Symptoms and quadriceps fatigability after walking and cycling in chronic obstructive pulmonary disease

The Influence of Lung Function and Respiratory Muscle Strength on Quadriceps Muscle Fatigability in COPD Patients Under Long-term Oxygen Therapy

BACKGROUND

This research investigates quadriceps muscle fatigability (MF) in chronic obstructive pulmonary disease (COPD) patients with chronic respiratory failure (CRF) at different levels of lung obstruction [severe obstruction (SO)=FEV1 <50% and >30% versus very severe obstruction (VSO)=FEV1 ≤30%]. It explores the relationships between quadriceps MF and lung function, respiratory muscles, and oxygenation status.

METHODS

A post hoc cross-over analysis in 45 COPD patients (20 SO and 25 VSO) undergoing long-term oxygen therapy was performed. Delta change in quadriceps maximum voluntary contraction (MVC) (absolute value and percentage) before and after a constant workload was calculated. Associations between quadriceps MF and lung function, respiratory muscles, and gas exchange were examined using Pearson's correlation and multivariate linear regression analysis.

RESULTS

SO patients experience a more substantial reduction in MVC compared to VSO (-15.15±9.13% vs -9.29±8.90%, p=0.0357), despite comparable resting MVC. Dyspnea is more pronounced in VSO at the beginning and end of the exercise. Correlations were found between MF and maximal inspiratory pressure (MIP) (r=-0.4412, p=0.0056), maximal expiratory pressure (MEP) (r=-0.3561, p=0.0282), and a tendency for FEV1% (r=-0.2931, p=0.0507). The regression model (R2=0.4719) indicates that lower MIP and FEV1 and high total lung capacity are significant factors in reducing quadriceps muscle fatigability after a fatiguing task.

CONCLUSION

COPD patients with more severe pulmonary obstruction and hyperinflation and lower respiratory muscle strength have lower quadriceps MF but higher dyspnea both at rest and during exercise.

Effects of Combined Endurance and Resistance Eccentric Training on Muscle Function and Functional Performance in Patients With Chronic Obstructive Pulmonary Disease: Randomized Controlled Trial

OBJECTIVE

To evaluate the adherence to treatment and efficacy of an eccentric-based training (ECC) program on peripheral muscle function and functional exercise capacity in patients with chronic obstructive pulmonary disease (COPD).

DESIGN

Prospective, assessor-blinded, randomized controlled trial.

SETTING

The cardiopulmonary rehabilitation unit of a tertiary subacute referral center.

PARTICIPANTS

Thirty (N=30) stable inpatients (mean age 68±8 years; FEV1 44±18% of predicted) with COPD were included in the study.

INTERVENTIONS

Inpatients were randomly assigned to 4 weeks of a combined endurance and resistance ECC (n=15) or conventional training (CON; n=15).

MAIN OUTCOME MEASURES

Quadriceps peak torque (PT) was the primary outcome measure for muscle function. Rate of force development (RFD), muscle activation and quality (quadriceps PT/leg lean mass), 6-min walk distance (6MWD), 4-meter gait speed (4mGS), 10-meter gait speed, 5-repetition sit-to-stand (5STS), dyspnea rate, and mortality risk were the secondary outcomes. Evaluations were performed at baseline and repeated after 4 weeks and 3 months of follow-up.

RESULTS

Quadriceps PT, RFD, and muscle quality improved by 17±23% (P<.001), 19±24%, and 16±20% (both P<.05) within the ECC group. Besides, a significant between-group difference for RFD (56±94 Nm/s, P=.038) was found after training. Both groups showed clinically relevant improvements in 6MWD, 4mGS, dyspnea rate, and mortality risk, with no significant differences between groups.

CONCLUSION

Combined endurance and resistance ECC improved lower limbs muscle function compared with CON in inpatients with COPD. In contrast, ECC did not further improve functional performance, dyspnea, and mortality risk. ECC may be of particular benefit to effect on skeletal muscle function in patients with COPD.

Fixed-intensity exercise tests to measure exertional dyspnoea in chronic heart and lung populations: a systematic review

INTRODUCTION

Exertional dyspnoea is the primary diagnostic symptom for chronic cardiopulmonary disease populations. Whilst a number of exercise tests are used, there remains no gold standard clinical measure of exertional dyspnoea. The aim of this review was to comprehensively describe and evaluate all types of fixed-intensity exercise tests used to assess exertional dyspnoea in chronic cardiopulmonary populations and, where possible, report the reliability and responsiveness of the tests.

METHODS

A systematic search of five electronic databases identified papers that examined 1) fixed-intensity exercise tests and measured exertional dyspnoea, 2) chronic cardiopulmonary populations, 3) exertional dyspnoea reported at isotime or upon completion of fixed-duration exercise tests, and 4) published in English.

RESULTS

Searches identified 8785 papers. 123 papers were included, covering exercise tests using a variety of fixed-intensity protocols. Three modes were identified, as follows: 1) cycling (n=87), 2) walking (n=31) and 3) other (step test (n=8) and arm exercise (n=2)). Most studies (98%) were performed on chronic respiratory disease patients. Nearly all studies (88%) used an incremental exercise test. 34% of studies used a fixed duration for the exercise test, with the remaining 66% using an exhaustion protocol recording exertional dyspnoea at isotime. Exertional dyspnoea was measured using the Borg scale (89%). 7% of studies reported reliability. Most studies (72%) examined the change in exertional dyspnoea in response to different interventions.

CONCLUSION

Considerable methodological variety of fixed-intensity exercise tests exists to assess exertional dyspnoea and most test protocols require incremental exercise tests. There does not appear to be a simple, universal test for measuring exertional dyspnoea in the clinical setting.

Effectiveness of Pulmonary Rehabilitation for Chronic Obstructive Pulmonary Disease Therapy: Focusing on Traditional Medical Practices

Chronic obstructive pulmonary disease (COPD) is a complex and serious disease that is characterized by dyspnea, fatigue, decreased exercise tolerance, peripheral muscle dysfunction, and mood disorders. These manifestations are successfully treated with pulmonary rehabilitation, a comprehensive intervention and holistic approach designed to improve the physical and psychological condition of people with COPD. Exercise is a big component of pulmonary rehabilitation programs, but the efficacy of non-traditional forms of exercise as used in alternative medicine is poorly understood. Here, we aim to address this gap in knowledge and summarize the clinical evidence for the use of traditional exercise regimens in the pulmonary rehabilitation of COPD patients.

Role of Nrf2 and exercise in alleviating COPD-induced skeletal muscle dysfunction

Chronic obstructive pulmonary disease (COPD) is a complex chronic respiratory disease with cumulative impacts on multiple systems, exhibiting significant extrapulmonary impacts, and posing a serious public health problem. Skeletal muscle dysfunction is one of the most pronounced extrapulmonary effects in patients with COPD, which severely affects patient prognosis and mortality primarily through reduced productivity resulting from muscle structural and functional alterations. Although the detailed pathogenesis of COPD has not been fully determined, some researchers agree that oxidative stress plays a significant role. Oxidative stress not only catalyzes the progression of pulmonary symptoms but also drives the development of skeletal muscle dysfunction. Nuclear factor erythroid 2-related factor 2 (Nrf2), is a key transcription factor that regulates the antioxidant response and plays an enormous role in combating oxidative stress. In this review, we have summarized current research on oxidative stress damage to COPD skeletal muscle and analyzed the role of Nrf2 in improving skeletal muscle dysfunction in COPD through exercise. The results suggest that oxidative stress drives the occurrence and development of skeletal muscle dysfunction in COPD. Exercise may improve skeletal muscle dysfunction in patients with COPD by promoting the dissociation of Kelch-like ECH-associated protein 1 (Keap1) and Nrf2, inducing sequestosome1(p62) phosphorylation to bind with Keap1 competitively leading to Nrf2 stabilization and improving dynamin-related protein 1-dependent mitochondrial fission. Nrf2 may be a key target for exercise anti-oxidative stress to alleviate skeletal muscle dysfunction in COPD.

