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Exercise & Sports Science Australia (ESSA) position statement on exercise and chronic obstructive pulmonary disease

  • Norman. R. Morris
    Correspondence
    Corresponding author.
    Affiliations
    School of Allied Health Sciences, Griffith University, Australia

    Metro North Hospital and Health Service, The Prince Charles Hospital. Allied Health Research Collaborative, Australia

    Menzies Health Institute, Griffith University, Australia

    Queensland Lung Transplant Service, The Prince Charles Hospital, Australia
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  • Kylie Hill
    Affiliations
    School of Physiotherapy and Exercise Science, Curtin University, Australia
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  • James Walsh
    Affiliations
    School of Allied Health Sciences, Griffith University, Australia

    Queensland Lung Transplant Service, The Prince Charles Hospital, Australia
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  • Surendran Sabapathy
    Affiliations
    School of Allied Health Sciences, Griffith University, Australia

    Metro North Hospital and Health Service, The Prince Charles Hospital. Allied Health Research Collaborative, Australia

    Menzies Health Institute, Griffith University, Australia
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Published:August 31, 2020DOI:https://doi.org/10.1016/j.jsams.2020.08.007

      Abstract

      Objectives

      Chronic obstructive pulmonary disease (COPD) results in airflow obstruction and a marked reduction in exercise capacity and health-related quality of life (HRQoL). Affecting over 1 in four Australians aged over 75 years, COPD remains one of the major causes of disability and death in the world. To date there have been over 80 randomised controlled trials examining the role of exercise training in a range of settings for individuals with COPD. This review will synthesise existing literature and provide health practitioners with broad evidence-based guidelines for exercise-training in this growing population.

      Design

      Position stand.

      Methods

      Synthesis of randomised controlled trials of exercise training and of existing guidelines for exercise in COPD. Systematic reviews of alternative modes of exercise training will also be reviewed.

      Results

      There is convincing evidence that in adults with COPD, exercise-training improves exercise capacity, decreases symptoms such as dyspnoea and fatigue, and improves HRQoL. There is emerging evidence in this population that alternative modes of exercise training such as high intensity interval training (HIIT), aquatic based therapy, tai chi and neuromuscular electrical stimulation improve exercise outcomes when compared to no exercise.

      Conclusions

      For individuals with COPD, an exercise program of aerobic and strength exercises delivered over at least an 8-week period, that engages lower and upper body skeletal muscles, will deliver significant health improvements. Programs should be individualised, take into consideration relevant co-morbid conditions and be delivered appropriately qualified health practitioners experienced in clinical exercise prescription.

