a rebreathing bag while obtaining fresh air through a side port. e and Petco2 were continuously recorded using a metabolic cart (Medgraphics; St. Paul, MN), and oxygen saturation was measured by pulse oximetry. Rebreathing bags of 1.5 to 2.0 L, depending on the patient’s vital capacity, were used, and the size of the bag was additionally adjusted with a clamp until stable normocapnia as estimated by the Petco2 was obtained during preliminary trials. If hypocapnia
Data Analysis
Data are expressed as the mean ± SE. Changes in variables over time and between groups were analyzed by repeated-measures analysis of variance. Baseline values for the two groups were compared by unpaired t test. A p value of < 0.05 was considered to be significant. A statistical software package was used for all calculations (StatView; SAS Institute; Cary, NC).
Results
The baseline characteristics of the 29 patients who completed the protocol are shown in Table 1. Patients had moderate-to-severe airflow obstruction with air trapping. The pulmonary function and demographics of the two groups were well-matched with no significant difference for any variable between groups. As expected, pulmonary function was unchanged after pulmonary rehabilitation (data not shown).
Training Sessions
Compliance during the rehabilitation program was excellent, as patients missed on average only 2 of 24 sessions (range, 0 to 6 sessions). Any sessions missed were made up at the end of the 8-week program to ensure that all of the subjects completed 24 sessions of training. The average duration of cycle and treadmill exercise during each session was similar in both groups. There was significant improvement in both cycle and treadmill performance in both groups (Table 2). The rate of progression
Effect of Training on Respiratory Muscle Strength and Endurance
At baseline, respiratory muscle strength and endurance were not significantly different between groups (Table 3). Pemax did not increase in either group after rehabilitation. Pimax significantly increased after training in the combined training group (p = 0.017) but not in the endurance training group. However, because Pimax did tend to increase in the endurance training group after training (p = 0.102), the difference in the extent of improvement between groups was not statistically
Effect of Training on Quality of Life
There were no differences at baseline in any of the quality-of-life domains between the two groups (Table 3). Both groups had statistically and clinically significant improvement in the dyspnea domain (endurance training group, p < 0.0001; combined training group, p = 0.0002) and fatigue domain (endurance training group, p = 0.0001; combined training group, p = 0.027) after rehabilitation, but there was no difference in the extent of improvement between groups. The minimal clinically
Effect of Training on Exercise Performance
At baseline, maximal exercise parameters were not significantly different between groups (Table 4). Maximal exercise capacity significantly improved in the endurance training group after rehabilitation (p = 0.0036), whereas the improvement in the combined training group after rehabilitation approached statistical significance (p = 0.07). There was no significant difference in the extent of improvement between the groups. At the same work rate, the heart rate decreased by 5% after rehabilitation
Effect of Training on Quadriceps Fatigability
TwQp values measured before and after exercise, prerehabilitation and postrehabilitation, are shown in Figure 1 for the endurance training group and the combined training group. In the endurance training group, the mean TwQp fell significantly after exercise prerehabilitation to a minimum of 78.0 ± 2.7% of the baseline value at 30 min after exercise. The mean TwQp fell less after exercise postrehabilitation, but this difference did not approach statistical significance. In the combined training
Discussion
The major findings of this study were as follows: (1) the addition of hyperpneic training to an endurance exercise program led to improvements in respiratory muscle endurance in patients with COPD beyond those achieved by endurance training alone; and (2) this improvement in respiratory muscle endurance did not translate into additional improvement in endurance exercise performance or quality of life compared with that achieved by an endurance exercise program alone.
Effects of Hyperpneic Training on Respiratory Muscle Endurance and Strength
Patients who underwent standard endurance exercise training demonstrated an improvement in respiratory muscle endurance. As expected, the hyperpneic training sessions led to a significantly greater improvement in respiratory muscle endurance than that achieved by endurance exercise alone. Thus, the hyperpneic training regimen was sufficient to train the respiratory muscles. Patients in the combined training group also demonstrated a significant increase in maximal inspiratory strength after
Effect of Hyperpneic Training on Exercise Performance and Quality of Life
Combined training did not result in any incremental improvement in exercise performance or quality of life compared with endurance training alone. Although the number of patients studied was relatively modest, there was no tendency for any measure of exercise performance to improve with combined therapy. Similar results have been obtained with inspiratory muscle-resistive or threshold-load training.4 Because normocapnic hyperpnea may more closely mimic the load faced by the respiratory muscles
Comparison to Healthy Subjects
Although such findings are still contentious, some studies15, 16 have shown that hyperpneic training can augment endurance exercise performance in healthy subjects. Improvements in endurance exercise performance were seen in both sedentary nonexercising subjects15 and competitive endurance athletes.16 Not surprisingly, no improvements were seen in maximum exercise capacity. Why then were benefits not seen in patients with COPD? Healthy subjects, if they exercise intensely enough, can develop
Effect of Hyperpneic Training on Limb Muscle Fatigability
In the combined training group, quadriceps fatigability was significantly reduced after training. In contrast, quadriceps fatigability was not significantly reduced after training in the endurance group alone. However, the extent of improvement with training was not significantly different between groups, because there was modest improvement with training in the endurance group as well. A reduction in quadriceps fatigability would be expected to improve endurance exercise performance, because
Acknowledgement
We thank Raymond Carter, LPN, for his help with the exercise training program, and Rosemary Cieslak for her secretarial support.