Examining the repeatability of a novel test to measure exertional dyspnoea in chronic obstructive pulmonary disease

BACKGROUND

Exertional dyspnoea(ED) is a hallmark of chronic obstructive pulmonary disease(COPD). We examined the repeatability and face validity of the end-exercise ED(ED_end) response during the Dyspnoea Challenge and compared those to the six-minute walk test (6MWT) in COPD.

METHODS

Twenty-six individuals with COPD(13 Females, age:69 ± 5.5yrs, FEV₁:63.4 ± 11.9 %) completed 2 × 6MWTs and 4 x Dyspnoea Challenges on three occasions. The challenge consisted of a two-minute treadmill walk at 80 % of 6MWT speed(3.9 ± 0.5 km·hr^-1) at either a low(LI_DC:5.3 ± 2%) or high angle of incline(HI_DC:9.5 ± 3%). Dyspnoea(0-10 scale), heart rate(HR) and oxygen saturation(S_pO₂) were monitored continuously.

RESULTS

Mean 6MWT distance was 488 ± 58 m. End-exercise ED and HR were higher in the HI_DC(ED_end 6.2 ± 2.0; HR: 123 ± 17beats·min^-1) compared to the LI_DC(ED_end 4.2 ± 2.0; HR: 119 ± 15beats·min^-1) and the 6MWT(ED_end 4.3 ± 2.0; HR: 115 ± 16beats·min^-1)(P < 0.01). SpO₂ was not different between 6MWT, LI_DC or HI_DC(P = 0.34). The intraclass correlation coefficient(ICC) for each intensity was excellent (HI_DC, ICC = 0.88, LI_DC, ICC = 0.93, P < 0.001) with neither reporting bias(HI_DC, P = 0.63; LI_DC, P = 0.94).

CONCLUSIONS

The Dyspnoea Challenge is a simple measure of ED that appears to have both repeatability and face validity. With further optimisation, this test may enhance the field-based clinical assessment of ED.

Impact of fan therapy during exercise on breathlessness and recovery time in patients with COPD: a pilot randomised controlled crossover trial

Background

Patients with COPD reduce physical activity to avoid the onset of breathlessness. Fan therapy can reduce breathlessness at rest, but the efficacy of fan therapy during exercise remains unknown in this population. The aim of the present study was to investigate 1) the effect of fan therapy on exercise-induced breathlessness and post-exercise recovery time in patients with COPD and 2) the acceptability of fan therapy during exercise; and 3) to assess the reproducibility of any observed improvements in outcome measures.

Methods

A pilot single-centre, randomised, controlled, crossover open (nonmasked) trial (clinicaltrials.gov NCT03137524) of fan therapy versus no fan therapy during 6-min walk test (6MWT) in patients with COPD and a modified Medical Research Council (mMRC) dyspnoea score ≥2. Breathlessness intensity was quantified before and on termination of the 6MWT, using the numerical rating scale (NRS) (0–10). Post-exertional recovery time was measured, defined as the time taken to return to baseline NRS breathlessness score. Oxygen saturation and heart rate were measure pre- and post-6MWT.

Results

14 patients with COPD completed the trial per protocol (four male, 10 female; median (interquartile range (IQR)) age 66.50 (60.75 to 73.50) years); mMRC dyspnoea 3 (2 to 3)). Fan therapy resulted in lower exercise-induced breathlessness (ΔNRS; Δ modified Borg scale) (within-individual differences in medians (WIDiM) −1.00, IQR −2.00 to −0.50; p<0.01; WIDiM −0.25, IQR −2.00 to 0.00; p=0.02), greater distance walked (metres) during the 6MWT (WIDiM 21.25, IQR 12.75 to 31.88; p<0.01), and improved post-exertional breathlessness (NRS) recovery time (WIDiM −10.00, IQR −78.75 to 50.00; p<0.01). Fan therapy was deemed to be acceptable by 92% of participants.

Conclusion

Fan therapy was acceptable and provided symptomatic relief to patients with COPD during exercise. These data will inform larger pilot studies and efficacy studies of fan therapy during exercise.

Fan therapy was acceptable and provided symptomatic relief to patients with COPD during exercise; these positive preliminary findings suggest that fan therapy merits further investigation in larger and more methodologically rigorous studieshttps://bit.ly/3xR2GDW

Psychometric properties of the Korean version of the Pittsburgh Fatigability Scale in breast cancer survivors

BACKGROUND

Fatigability has recently emerged in oncology as a concept that anchors patients' perceptions of fatigue to defined activities of specified duration and intensity. This study aimed to examine the psychometric properties of the Korean version of the Pittsburgh Fatigability Scale (K-PFS) for women with breast cancer.

METHODS

This cross-sectional study involved 196 women with breast cancer recruited from a tertiary hospital in Seoul, Korea. Reliability was evaluated using Cronbach's alpha, and confirmatory factor analysis was conducted to examine the factor structure of the K-PFS. Four goodness-of-fit values were evaluated: (1) the comparative fit index (CFI), (2) the Tucker-Lewis index (TLI), (3) the root mean square error of approximation (RMSEA), and (4) the standardized root mean square residual (SRMR).

RESULTS

Of the 196 survivors, 71.1% had greater physical fatigability (K-PFS Physical score ≥ 15) and 52.6% had greater mental fatigability (K-PFS Mental score ≥ 13). The Cronbach's alpha coefficient for the total K-PFS scale was 0.926, and the coefficients for the physical and mental fatigability domains were 0.870 and 0.864, respectively. In the confirmatory factor analysis for physical fatigability, the SRMR value (0.076) supported goodness of fit, but other model fit statistics did not (CFI = 0.888, TLI = 0.826, and RMSEA = 0.224). For mental fatigability, although three goodness-of-fit values were acceptable (CFI = 0.948, TLI = 0.919, and SRMR = 0.057), the RMSEA value (0.149) did not indicate good model fit. However, each item coefficient was statistically significant (> 0.5), and the K-PFS was therefore found to be valid from a theoretical perspective.

CONCLUSION

This study provides meaningful information on the reliability and validity of the K-PFS instrument, which was developed to meet an important need in the context of breast cancer survivors. Additional research should examine its test-retest reliability and construct validity with performance measures.

The correlation between quadriceps muscle strength and endurance and exercise performance in patients with COPD

To determine the association between quadriceps muscle strength (QMS) and endurance (QME) and exercise capacity in patients with COPD after stratification for sex and resting lung function (LF). Data were collected from 3,246 patients with COPD (60% men, 64 ± 9 yr), including measures of exercise capacity [peak aerobic capacity (peakV̇o₂), 6-min walk distance (6MWD)] and isokinetic QMS and QME. Patients were stratified for sex, forced expiratory volume in 1 s (>50/≤50% predicted), single breath carbon monoxide diffusing capacity (>50/≤50% predicted), and residual volume (>140/≤140% predicted). After stratification for resting LF, QMS and QME were significantly associated with peakV̇o₂ (r range: 0.47-0.61 and 0.49-0.65 for men and 0.53-0.66 and 0.48-0.67 for women, respectively) and 6MWD (r range: 0.29-0.42 and 0.44-0.55 for men and 0.25-0.54 and 0.34-0.55 for women, respectively) (P < 0.001). Regression models demonstrated that QMS and QME were significant determinants of peakV̇o₂ (explained variance R² range: 35.6%-48.8% for men and 36.8%-49.0% for women) and 6MWD (R² range: 24.3%-43.3% for men and 28.4%-40.3% for women), independent of age and fat-free mass. Quadriceps muscle function was significantly associated with peakV̇o₂ and 6MWD in male and female patients with COPD after stratification for resting LF, in which QME appear to be a more important determinant than QMS. This underlines the importance of systematically evaluating both quadriceps muscle strength and endurance in in all patients with COPD.NEW & NOTEWORTHY Our findings identified quadriceps muscle function as an important determinant of exercise capacity across a wide spectrum of lung function. Quadriceps muscle endurance appears to be a more important determinant than quadriceps muscle strength, underlining the importance of including both the measurement of quadriceps muscle strength and endurance in routine assessment for all patient with COPD.