      Keywords

      1. Background

      Chronic obstructive pulmonary disease (COPD) is characterised by airflow obstruction that is not fully reversible
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      and an abnormal inflammatory response of the lungs.
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      Airflow obstruction is the result of changes in the airways and parenchyma associated with emphysema and chronic bronchitis.
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      Inflammation in chronic obstructive pulmonary disease and its role in cardiovascular disease and lung cancer.
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      ABC of chronic obstructive pulmonary disease. Pathology, pathogensis and pathophysiology.
      The emphysematous changes result in the destruction of alveolar walls and their attachments, compromising the patency of the airways and leading to airflow obstruction. The accompanying enlargement of the air spaces of the lung distal to the terminal bronchiole also reduce the area available for gas exchange. Chronic bronchitis is a hyper-secretory disorder characterised by excessive production and secretion of mucus within the bronchial tree. Additionally, chronic inflammation in the small airways leads to injury of the airway wall. The injury-repair cycle consequently results in structural remodelling of the airway walls and increased scar tissue and collagen formation, thus narrowing the airway lumen and causing “fixed” airway obstruction.
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      Pulmonary Pathophysiology: The Essentials.
      In 2020, COPD is estimated to be the third-leading cause of death worldwide and is a major cause of lost disability adjusted life years.
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      • Criner G.J.
      • Martinez F.J.
      • et al.
      Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease 2017 Report. GOLD Executive Summary.
      In Australia, 7.5% of individuals aged over 40 years are affected by COPD that is at least of moderate severity, with the prevalence increasing with age (29% prevalence in adults aged >75 years).
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      • Xuan W.
      • Bird T.E.
      • et al.
      Respiratory symptoms and illness in older Australians: the Burden of Obstructive Lung Disease (BOLD) study.
      The risks for developing COPD encompass host factors and environmental exposures, and development of the disease is usually attributable to a combination of both. Host factors that exclusively contribute to COPD (e.g. α1-antitrypsin deficiency) are rare (less than 1%
      • McGrady T.
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      • Malanga E.
      • et al.
      Characteristics of Chronic Obstructive Pulmonary Disease (COPD) Patients Reporting Alpha-1 Antitrypsin Deficiency in the WebMD Lung Health Check Database.
      ). Thus, COPD is typically associated with environmental exposure to noxious particles and gases. Cigarette smoke is the primary risk factor, with 20-25% of smokers developing COPD.
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      • Lindberg A.
      • Lindstrom M.
      • et al.
      Not 15 but 50% of smokers develop COPD?–Report from the Obstructive Lung Disease in Northern Sweden Studies.
      Cardinal symptoms of COPD include shortness of breath (dyspnoea), particularly on exertion, chronic cough and excess sputum production. Diagnosis is established through spirometry,
      • Vogelmeier C.F.
      • Criner G.J.
      • Martinez F.J.
      • et al.
      Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease 2017 Report. GOLD Executive Summary.
      with a post-bronchodilator forced expired volume in one second (FEV1) and forced vital capacity (FVC) ratio (FEV1/FVC) of less than 0.7 confirming the presence of persistent airflow obstruction.
      • Vogelmeier C.F.
      • Criner G.J.
      • Martinez F.J.
      • et al.
      Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease 2017 Report. GOLD Executive Summary.
      Extrapulmonary symptoms such as cachexia (muscle wasting) and anaemia may occur, due at least in part to the systemic inflammatory response.
      • Choudhury G.
      • Rabinovich R.
      • MacNee W.
      Comorbidities and systemic effects of chronic obstructive pulmonary disease.
      There is no cure for COPD; however, the recently updated COPD plan (COPD-X) provided by the Lung Foundation Australia provides an evidence-based stepwise plan for multidisciplinary management.
      • Yang I.A.
      • Brown J.L.
      • George J.
      • et al.
      COPD-X Australian and New Zealand guidelines for the diagnosis and management of chronic obstructive pulmonary disease: 2017 update.
      Management of COPD primarily entails smoking cessation and removal or modification of risk factors. Symptom reduction and exacerbation risk minimisation is also provided through short- and long-acting bronchodilator therapy (short and long acting beta agonists [SABA and LABA]; short and long acting antimuscarinics [SAMA and LAMA]) which, when combined with inhaled corticosteroids (ICS) are known as preventers. During an exacerbation, oral glucocorticosteroid may be prescribed. Referral for exercise training, typically to a pulmonary rehabilitation program, is also recommended for individuals with symptoms that limit participation in activities of daily living.
      • Yang I.A.
      • Brown J.L.
      • George J.
      • et al.
      COPD-X Australian and New Zealand guidelines for the diagnosis and management of chronic obstructive pulmonary disease: 2017 update.
      • Spruit M.A.
      • Singh S.J.
      • Garvey C.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: key concepts and advances in pulmonary rehabilitation.

      2. Exercise intolerance and disability in COPD

      Individuals with COPD have reduced exercise capacity and poor health-rated quality of life (HRQoL).
      • Yang I.A.
      • Brown J.L.
      • George J.
      • et al.
      COPD-X Australian and New Zealand guidelines for the diagnosis and management of chronic obstructive pulmonary disease: 2017 update.
      The progressive nature of the disease results in increased dyspnoea on exertion, leading to a vicious cycle of inactivity and deconditioning. Physical activity levels are markedly reduced.
      • Watz H.
      • Waschki B.
      • Meyer T.
      • et al.
      Physical activity in patients with COPD.
      The gradual deterioration in exercise capacity may be accompanied by psychosocial issues such as social isolation, depression, anxiety, and loss of independence, that exert an increasingly deleterious effect upon HRQoL.
      • Vogelmeier C.F.
      • Criner G.J.
      • Martinez F.J.
      • et al.
      Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Lung Disease 2017 Report. GOLD Executive Summary.
      • Atlantis E.
      • Fahey P.
      • Cochrane B.
      • et al.
      Bidirectional associations between clinically relevant depression or anxiety and COPD: a systematic review and meta-analysis.
      The systemic inflammation contributes to extrapulmonary manifestations and comorbid conditions such as cardiovascular disease, lung cancer and skeletal muscle dysfunction.
      • King P.T.
      Inflammation in chronic obstructive pulmonary disease and its role in cardiovascular disease and lung cancer.
      • Choudhury G.
      • Rabinovich R.
      • MacNee W.
      Comorbidities and systemic effects of chronic obstructive pulmonary disease.
      • Agusti A.G.
      • Noguera A.
      • Sauleda J.
      • et al.
      Systemic effects of chronic obstructive pulmonary disease.
      • Maltais F.
      • Decramer M.
      • Casaburi R.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: update on limb muscle dysfunction in chronic obstructive pulmonary disease.
      Both ventilatory limitation and skeletal muscle dysfunction contribute to the increased exertional dyspnoea and reduced exercise capacity.
      • Maltais F.
      • Decramer M.
      • Casaburi R.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: update on limb muscle dysfunction in chronic obstructive pulmonary disease.
      • Langer D.
      • Ciavaglia C.E.
      • Neder J.A.
      • et al.
      Lung hyperinflation in chronic obstructive pulmonary disease: mechanisms, clinical implications and treatment.
      Cardiovascular limitations, nutritional deficiencies, and psychological factors may also play a role in the reduction in exercise capacity.
      • Atlantis E.
      • Fahey P.
      • Cochrane B.
      • et al.
      Bidirectional associations between clinically relevant depression or anxiety and COPD: a systematic review and meta-analysis.
      • Agusti A.G.
      • Noguera A.
      • Sauleda J.
      • et al.
      Systemic effects of chronic obstructive pulmonary disease.