References (31)
- et al.
Measurement of health status: ascertaining the minimal clinically important difference
Control Clin Trials
(1989) - et al.
Exercise capacity and ventilatory, circulatory, and symptom limitation in patients with chronic airflow limitation
Am Rev Respir Dis
(1992) - et al.
Inspiratory muscle training in patients with chronic obstructive pulmonary disease: structural adaptation and physiologic outcomes
Am J Respir Crit Care Med
(2002) - et al.
Ventilatory muscle strength and endurance training
J Appl Physiol
(1976) - et al.
Effects of controlled inspiratory muscle training in patients with COPD: a meta-analysis
Eur Respir J
(2002) American College of Chest Physicians and American Association of Cardiovascular and Pulmonary Rehabilitation. Pulmonary rehabilitation: joint ACCP/AACVPR evidence-based guidelines: ACCP/AACVPR Pulmonary Rehabilitation Guidelines Panel
Chest
(1997)- et al.
Respiratory muscle endurance training in chronic obstructive pulmonary disease
Am J Respir Crit Care Med
(2000) - et al.
Ventilatory muscle training improves exercise capacity in chronic obstructive pulmonary disease patients
Am Rev Respir Dis
(1980) - et al.
Comparison of isocapnic hyperventilation and walking exercise training at home in pulmonary rehabilitation
Chest
(1986) - et al.
Evaluation of a ventilatory muscle endurance training program in the rehabilitation of patients with chronic obstructive pulmonary disease
Am Rev Respir Dis
(1986)
American Thoracic Society. Standardization of spirometry: 1994 update
Am J Respir Crit Care Med
Reference spirometric values using techniques and equipment that meet ATS recommendations
Am Rev Respir Dis
Standardized single breath normal values for carbon monoxide diffusing capacity
Am Rev Respir Dis
Lung volumes in healthy nonsmoking adults
Bull Eur Physiopathol Respir
A measure of quality of life for clinical trials in chronic lung disease
Thorax
Cited by (51)
Impact of high-intensity interval hyperpnea on aerobic energy release and inspiratory muscle fatigue
2024, Respiratory Physiology and NeurobiologyPulmonary rehabilitation outcomes in individuals with chronic obstructive pulmonary disease: A systematic review
2022, Annals of Physical and Rehabilitation MedicineCitation Excerpt :The agreement for 10% of the abstracts (187 records) reviewed by the 2 independent researchers was almost perfect, with Cohen's kappa 0.866 (95% confidence interval [CI] 0.76–0.97). Of the 267 included studies, 99 were observational studies [4,11–108], 87 were randomized controlled trials [109–195], 66 were quasi-experimental studies [105, 196–260], 9 had experimental designs [51, 261–268], 5 were pilot studies [269–273] and 1 was a mixed-methods study [274]. A total of 43,153 individuals with COPD were included in the studies.
Exercise Science and the Vocalist
2021, Journal of VoiceCitation Excerpt :More relevant for voice production is improved respiratory muscle endurance to reduce fatigue or improve vocal performance during extended periods of voicing, such as singing or sustained speaking (eg, teaching, lecturing). Respiratory muscle endurance can be trained in patients with conditions that restrict respiration, such as chronic pulmonary obstructive disease.23,24 In these cases, respiratory muscle endurance was measured by calculating maximum voluntary ventilation, a pulmonary function task.
The use of a modified, oscillating positive expiratory pressure device reduced fever and length of hospital stay in patients after thoracic and upper abdominal surgery: A randomised trial
2015, Journal of PhysiotherapyCitation Excerpt :This technique is a form of respiratory exercise that is typically used for individuals at high risk of PPCs. Oscillating positive expiratory pressure (PEP) devices have been shown to assist mucus clearance in a number of respiratory diseases, including: cystic fibrosis,6–9 chronic obstructive pulmonary disease,10,11 asthma,12 diffuse panbronchiolitis13 and bronchiectasis.14,15 In some of these studies, there is also some evidence that use of the oscillating PEP device may help to improve lung expansion, although the mechanism is unclear.
Inspiratory muscle training, with or without concomitant pulmonary rehabilitation, for chronic obstructive pulmonary disease (COPD)
2023, Cochrane Database of Systematic Reviews
Reproduction of this article is prohibited without written permission from the American College of Chest Physicians (www.chestjournal.org/misc/reprints.shtml).
Supported in part by Swiss National Science Foundation grant No. 31–61941.00.