The role of peripheral muscle fatigability on exercise intolerance in COPD

INTRODUCTION

Exercise limitation in chronic obstructive pulmonary disease (COPD) is multi-factorial; however, growing evidence indicates that muscle dysfunction may contribute in some patients.

AREAS COVERED

This work outlines current evidence for and against increased peripheral muscle fatigability in COPD through a comprehensive review of relevant literature available on PubMed/MEDLINE until May 2020. The authors first discuss key methodological issues relative to muscle fatigue assessment by non-volitional techniques, particularly magnetic stimulation. The authors then provide a detailed discussion of critical studies to have objectively measured skeletal muscle fatigue in individuals with COPD.

EXPERT OPINION

Current evidence indicates that localized (knee extension) and cycling exercise are associated with increased quadriceps fatigability in most COPD patients. Increased fatigability, however, has not been consistently found in response to walking, likely reflecting the tendency of 'central' respiratory constraints to overshadow potential functional impairments in the appendicular muscles in this form of exercise. Thus, addressing skeletal muscle abnormalities may be critical to translate improvements in lung mechanics (e.g., due to bronchodilator therapy) into better exercise tolerance. The positive effects of pulmonary rehabilitation on muscle fatigability are particularly encouraging and suggest a role for these measurements to test the efficacy of emerging adjunct training strategies focused on the peripheral muscles.

High-Flow Oxygen Therapy During Exercise Training in Patients With Chronic Obstructive Pulmonary Disease and Chronic Hypoxemia: A Multicenter Randomized Controlled Trial

OBJECTIVE

The study aimed to evaluate whether high-flow oxygen therapy (HFOT) during training was more effective than oxygen in improving exercise capacity in hypoxemic chronic obstructive pulmonary disease (COPD).

METHODS

A total of 171 patients with COPD and chronic hypoxemia were consecutively recruited in 8 rehabilitation hospitals in a randomized controlled trial. Cycle-ergometer exercise training was used in 20 supervised sessions at iso inspiratory oxygen fraction in both groups. Pre- and post-training endurance time (Tlim), 6-minute walking distance (6MWD), respiratory and limb muscle strength, arterial blood gases, Barthel Index, Barthel Dyspnea Index, COPD Assessment Test, Maugeri Respiratory Failure questionnaire, and patient satisfaction were evaluated.

RESULTS

Due to 15.4% and 24.1% dropout rates, 71 and 66 patients were analyzed in HFOT and Venturi mask (V-mask) groups, respectively. Exercise capacity significantly improved after training in both groups with similar patient satisfaction. Between-group difference in post-training improvement in 6MWD (mean: 17.14 m; 95% CI = 0.87 to 33.43 m) but not in Tlim (mean: 141.85 seconds; 95% CI = -18.72 to 302.42 seconds) was significantly higher in HFOT. The minimal clinically important difference of Tlim was reached by 47% of patients in the V-mask group and 56% of patients in the HFOT group, whereas the minimal clinically important difference of 6MWD was reached by 51% of patients in the V-mask group and 69% of patients in the HFOT group, respectively.

CONCLUSION

In patients with hypoxemic COPD, exercise training is effective in improving exercise capacity.

IMPACT STATEMENT

The addition of HFOT during exercise training is not more effective than oxygen through V-mask in improving endurance time, the primary outcome, whereas it is more effective in improving walking distance.

Pulmonary Rehabilitation for Chronic Obstructive Pulmonary Disease: Highly Effective but Often Overlooked

Patients with chronic obstructive pulmonary disease receive a range of treatments including but not limited to inhaled bronchodilators, inhaled and systemic corticosteroids, supplemental oxygen, and pulmonary rehabilitation. Pulmonary rehabilitation is a multidisciplinary intervention that seeks to combine patient education, exercise, and lifestyle changes into a comprehensive program. Programs 6 to 8 weeks in length have been shown to improve health, reduce dyspnea, increase exercise capacity, improve psychological well-being, and reduce healthcare utilization and hospitalization. Although the use of pulmonary rehabilitation is widely supported by the literature, controversy still exists regarding what should be included in the programs. The goal of this review was to summarize the evidence for pulmonary rehabilitation and identify the areas that hold promise in improving its utilization and effectiveness.

Effects of downhill walking in pulmonary rehabilitation for patients with COPD: a randomised controlled trial

The development of contractile muscle fatigue (CMF) affects training responses in patients with chronic obstructive pulmonary disease (COPD). Downhill walking induces CMF with lower dyspnoea and fatigue than level walking. This study compared the effect of pulmonary rehabilitation (PR) comprising downhill walking training (DT) to PR comprising level walking (conventional training (CT)) in patients with COPD.

In this randomised controlled trial, 35 patients (62±8 years; forced expiratory volume in 1 s (FEV1) 50±17% predicted) were randomised to DT or CT. Exercise tolerance (6-minute walk test distance (6MWD); primary outcome), muscle function, symptoms, quality-of-life and physical activity levels were assessed before and after PR. Absolute training changes and the proportion of patients exceeding the 30 m 6MWD minimally important difference (MID) were compared between groups. Quadriceps muscle biopsies were collected after PR in a subset of patients to examine physiological responses to long-term eccentric training.

No between-group differences were observed in absolute 6MWD improvement (mean 6MWD change 77±46 m DT versus 56±47 m CT; p=0.45), however 94% of patients in DT exceeded the 6MWD MID compared to 65% in CT (p=0.03). Patients in DT tended to have larger improvements than CT in other outcomes. Muscle biopsy analyses did not differ between groups.

PR incorporating downhill walking confers similar magnitudes of effects to PR with conventional walking across clinical outcomes in patients with COPD, however, offers a more reliable stimulus to maximise the achievement of clinically relevant gains in functional exercise tolerance in people with COPD.

Locomotor Muscles in COPD: The Rationale for Rehabilitative Exercise Training

Exercise training as part of pulmonary rehabilitation is arguably the most effective intervention to improve tolerance to physical exertion in patients with chronic obstructive pulmonary disease (COPD). Owing to the fact that exercise training has modest effects on exertional ventilation, operating lung volumes and respiratory muscle performance, improving locomotor muscle structure and function are key targets for pulmonary rehabilitation in COPD. In the current concise review, we initially discuss whether patients’ muscles are exposed to deleterious factors. After presenting corroboratory evidence on this regard (e.g., oxidative stress, inflammation, hypoxemia, inactivity, and medications), we outline their effects on muscle macro- and micro-structure and related functional properties. We then finalize by addressing the potential beneficial consequences of different training strategies on these muscle-centered outcomes. This review provides, therefore, an up-to-date outline of the rationale for rehabilitative exercise training approaches focusing on the locomotor muscles in this patient population.

Comparative measurement properties of constant work rate cycling and the endurance shuttle walking test in COPD: the TORRACTO® clinical trial

BACKGROUND

Exercise tolerance is an important endpoint in chronic obstructive pulmonary disease (COPD) clinical trials. Little is known about the comparative measurement properties of constant work rate cycle ergometry (CWRCE) and the endurance shuttle walking test (ESWT). The objective of this sub-analysis of the TORRACTO® study was to directly compare the endurance measurement properties of CWRCE and ESWT in patients with COPD in a multicentre, multinational setting. We predicted that both tests would be similarly reliable, but that the ESWT would be more responsive to bronchodilation than CWRCE.

METHODS

This analysis included 151 patients who performed CWRCE and ESWT at baseline and week 6 after receiving once-daily placebo, tiotropium/olodaterol (T/O) 2.5/5 μg or T/O 5/5 μg. Reproducibility was assessed by comparing their respective performance at baseline and week 6 in the placebo group. Responsiveness to bronchodilation was assessed by comparing endurance time at week 6 with T/O with baseline values and placebo. The locus of symptom limitation and end-exercise Borg scales for breathing and leg discomfort for both tests were also analysed.