      3. Ventilatory limitation

      Individuals with COPD are ventilatory limited, typically due to expiratory airflow limitation.
      • Laveneziana P.
      • Parker C.M.
      • O’Donnell D.E.
      Ventilatory constraints and dyspnea during exercise in chronic obstructive pulmonary disease.
      • O’Donnell D.E.
      • Ora J.
      • Webb K.A.
      • et al.
      Mechanisms of activity-related dyspnea in pulmonary diseases.
      Gas trapping at rest and further gas trapping during exercise results in increased end-expiratory lung volumes on exertion (dynamic hyperinflation).
      • Laveneziana P.
      • Parker C.M.
      • O’Donnell D.E.
      Ventilatory constraints and dyspnea during exercise in chronic obstructive pulmonary disease.
      • O’Donnell D.E.
      • Ora J.
      • Webb K.A.
      • et al.
      Mechanisms of activity-related dyspnea in pulmonary diseases.
      As a result, many individuals with COPD breathe at higher operational lung volumes, placing elastic and threshold loads on the inspiratory muscles.
      • Maltais F.
      • Decramer M.
      • Casaburi R.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: update on limb muscle dysfunction in chronic obstructive pulmonary disease.
      • Laveneziana P.
      • Parker C.M.
      • O’Donnell D.E.
      Ventilatory constraints and dyspnea during exercise in chronic obstructive pulmonary disease.
      • O’Donnell D.E.
      • Ora J.
      • Webb K.A.
      • et al.
      Mechanisms of activity-related dyspnea in pulmonary diseases.
      Tidal volume expansion is limited, meaning that ventilation is increased primarily through increased breathing frequency. Gas exchange abnormalities can also contribute to ventilatory limitation. Excess physiological dead space, intrapulmonary shunting, ventilation to perfusion mismatch and impaired lung diffusion capacity contribute to hypoxaemia, hypercapnia, and an increased ventilatory demand for a given level of physical activity.
      • West J.B.
      Pulmonary Pathophysiology: The Essentials.
      Hypoxic vasoconstriction and structural remodelling of the pulmonary vasculature may also increase pulmonary vascular resistance and right ventricular afterload, while dynamic lung hyperinflation may impair right ventricular preload and limit cardiac output during exercise.
      • Laveneziana P.
      • Parker C.M.
      • O’Donnell D.E.
      Ventilatory constraints and dyspnea during exercise in chronic obstructive pulmonary disease.

      3.1 Skeletal muscle dysfunction

      It is now well-recognised that changes in peripheral skeletal muscle function contribute to the disability associated with the COPD.
      • Maltais F.
      • Decramer M.
      • Casaburi R.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: update on limb muscle dysfunction in chronic obstructive pulmonary disease.
      Lower limb fatigue and discomfort are important contributing factors to exercise intolerance in people with COPD.
      • Killian K.J.
      • Leblanc P.
      • Martin D.H.
      • et al.
      Exercise capacity and ventilatory, circulatory, and symptom limitation in patients with chronic airflow limitation.
      Studies have shown muscle fibre atrophy, changes in fibre composition with a selective loss of type I fibres,
      • Bernard S.
      • LeBlanc P.
      • Whittom F.
      • et al.
      Peripheral muscle weakness in patients with chronic obstructive pulmonary disease.
      • Whittom F.
      • Jobin J.
      • Simard P.M.
      • et al.
      Histochemical and morphological characteristics of the vastus lateralis muscle in patients with chronic obstructive pulmonary disease.
      reduced capillary to fibre ratio,
      • Whittom F.
      • Jobin J.
      • Simard P.M.
      • et al.
      Histochemical and morphological characteristics of the vastus lateralis muscle in patients with chronic obstructive pulmonary disease.
      and a reduction in oxidative enzyme activity
      • Maltais F.
      • Simard A.A.
      • Simard C.
      • et al.
      Oxidative capacity of the skeletal muscle and lactic acid kinetics during exercise in normal subjects and in patients with COPD.
      of skeletal muscle in people with COPD. These changes contribute to an early reliance on anaerobic metabolism during exercise resulting in an early onset of lactic acidosis, a greater non-metabolic carbon dioxide production and excessive ventilatory response,
      • Maltais F.
      • Decramer M.
      • Casaburi R.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: update on limb muscle dysfunction in chronic obstructive pulmonary disease.
      which further contributes to the ventilatory limitation in COPD.