RESULTS

The intraclass correlation coefficients for CWRCE and ESWT were 0.56 [95% confidence interval (CI) 0.37-0.71] and 0.75 (95% CI 0.63-0.84). More patients were limited by breathing discomfort during the ESWT than during CWRCE, whereas more patients were limited by leg discomfort or breathing/leg discomfort during CWRCE than the ESWT (p <0.0001). Both tests were responsive to bronchodilator treatment: there was a 19% increase in endurance time from baseline at week 6 (p = 0.0006) assessed with CWRCE, and a 20% increase in endurance time assessed with ESWT (p = 0.0013).

CONCLUSIONS

Both exercise tests performed well in a multicentre clinical trial. Although the locus of symptom limitation differed between the two tests, both were reliable and responsive to bronchodilation. For future clinical trials, the choice of test should depend on the study requirements.

CLINICALTRIALS.GOV IDENTIFIER

NCT01525615. The reviews of this paper are available via the supplemental material section.

ERS statement on standardisation of cardiopulmonary exercise testing in chronic lung diseases

The objective of this document was to standardise published cardiopulmonary exercise testing (CPET) protocols for improved interpretation in clinical settings and multicentre research projects. This document: 1) summarises the protocols and procedures used in published studies focusing on incremental CPET in chronic lung conditions; 2) presents standard incremental protocols for CPET on a stationary cycle ergometer and a treadmill; and 3) provides patients' perspectives on CPET obtained through an online survey supported by the European Lung Foundation. We systematically reviewed published studies obtained from EMBASE, Medline, Scopus, Web of Science and the Cochrane Library from inception to January 2017. Of 7914 identified studies, 595 studies with 26 523 subjects were included. The literature supports a test protocol with a resting phase lasting at least 3 min, a 3-min unloaded phase, and an 8- to 12-min incremental phase with work rate increased linearly at least every minute, followed by a recovery phase of at least 2–3 min. Patients responding to the survey (n=295) perceived CPET as highly beneficial for their diagnostic assessment and informed the Task Force consensus. Future research should focus on the individualised estimation of optimal work rate increments across different lung diseases, and the collection of robust normative data.

The document facilitates standardisation of conducting, reporting and interpreting cardiopulmonary exercise tests in chronic lung diseases for comparison of reference data, multi-centre studies and assessment of interventional efficacy.http://bit.ly/31SXeB5

Activin Type II Receptor Blockade for Treatment of Muscle Depletion in Chronic Obstructive Pulmonary Disease. A Randomized Trial

RATIONALE

Bimagrumab is a fully human monoclonal antibody that blocks the activin type II receptors, preventing the activity of myostatin and other negative skeletal muscle regulators.

OBJECTIVES

To assess the effects of bimagrumab on skeletal muscle mass and function in patients with chronic obstructive pulmonary disease (COPD) and reduced skeletal muscle mass.

METHODS

Sixty-seven patients with COPD (mean FEV₁, 1.05 L [41.6% predicted]; aged 40-80 yr; body mass index < 20 kg/m² or appendicular skeletal muscle mass index ≤ 7.25 [men] and ≤ 5.67 [women] kg/m²), received two doses of either bimagrumab 30 mg/kg intravenously (n = 33) or placebo (n = 34) (Weeks 0 and 8) over 24 weeks.

MEASUREMENTS AND MAIN RESULTS

We assessed changes in thigh muscle volume (cubic centimeters) as the primary endpoint along with 6-minute-walk distance (meters), safety, and tolerability. Fifty-five (82.1%) patients completed the study. Thigh muscle volume increased by Week 4 and remained increased at Week 24 in bimagrumab-treated patients, whereas no changes were observed with placebo (Week 4: +5.9% [SD, 3.4%] vs. 0.0% [3.3%], P < 0.001; Week 8: +7.0% [3.7%] vs. -0.7% [2.8%], P < 0.001; Week 16: +7.8% [5.1%] vs. -0.9% [4.5%], P < 0.001; Week 24: +5.0% [4.9%] vs. -1.3% [4.3%], P < 0.001). Over 24 weeks, 6-minute-walk distance did not increase significantly in either group. Adverse events in the bimagrumab group included muscle-related symptoms, diarrhea, and acne, most of which were mild in severity.

CONCLUSIONS

Blocking the action of negative muscle regulators through the activin type II receptors with bimagrumab treatment safely increased skeletal muscle mass but did not improve functional capacity in patients with COPD and low muscle mass. Clinical trial registered with www.clinicaltrials.gov (NCT01669174).

Exercise Training Modalities for People with Chronic Obstructive Pulmonary Disease

Exercise training confers health benefits for people with chronic obstructive pulmonary disease (COPD). This article reviews the evidence for several exercise training modalities shown to be beneficial among individuals with COPD. These modalities include aerobic, resistance, nonlinear periodized, upper limb and balance training, as well as yoga, Tai Chi, inspiratory muscle training, whole body vibration training and neuromuscular electrical stimulation. The literature pertaining to each modality was critically reviewed, and information on the rationale, mechanism(s) of action (where known), benefits, and exercise prescription is described to facilitate easy implementation into clinical practice.

Physiological and Symptomatic Responses to Arm versus Leg Activities in People with Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

While the mechanisms underlying exercise limitations and symptoms during leg activities have been investigated in detail, knowledge of potential differences between leg and arm activities are not well understood and results from individual studies are contradictory. Thus, the aim of the present study was to synthesize physiological and symptomatic responses during activities involving the arms relative to activities involving the legs in people with Chronic Obstructive Pulmonary Disease (COPD). Any study with a cross-sectional comparison of acute physiological (cardiorespiratory, metabolic) and symptomatic responses to activities performed with the arms versus the legs were included. Studies were sub-grouped based on the type of activity performed (cycle ergometer, resistance exercises, or functional test/activities). Eighteen studies with 423 individuals with COPD were included. Leg cycle ergometer resulted in greater tidal volume (137 mL), minute ventilation (4.8 L/min), and oxygen consumption (164 mL/min) than arm cycle ergometer, while symptomatic responses were similar. Resistance exercises resulted in similar physiological and symptomatic responses irrespective of whether the legs or the arms were involved while studies on functional activities report different results depending on the type and intensity of the activity performed. With the exception of cycle ergometer activities, physiological and symptomatic responses do not seem to depend on whether the arms or the legs are used, but rather seem to be task and intensity dependent. These novel findings suggest, for example, that strategies used to increase exercise tolerance should not be dependent on whether the arms or the legs are used, but rather the intensity of specific activity performed.

Physiological and perceptual responses to exercise according to locus of symptom limitation in COPD

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease, with pulmonary and extra-pulmonary factors contributing to exercise intolerance. The primary self-reported exercise-limiting symptom may reflect the primary pathophysiological factor contributing to exercise intolerance. We compared physiological and perceptual responses at the symptom-limited peak of incremental cardiopulmonary cycle exercise testing between people with COPD reporting breathlessness (B, n = 34), leg discomfort (LD, n = 16), or a combination of B and LD (BOTH, n = 42) as their main exercise-limiting symptom(s). Despite similarly impaired health status, symptomology and peak exercise capacity, the B group had greater restrictive constraints on tidal volume expansion at end-exercise and was more likely to report unpleasant qualities of exertional breathlessness than LD and BOTH groups. In conclusion, reporting breathlessness as the primary exercise-limiting symptom indicated the presence of distinct lung pathophysiology and symptom perception during exercise in people with COPD.

Personalized exercise training in chronic lung diseases

Chronic respiratory diseases (CRD) are characterized by exertional dyspnoea, exercise limitation and reduced health-related quality of life (QoL). Exercise training is essential for improving symptoms, physical function and QoL. Current research available supports the effectiveness of exercise training in patients with chronic obstructive pulmonary disease (COPD), cystic fibrosis and interstitial lung disease (ILD). However, recent studies have also shown safety and effectiveness of exercise training in patients with pulmonary arterial hypertension (PAH) and asthma. Despite the lack of clinical guidelines for exercise training in PAH, a recent Cochrane review has reported improvements in functional capacity and effective reductions in mean pulmonary arterial pressure. In the other CRD, a number of Cochrane reviews, supported by numerous randomized controlled trials, have been published outlining the benefits of different types of exercise training. The aim of this review is to establish the principles and modalities of personalized exercise training and the effects of exercise training across a number of CRD. In addition, this review provides information on personalized exercise prescription for CRD patients with co-morbidities.