      4. THE ROLE OF EXERCISE TRAINING IN THE MANAGEMENT OF COPD

      Therapeutic exercise, delivered through an exercise-based rehabilitation program such as pulmonary rehabilitation, is recognised as an essential component of the management of people with COPD with convincing evidence that it improves exercise capacity, decreases symptoms such as dyspnoea and fatigue, and improves HRQoL.
      • McCarthy B.
      • Casey D.
      • Devane D.
      • et al.
      Pulmonary rehabilitation for chronic obstructive pulmonary disease.
      • Yang Q.
      • Underwood M.J.
      • Hsin M.K.Y.
      • et al.
      Dysfunction of pulmonary vascular endothelium in chronic obstructive pulmonary disease: Basic considerations for future drug development.
      The average magnitude of change in these outcomes exceeds the threshold for the minimal clinical important difference. Moreover, there is evidence that well implemented exercise-based rehabilitation programs, embedded into comprehensive pulmonary rehabilitation, result in reduced hospitalisations and long-term health economic benefits.
      • Alison J.A.
      • McKeough Z.J.
      • Johnston K.
      • et al.
      Australian and New Zealand Pulmonary Rehabilitation Guidelines.
      • Rochester C.L.
      • Vogiatzis I.
      • Holland A.E.
      • et al.
      An Official American Thoracic Society/European Respiratory Society Policy Statement: Enhancing Implementation, Use, and Delivery of Pulmonary Rehabilitation.
      A summary of the RCTs examining exercise-based rehabilitation is shown in Table 1. A more detailed summary of these RCTs is included in Supplementary Table. The primary source for this Table are the 65 RCTs from the recent Cochrane review by McCarthy et al
      • McCarthy B.
      • Casey D.
      • Devane D.
      • et al.
      Pulmonary rehabilitation for chronic obstructive pulmonary disease.
      (which has now closed) and an additional search using the same search terms and inclusion criteria as the Cochrane review date (26th March, 2014) up until March, 2019. This search yielded an additional 1364 articles which, following a title, abstract and article review, resulted in a further 20 studies (see Supplementary Table).
      Table 1Summary of exercise training doses reported in randomised controlled trials of exercise training in people with chronic obstructive pulmonary disease.
      Number of StudiesNMean Age

      (yr)
      Mean FEV1

      (%)
      SettingModeMeasures used to prescribe exercise intensityFrequency (days/wk)Duration (min)Length

      (wk)
      Measures used to evaluate program
      854,50265 ± 4

      (52 to 77)
      46 ± 13

      (27 to 90)
      IP/OP/

      Comm/

      Home
      ULT; LLT; IMT; STRWpeak; %VO2peak; RPE; modified BORG; 6MWT speed; ISWT speed; RM3.2 ± 1.6

      (1 to 7)
      55 ± 24

      (30 to 120)
      14

      (4 to 52)
      6MWT; HRQoL; Wpeak, VO2peak
      Data for age, FEV1(%), frequency, duration and length are presented as mean ± standard deviation of the mean. Data in brackets represent the range (minimum to maximum).
      N: Number.
      Age: mean age in years (yr), combined control and exercise groups.
      FEV1 (%): mean forced expiratory volume in one second percentage predicted combined control and exercise groups.
      Setting: site at which exercise program conducted. IP: inpatient; OP: outpatient; Comm: community; Home: home based.
      Mode: mode of exercise training. ULT: upper limb training; LLT: lower limb training; IMT: inspiratory muscle training; STR: strength training.
      Measures used to prescribe exercise intensity: Wpeak: peak power on cycle ergometer; VO2peak: peak rate of oxygen consumption; RPE: rating of perceived exertion; modified BORG: 0-10 breathlessness scale; 6MWT: six minute walk test; CPET: cardiopulmonary exercise test; ISWT: incremental shuttle walk test; RM repetition maximum.
      Frequency: number of days per week of exercise training.
      Duration: duration of each session in minutes.
      Length: length of program in weeks.
      Measures used to evaluate program: 6MWT: six minute walk test; HRQoL: health-related quality of life; Wpeak: peak power on cycle ergometer; VO2peak: peak rate of oxygen consumption.