Exercise assessments and trainings of pulmonary rehabilitation in COPD: a literature review

Skeletal muscle dysfunction leads to reduction in activity in patients with COPD. As an essential part of the management of COPD, pulmonary rehabilitation (PR) alleviates dyspnea and fatigue, improves exercise tolerance and health-related quality of life, and reduces hospital admissions and mortality for COPD patients. Exercise is the key component of PR, which is composed of exercise assessment and training therapy. To evaluate PR’s application in clinical practice, this article summarizes the common methods of exercise measurement and exercise training for patients with COPD. Exercise assessments should calculate patients’ symptoms, endurance, strength, and health-related quality of life. After calculation, detailed exercise therapies should be developed, which may involve endurance, strength, and respiratory training. The detailed exercise training of each modality is mentioned in this review. Although various methods and therapies of PR have been used in COPD patients, developing an individualized exercise training prescription is the target. More studies are warranted to support the evidence and examine the effects of long-term benefits of exercise training for patients with COPD in each stage.

Effectiveness of Pulmonary Rehabilitation in Patients With Chronic Obstructive Pulmonary Disease With Different Degrees of Static Lung Hyperinflation

OBJECTIVE

To evaluate the effect of pulmonary rehabilitation (PR) on exercise performance and quality of life in patients with chronic obstructive pulmonary disease (COPD) with different degrees of static lung hyperinflation (LH).

DESIGN

Retrospective cohort study.

SETTING

PR network.

PARTICIPANTS

A cohort of 1981 patients with COPD (55% men; age: 66.8±9.3y; forced expiratory volume in the first second%: 50.7±19.5; residual volume [RV]%: 163.0±49.7).

INTERVENTION

An interdisciplinary PR program for patients with COPD consisting of 40 sessions.

MAIN OUTCOME MEASURES

Participants were stratified into 5 quintiles according to baseline RV and were evaluated on the basis of pre- and post-PR 6-minute walk distance (6MWD), constant work rate test (CWRT), and Saint George's Respiratory Questionnaire (SGRQ), among other clinical parameters.

RESULTS

With increasing RV quintile, patients were younger, more frequently women, had lower forced expiratory volume in the first second%, lower body mass index and fat-free mass index, shorter 6MWD, shorter CWRT, and worse SGRQ scores (P<.01). All RV strata improved after PR in all 3 outcomes (P<.001). Nevertheless, higher, compared to lower RV categories, had lower ΔCWRT (P<.01) but similar Δ6MWD (P=.948) and ΔSGRQ (P=.086) after PR.

CONCLUSIONS

LH in COPD is related to younger age, female sex, lower body weight, worse exercise capacity and health status, but did not prevent patients from benefitting from PR. LH, however, influences walking and cycling response after PR differently.

Prescribing Cycle Exercise Intensity Using Moderate Symptom Levels in Chronic Obstructive Pulmonary Disease

PURPOSE

Laboratory-based cardiopulmonary exercise testing from which to prescribe cycle training intensity in pulmonary rehabilitation for people with chronic obstructive pulmonary disease (COPD) is not readily available in clinical practice. Alternative methods of prescribing cycle exercise intensity, such as patient symptoms of dyspnea or rating of perceived exertion (RPE), have been used, but it is unknown whether cycle intensity based on such symptoms elicits an exercise intensity appropriate for achieving physiological training responses. The aim of the study was to determine the exercise intensity elicited when continuous cycle exercise was prescribed at symptoms of moderate dyspnea or RPE in people with COPD.

METHODS

Participants with diagnosed COPD performed lung function tests and an incremental cycle test to peak work capacity. On a subsequent day, participants performed 10 minutes of cycle exercise based on moderate symptoms (CycleSYMP) of either dyspnea or RPE, depending on which symptom limited the incremental cycle test. Oxygen uptake ((Equation is included in full-text article.)O2) was measured during all exercise using a portable metabolic system (Cosmed K4b).

RESULTS

Thirty participants, mean age of 70 ± 9 years and FEV1 60 ± 12% predicted, completed the study. The mean intensity achieved during CycleSYMP was 78 ± 12%(Equation is included in full-text article.)O2peak and 71 ± 18 % (Equation is included in full-text article.)O2Reserve. Steady-state (Equation is included in full-text article.)O2 was achieved by the sixth minute of CycleSYMP.

CONCLUSIONS

Using symptoms of moderate dyspnea or RPE as a method of prescribing cycle exercise elicited a high training intensity at which steady-state was achieved in people with mild to moderate COPD.

COPD online-rehabilitation versus conventional COPD rehabilitation - rationale and design for a multicenter randomized controlled trial study protocol (CORe trial)

BACKGROUND

Rehabilitation of patients with chronic obstructive pulmonary disease (COPD) is a key treatment in COPD. However, despite the existing evidence and a strong recommendation from lung associations worldwide, 50% of patients with COPD decline to participate in COPD rehabilitation program and 30-50% drop-out before completion. The main reasons are severe symptoms, inflexible accessibility and necessity for transportation. Currently there are no well-established and evident rehabilitation alternatives. Supervised online screen rehabilitation could be a useful approach to increase accessibility and compliance. The aim of this multicenter RCT study is to compare the potential benefits of a 10-week online COPD rehabilitation program (CORe) with conventional outpatient COPD rehabilitation (CCRe).

METHODS

This study is a randomized assessor- and statistician blinded superiority multicenter trial with two parallel groups, employing 1:1 allocation to the intervention and the comparison group.On the basis of a sample size calculation, 134 patients with severe or very severe COPD and eligible to conventional hospital based outpatient COPD rehabilitation will be included and randomized from eight different hospitals. The CORe intervention group receives group supervised resistance- and endurance training and patient education, 60 min, three times/week for 10 weeks at home via online-screen. The CCRe comparison group receives group based supervised resistance- and endurance training and patient education, 90 min, two times/week for 10 weeks (two hospitals) or 12 weeks (six hospitals) in groups at the local hospital. The primary outcome is change in the 6-min walking distance after 10/12 weeks; the secondary outcomes are changes in 30 s sit-to-stand chair test, physical activity level, symptoms, anxiety and depression symptoms, disease specific and generic quality of life. Primary endpoint is 10/12 weeks from baseline, while secondary endpoints are 22, 36, 62 weeks from baseline assessments.

DISCUSSION

The study will likely contribute to knowledge regarding COPD tele-rehabilitation and to which extent it is more feasible and thereby more efficient than conventional COPD rehabilitation in patients with severe and very severe COPD.

TRIAL REGISTRATION

Clinicaltrials.gov Identifier: NCT02667171 . Registration data: January 28th 2016.

Angiotensin-Converting Enzyme Inhibition as an Adjunct to Pulmonary Rehabilitation in Chronic Obstructive Pulmonary Disease

RATIONALE

Epidemiological studies in older individuals have found an association between the use of angiotensin-converting enzyme (ACE) inhibition (ACE-I) therapy and preserved locomotor muscle mass, strength, and walking speed. ACE-I therapy might therefore have a role in the context of pulmonary rehabilitation (PR).

OBJECTIVES

To investigate the hypothesis that enalapril, an ACE inhibitor, would augment the improvement in exercise capacity seen during PR.

METHODS

We performed a double-blind, placebo-controlled, parallel-group randomized controlled trial. Patients with chronic obstructive pulmonary disease, who had at least moderate airflow obstruction and were taking part in PR, were randomized to either 10 weeks of therapy with an ACE inhibitor (10 mg enalapril) or placebo.

MEASUREMENTS AND MAIN RESULTS

The primary outcome measurement was the change in peak power (assessed using cycle ergometry) from baseline. Eighty patients were enrolled, 78 were randomized (age 67 ± 8 years; FEV₁ 48 ± 21% predicted), and 65 completed the trial (34 on placebo, 31 on the ACE inhibitor). The ACE inhibitor-treated group demonstrated a significant reduction in systolic blood pressure (Δ, -16 mm Hg; 95% confidence interval [CI], -22 to -11) and serum ACE activity (Δ, -18 IU/L; 95% CI, -23 to -12) versus placebo (between-group differences, P < 0.0001). Peak power increased significantly more in the placebo group (placebo Δ, +9 W; 95% CI, 5 to 13 vs. ACE-I Δ, +1 W; 95% CI, -2 to 4; between-group difference, 8 W; 95% CI, 3 to 13; P = 0.001). There was no significant between-group difference in quadriceps strength or health-related quality of life.

CONCLUSIONS

Use of the ACE inhibitor enalapril, together with a program of PR, in patients without an established indication for ACE-I, reduced the peak work rate response to exercise training in patients with chronic obstructive pulmonary disease.

Assessment of dyspnea and dynamic hyperinflation in male patients with chronic obstructive pulmonary disease during a six minute walk test and an incremental treadmill cardiorespiratory exercise test

The six minute walk test (6MWT) is a standardized test that provides information on exercise capacity in patients with COPD. It is considered a submaximal test in opposition to incremental cardiopulmonary exercise tests (CPET) that provide valuable information on all the systems involved in exercise.

OBJECTIVES

1. To compare the perceptive, physiological responses and degree of dynamic hyperinflation during two exercise tests: the 6MWT and the incremental CPET on a treadmill. 2. To evaluate how dyspnea is related to dynamic hyperinflation (DH) and other functional parameters in both tests.

METHODS

29 stable COPD male patients, age 68±5.8 years, mean post-bronchodilator FEV1 57±11%, were recruited. To evaluate dynamic hyperinflation, inspiratory capacity (IC) was measured at rest and upon completing each one of the tests. At the same time, perceived dyspnea and leg discomfort were rated on specific modified Borg scales.

RESULTS

The mean walk distance in 6MWT was 494±88m. The Borg scale rating for shortness of breath upon completing the test was 4.7±2, whilst 2.9±2 for leg discomfort. IC changed from 2.53±0.63l before to 2.34±0.60l after completion of the test. In the treadmill CPET, maximal oxygen consumption (V˙O₂max) was 21.8±5mL/kg/min with 6.6±2 dyspnea and 4.3±2 leg discomfort on Borg scales. IC changed from 2.17±0.53l to 1.20±0.43l.

CONCLUSIONS

Dynamic hyperinflation occurs in male COPD patients during submaximal exercise such as the 6MWT. This phenomenon is more pronounced after incremental CPET on a treadmill. Despite being dyspnea the dominant limiting symptom for both tests, we observed different physiological responses.

Exercise performance and differences in physiological response to pulmonary rehabilitation in severe chronic obstructive pulmonary disease with hyperinflation

Objective:

Pulmonary rehabilitation (PR) improves exercise capacity in most but not all COPD patients. The factors associated with treatment success and the role of chest wall mechanics remain unclear. We investigated the impact of PR on exercise performance in COPD with severe hyperinflation.

Methods:

We evaluated 22 COPD patients (age, 66 ± 7 years; FEV₁ = 37.1 ± 11.8% of predicted) who underwent eight weeks of aerobic exercise and strength training. Before and after PR, each patient also performed a six-minute walk test and an incremental cycle ergometer test. During the latter, we measured chest wall volumes (total and compartmental, by optoelectronic plethysmography) and determined maximal workloads.

Results:

We observed significant differences between the pre- and post-PR means for six-minute walk distance (305 ± 78 vs. 330 ± 96 m, p < 0.001) and maximal workload (33 ± 21 vs. 39 ± 20 W; p = 0.02). At equivalent workload settings, PR led to lower oxygen consumption, carbon dioxide production (VCO₂), and minute ventilation. The inspiratory (operating) rib cage volume decreased significantly after PR. There were 6 patients in whom PR did not increase the maximal workload. After PR, those patients showed no significant decrease in VCO₂ during exercise, had higher end-expiratory chest wall volumes with a more rapid shallow breathing pattern, and continued to experience symptomatic leg fatigue.

Conclusions:

In severe COPD, PR appears to improve oxygen consumption and reduce VCO₂, with a commensurate decrease in respiratory drive, changes reflected in the operating chest wall volumes. Patients with severe post-exercise hyperinflation and leg fatigue might be unable to improve their maximal performance despite completing a PR program.

Comparing Various Exercise Tests for Assessing the Response to Pulmonary Rehabilitation in Patients With COPD

PURPOSE

Various exercise tests have been used to assess the response to pulmonary rehabilitation (PR) in patients with chronic obstructive pulmonary disease (COPD). Few studies have compared exercise tests in the same subjects to determine the relative responsiveness of various tests. The goal of this pilot study was to examine the responsiveness of different exercise tests in patients with COPD completing PR.

METHODS

Fifteen male patients with COPD underwent PR. All subjects completed 6-minute walk test (6MWT), incremental shuttle walk test (ISWT), endurance shuttle walk test (ESWT), maximal incremental exercise test (MIET), constant workload exercise test (CWET), and maximal arm ergometry tests before and after PR. The Chronic Respiratory Disease Questionnaire was also completed before and after PR.

RESULTS

The number of participants who exceeded the minimal clinically important difference was similar for each of the different exercise tests. Effect sizes for the MIET and CWET were slightly higher, 0.82 and 0.97, respectively, than for the 6MWT, ISWT, and ESWT, 0.72, 0.65, and 0.60, respectively. Effect sizes were not significantly different between the 6MWT and the ESWT. The changes in exercise test results were not significantly correlated with the changes in quality of life. The improvement in laboratory cycling tests did not significantly correlate with the improvement in shuttle walk tests.

CONCLUSIONS

On the basis of these data, all exercise measures were responsive to PR. Indices derived from cycling in the laboratory appeared more responsive than indices derived from walking in the field when assessed by effect size, but this finding and its possible clinical significance requires confirmation in a larger study.

The Effect of Fatigue and Fatigue Intensity on Exercise Tolerance in Moderate COPD

INTRODUCTION

Fatigue is one of the most disabling symptoms in COPD, but little is known about the impact of fatigue on functional disability. We explored the impact of fatigue and fatigue intensity on exercise tolerance after adjusting for other factors using multivariate analysis and compared it to that of dyspnoea.

METHODS

A total of 119 patients with mainly moderate-severe stable COPD (38 % women, mean age 66 years) were enrolled. We used the Medical Research Council dyspnoea scores (MRC), Manchester COPD fatigue scale (MCFS) and its three dimensions, Borg scales for fatigue and dyspnoea, six-minute walk distance (6MWD), St George's Respiratory Questionnaire, the BODE index, and the Centre for Epidemiological Study on Depression scale (CES-D), and we measured spirometry, blood gases, systemic inflammatory markers and fat-free mass index (FFMI).

RESULTS

Fatigue measured using the MCFS was associated with 6MWD and explained 22 % of the variability in 6MWD (p < 0.001). Fatigue remained associated with 6MWD after adjusting for MRC dyspnoea, FFMI and FEV1, FVC, PaO2, PaCO2, CES-D, TNF-alpha, smoking status, age and gender. We found that 33, 50 and 23 % of patients reported an increase by 2 scores on Borg scales for fatigue, dyspnoea or both at the end of the 6MWT. Fatigue scores (both before and after the 6MWT) were negatively correlated with 6MWD after adjusting for FEV1, FFMI, CES-D score and age (p = 0.007 and 0.001, respectively).

CONCLUSION

In moderate stable COPD, fatigue may be a central driver of functional disability, to the same extent as dyspnoea.

Comparison of the six-minute walk test with a cycle-based cardiopulmonary exercise test in people following curative intent treatment for non-small cell lung cancer

This study is aimed to (i) compare both the magnitude of impairment in exercise capacity and exercise responses measured during the six-minute walk test (6MWT) and the cardiopulmonary exercise test (CPET) and (ii) investigate the effect of test repetition on six-minute walk distance (6MWD) in people following curative intent treatment for non-small cell lung cancer (NSCLC). Twenty participants (67 ± 10 years; 14 females), 6-10 weeks following lobectomy, underwent a CPET and two 6MWTs. Peak exercise responses, dyspnoea and leg fatigue, as well as heart rate (HR) and oxygen saturation (SpO2) during the 6MWT, were compared to those during the CPET. Compared with exercise capacity when expressed as peak rate of oxygen consumption (%pred) measured during the CPET, exercise capacity when expressed as 6MWD (%pred) was less impaired (81 ± 10 vs. 63 ± 15 %pred; p < 0.001). Compared with the CPET, the 6MWT elicited lower peak HR (119 ± 15 vs. 128 ± 18 beats minute(-1); p = 0.02), lower SpO2 (93 ± 2 vs. 95 ± 3%; p < 0.05), less dyspnoea (3.1 ± 1.6 vs. 6.9 ± 2.6; p < 0.01) and less leg fatigue (2.0 ± 1.9 vs. 6.8 ± 2.4; p < 0.01). The 6MWD increased 19 ± 19 metre (4 ± 4%) with test repetition (p < 0.001). In people following curative intent treatment for NSCLC, the 6MWT appears to elicit sub-maximal exercise responses when compared with the CPET. There is a significant effect of test repetition on 6MWD.

Characterisation of fatigue and its substantial impact on health status in a large cohort of patients with chronic pulmonary aspergillosis (CPA)

INTRODUCTION

Fatigue is a prominent disabling symptom in several pulmonary diseases. Its impact on health status in patients with chronic pulmonary aspergillosis (CPA) has not been investigated.

METHODS

A total of 151 CPA patients attending the National Aspergillosis Centre completed Manchester COPD Fatigue Scale (MCFS), St. George's Respiratory Questionnaire (SGRQ) and Medical Research Council (MRC) dyspnoea score. Lung function and BMI were measured. Univariate, multivariate linear and binary analyses, and principal component analysis (PCA) were used.

RESULTS

Female patients accounted for 44%. The mean (range) of age was 59.6 (31-83) years, FEV1% was 64 (14-140), BMI was 23.6 (16.3-43.4), SGRQ total score was 56 (4-96.2) and MCFS total score was 30.6 (0-54). PCA showed that 27 items of MCFS loaded on three components; physical, psychosocial and cognitive fatigue, explaining 78.4% of fatigue variance. MCFS score correlated strongly with total SGRQ score (r = 0.83, p < 0.001). Using linear multivariate analysis, fatigue was the strongest factor (beta = 0.7 p < 0.0001) associated with impaired health status, after adjusting for age, BMI, FEV1%, and MRC dyspnoea score. Using patients' 5 self-assessment grades of their health, one-way ANOVA showed that those with "very poor" health status had the highest fatigue scores (45 (±6) (p < 0.001)). Logistic regression analysis showed that fatigue score (OR = 0.9, 95% CI 0.84-0.97; p = 0.005) and FEV1% (OR = 1.03, 95% CI 1.01-1.07, p = 0.02) are significantly associated with self-assessed impaired health status after correcting for age, gender and DLCO%.

CONCLUSION

Fatigue is a major component of impaired health status of CPA patients.

Pulmonary rehabilitation in lymphangioleiomyomatosis: a controlled clinical trial

Lymphangioleiomyomatosis (LAM) is a cystic lung disease frequently associated with reduced exercise capacity. The aim of this study was to assess safety and efficacy of pulmonary rehabilitation in LAM.This controlled clinical trial included 40 patients with LAM and a low physical activity level. The pulmonary rehabilitation programme comprised 24 aerobic and muscle strength training sessions and education. The primary outcome was exercise capacity (endurance time during a constant work rate exercise test). Secondary outcomes included health-related quality of life (St George's Respiratory Questionnaire (SGRQ)), 6-min walking distance (6MWD), dyspnoea, peak oxygen consumption (V'O2 ), daily physical activity (pedometer), symptoms of anxiety and depression, lung function and peripheral muscle strength (one-repetition maximum).The baseline characteristics were well balanced between the groups. The pulmonary rehabilitation group exhibited improvements in the following outcomes versus controls: endurance time (median (interquartile range) 169 (2-303) s versus -33 (-129-39) s; p=0.001), SGRQ (median (interquartile range) -8 (-16-2) versus 2 (-4-5); p=0.002) and 6MWD (median (interquartile range) 59 (13-81) m versus 20 (-12-30) m; p=0.002). Dyspnoea, peak V'O2 , daily physical activity and muscle strength also improved significantly. No serious adverse events were observed.Pulmonary rehabilitation is a safe intervention and improves exercise capacity, dyspnoea, daily physical activity, quality of life and muscle strength in LAM.

Neuromuscular electrical stimulation to improve exercise capacity in patients with severe COPD: a randomised double-blind, placebo-controlled trial

BACKGROUND

Skeletal muscle dysfunction and exercise intolerance are common in severe chronic obstructive pulmonary disease (COPD). We assessed the effectiveness of neuromuscular electrical stimulation (NMES) as a home-based exercise therapy.

METHODS

In this double-blind, placebo-controlled trial, undertaken across three UK National Health Service sites, we randomly assigned (1:1) adults with COPD, a forced expiratory volume in 1 s (FEV1) less than 50% predicted, and incapacitating breathlessness (Medical Research Council dyspnoea scale ≥4) to receive active or placebo NMES, daily over a 6-week period. Randomisation was by an independent system using minimisation to balance age, GOLD stage, and quadriceps strength. Participants and outcome assessors were masked to group allocation. The primary endpoint was change in 6-min walk test (6MWT) distance at 6 weeks. Analysis was by intention to treat. The trial was registered as ISRCTN15985261 and is now closed.

FINDINGS

Between June 29, 2012, and July 4, 2014, we enrolled 73 participants, of whom 52 participants were randomly assigned; 25 to receive active NMES and 27 to placebo NMES. Change in 6MWT distance was greater in the active NMES group (mean 29·9 [95% CI 8·9 to 51·0]) compared with in the placebo group (-5·7 [-19·9 to 8·4]; mean difference at 6 weeks 35·7 m [95% CI 10·5 to 60·9]; p=0·005). Sensitivity analyses for complete-cases and adjustment for baseline values showed similar results. 6 weeks after stopping the intervention the effect waned (7·3 m [95% CI -32·5 to 47·0]; p=0·50). The proportion of participants who had adverse events was similar between groups (five [20%] in the active NMES group and nine [33%] in the placebo group). Two participants, one from each group, reported persistent erythema, which was considered to be possibly related to NMES and the use of adhesive electrodes.

INTERPRETATION

NMES improves functional exercise capacity in patients with severe COPD by enhancing quadriceps muscle mass and function. These data support the use of NMES in the management of patients unable to engage with conventional pulmonary rehabilitation. More work is needed to study how to maintain the effect.

FUNDING

National Institute for Health Research.

Effect of 6-minute walk test on neuromuscular properties of patients with chronic obstructive pulmonary disease

OBJECTIVE

The objective of this study was to evaluate the neuromechanical properties of the knee extensor muscles before and after the 6-minute walk test (6MWT) in chronic obstructive pulmonary disease (COPD) patients and control subjects.

MATERIALS AND METHODS

COPD patients from the Department of Pulmonology of the Hospital de Clinicas de Porto Alegre and age- and sex-matched control volunteers without COPD were included in this study. Body composition and lower limb strength assessed by maximal voluntary isometric contraction (MVIC) of the knee extensors) were assessed before and after the 6MWT. The total reaction time (TRT), premotor time (PMT) and motor time (MT) were assessed using surface electromyography of the rectus femoris and vastus lateralis knee extensor muscles.

RESULTS

Eighteen patients COPD patients (10 men, FEV₁ 36 ± 12% of predicted) and 8 control subjects (5 men, FEV₁ 82 ± 7% of predicted) were included. COPD patients had lower muscle strength before (21.77 ± 7.86 kg) and after the 6MWT (11.16 ± 4.70 kg) compared with control subjects (33.50 ± 14.01 kg before; 29.25 ± 16.66 kg after). After the 6MWT, COPD patients showed a significant reduction in the MVIC and a significant increase in the TRT and PMT, which did not occur in control subjects. The reaction time parameters were higher in COPD patients after the 6MWT compared with control subjects. The TRT (r = -0.535, P < 0.005) and PMT (r = -0.549, P < 0.005) were inversely correlated with the MVIC after the 6MWT.

CONCLUSIONS

Neuromuscular changes associated with upper motor neuron activation contribute to MVIC impairment in COPD patients after performing a functional test.

Benefits of Physical Training in Sarcoidosis

BACKGROUND

Sarcoidosis patients suffer from fatigue and exercise limitation. The aim of this study was to establish whether a physical training program improves these and other outcomes important to sarcoidosis patients.

METHODS

From 11/2012 to 9/2014, 201 sarcoidosis patients were referred to the ild care expertise team, Ede, the Netherlands. In our center, all patients are routinely recommended to undergo testing at baseline to determine their physical functioning and encouraged to complete a 12-week, supervised physical training program. Ninety patients underwent baseline testing and returned for repeat testing at 3 months in the interim, 49 completed the training program (Group I) and 41 chose not to participate (Group II). Change over time (from baseline to 3 months) in fatigue, exercise capacity, and skeletal muscle strength were assessed between the two groups.

RESULTS

At baseline, there were no between-group differences for fatigue, DLCO%, FVC%, or exercise capacity [assessed by percent predicted six-minute walk distance (6MWD%) and Steep Ramp Test (SRT)]. The 6MWD for Group I improved between baseline and 3 months, while the 6MWD remained the same in Group II (F = 72.2, p < 0.001). Group I showed a significantly larger decrease of fatigue compared with Group II (F = 6.27, p = 0.014). Lung function tests did not change in either group.

CONCLUSION

A supervised physical training program improves exercise capacity and fatigue among sarcoidosis patients and should be included in their management regimen.

Guidelines for the evaluation and treatment of muscle dysfunction in patients with chronic obstructive pulmonary disease

In patients with chronic obstructive pulmonary disease (COPD), skeletal muscle dysfunction is a major comorbidity that negatively impacts their exercise capacity and quality of life. In the current guidelines, the most recent literature on the various aspects of COPD muscle dysfunction has been included. The Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) scale has been used to make evidence-based recommendations on the different features. Compared to a control population, one third of COPD patients exhibited a 25% decline in quadriceps muscle strength, even at early stages of their disease. Although both respiratory and limb muscles are altered, the latter are usually more severely affected. Numerous factors and biological mechanisms are involved in the etiology of COPD muscle dysfunction. Several tests are proposed in order to diagnose and evaluate the degree of muscle dysfunction of both respiratory and limb muscles (peripheral), as well as to identify the patients' exercise capacity (six-minute walking test and cycloergometry). Currently available therapeutic strategies including the different training modalities and pharmacological and nutritional support are also described.

Muscular and functional effects of partitioning exercising muscle mass in patients with chronic obstructive pulmonary disease - a study protocol for a randomized controlled trial

BACKGROUND

Low-load, high-repetitive single-limb resistance training may increase limb muscle function and functional exercise capacity in patients with chronic obstructive pulmonary disease (COPD) while minimizing the occurrence of limiting exertional symptoms. Whether high-repetitive single-limb resistance training would perform better than high-repetitive two-limb resistance training is unknown. In addition, the mechanisms underlying possible benefits of high-repetitive resistance training has not been investigated. The aims of this study are to compare single versus two-limb high-repetitive resistance training in patients with COPD and to investigate mechanisms of action of these training modalities.

METHODS/DESIGN

This trial is a prospective, assessor-blind, randomized controlled trial. The participants are patients with stable severe to very severe COPD who are older than 40 years of age and healthy controls. The intervention is single-limb, high-repetitive, resistance training with elastic bands, three times/week for 8 weeks. The control is two-limb high-repetitive resistance training with elastic bands, three times/week for 8 weeks. The primary outcomes is change in the 6-min walking distance after 8 weeks of single-limb or two-limb high-repetitive resistance training. The secondary outcomes are changes in limb muscle strength and endurance capacity, key protein involved in quadriceps anabolic/catabolic signalization, fiber-type distribution and capillarization, subjective dyspnea and muscle fatigue, muscle oxygenation, cardiorespiratory demand and health-related quality-of-life after 8 weeks of single-limb or two-limb high-repetitive resistance training. The acute effects of single-limb versus two-limb high-repetitive resistance training on contractile fatigue, exercise stimulus (the product of number of repetition and load), subjective dyspnea and muscle fatigue, muscle oxygenation, and cardiorespiratory demand during upper and lower limb exercises will also be investigated in patients with COPD and healthy controls. Randomization will be performed using a random number generator by a person independent of the recruitment process, using 1:1 allocation to the intervention and the control group using random block sizes.

BLINDING

All outcome assessors will be blinded to group assignment.

DISCUSSION

The results of this project will provide important information to help developing and implementing customized exercise training programs for patients with COPD.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier NCT02283580 Registration date: 4 November 2014. First participant randomized: 10 November 2014.

Physiological responses during downhill walking

Skeletal muscle quadriceps low-frequency fatigue (LFF) during exercise promotes improvements in exercise capacity with exercise training. In healthy subjects, eccentric muscle work induced by downhill walking (DW) generates higher muscular stress, whilst metabolic cost is lower compared to level walking (LW). We investigated quadriceps LFF and metabolic cost of DW in patients with chronic obstructive pulmonary disease. Ten participants (67 ± 7 years, FEV1 51 ± 15% predicted) performed DW, DW carrying a load (DWL) of 10% body weight via vest and LW, in random order. Quadriceps potentiated twitch force (TWqpot) was assessed before and after each walk, and muscle damage was assessed before and 24 hours after each walk via serum creatine kinase (CK) levels. Ventilation (VE) and oxygen consumption (VO2) were measured via breath-by-breath analysis during each walk. DW and DWL resulted in a greater decrease in TWqpot (−30 ± 14 N in DW, p < 0.05; and −22 ± 16 N in DWL, p < 0.05) compared to LW (−3 ± 21 N, p > 0.05). CK levels only increased 24 hours following DW and DWL ( p < 0.05). DW and DWL showed lower VE and VO2 than LW ( p < 0.05). DW is associated with enhanced quadriceps LFF and lower cardiorespiratory costs than LW. The addition of a chest load to DW does not seem to enhance these effects.

Contractile fatigue of the quadriceps muscle predicts improvement in exercise performance after pulmonary rehabilitation

RATIONALE

We hypothesized that among patients with chronic obstructive pulmonary disease, those who develop quadriceps contractile fatigue (QCF) after exhaustive submaximal cycle exercise would have a greater response to exercise training than those who do not develop QCF (NQCF).

METHODS

Patients (N = 132) had measurement of QCF at baseline. Six-minute walk distance (6 MWD), maximal incremental cycle exercise testing, and quality of life measured by the Chronic Respiratory Questionnaire were obtained before and after pulmonary rehabilitation (PR).

RESULTS

Eighty of the 132 patients (60.6%) developed QCF following constant workload exhaustive cycle exercise. Patients who developed QCF had a significantly greater improvement in 6 MWD following PR (45.3 ± 45.2 m) than those who did not (27.5 ± 45.7 m; P= .032). When baseline differences between patients who developed QCF and NQCF were accounted for, the difference in 6 MWD remained significant. Patients who developed QCF were not more likely to identify leg fatigue as the factor limiting exercise (56.2% of QCF group stated that leg fatigue was the limiting factor compared with 47.9% in the NQCF group; P= .46). When baseline differences were accounted for, the symptom causing exercise termination was not a predictor of the response to PR.

CONCLUSION

Patients who were capable of developing QCF had a significantly greater improvement in 6 MWD after PR compared to NQCF. Symptoms causing exercise termination could not be used to predict the development of contractile fatigue or the response to PR.