      5. Alternative and adjuncts to ‘traditional’ exercise training programs

      5.1 High intensity interval training

      There has been a reasonably large body of work examining the role of high intensity interval exercise (HIIT) training in COPD.
      • Morris N.R.
      • Walsh J.
      • Adams L.
      • et al.
      Exercise training in COPD: What is it about intensity?.
      • Zainuldin R.
      • Mackey M.G.
      • Alison J.A.
      Optimal intensity and type of leg exercise training for people with chronic obstructive pulmonary disease.
      This type of training is predominantly undertaken on a cycle ergometer whereby repeat short bouts of exercise, prescribed at intensities at or near Wpeak, are separated by periods of rest or lower intensity exercise.
      • Morris N.R.
      • Walsh J.
      • Adams L.
      • et al.
      Exercise training in COPD: What is it about intensity?.
      Studies in people with COPD compared short duration (exercise period<180 s), high intensity (80-150% Wpeak) interval exercise with traditional continuous exercise training.
      • Morris N.R.
      • Walsh J.
      • Adams L.
      • et al.
      Exercise training in COPD: What is it about intensity?.
      • Zainuldin R.
      • Mackey M.G.
      • Alison J.A.
      Optimal intensity and type of leg exercise training for people with chronic obstructive pulmonary disease.
      However, despite training at higher intensities, when interval and continuous exercise were matched for total amount of work completed, there were no greater improvements in exercise capacity, HRQoL or any greater physiological adaptations with HIIT in COPD.
      • Morris N.R.
      • Walsh J.
      • Adams L.
      • et al.
      Exercise training in COPD: What is it about intensity?.
      • Zainuldin R.
      • Mackey M.G.
      • Alison J.A.
      Optimal intensity and type of leg exercise training for people with chronic obstructive pulmonary disease.
      It should be noted however, that when interval exercise is prescribed at the same absolute intensity as continuous exercise (i.e. not HIIT) then individuals with COPD are able to achieve greater amounts of work, demonstrate less dynamic hyperinflation, desaturate less and are less breathless.
      • Sabapathy S.
      • Kingsley R.A.
      • Schneider D.A.
      • et al.
      Continuous and intermittent exercise responses in individuals with chronic obstructive pulmonary disease.
      Interval exercise, prescribed at the same intensity as continuous exercise, has been used for individuals unable to tolerate continuous bouts of exercise training.
      • Spruit M.A.
      • Singh S.J.
      • Garvey C.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: key concepts and advances in pulmonary rehabilitation.
      • McCarthy B.
      • Casey D.
      • Devane D.
      • et al.
      Pulmonary rehabilitation for chronic obstructive pulmonary disease.
      • Rochester C.L.
      • Vogiatzis I.
      • Holland A.E.
      • et al.
      An Official American Thoracic Society/European Respiratory Society Policy Statement: Enhancing Implementation, Use, and Delivery of Pulmonary Rehabilitation.

      5.2 Inspiratory muscle training

      Several of the studies used inspiratory muscle training (IMT) as an adjunct to whole-body therapeutic exercise programs. In people with COPD, IMT applied at loads that exceed 30% of the maximum inspiratory pressure (MIP) improved the pressure-generating capacity of the inspiratory muscles.
      • Hill K.
      • Jenkins S.C.
      • Hillman D.R.
      • et al.
      Dyspnoea in COPD: can inspiratory muscle training help?.
      However, the clinical efficacy of IMT in terms of exercise capacity, dyspnoea and HRQoL, over and above the benefits achieved with therapeutic exercise alone, remains contradictory.
      • Beaumont M.
      • Mialon P.
      • Le Ber C.
      • et al.
      Effects of inspiratory muscle training on dyspnoea in severe COPD patients during pulmonary rehabilitation: controlled randomised trial.
      • Schultz K.
      • Jelusic D.
      • Wittmann M.
      • et al.
      Inspiratory muscle training does not improve clinical outcomes in 3-week COPD rehabilitation: results from a randomised controlled trial.
      Whilst an earlier meta-analysis suggested that IMT may convey some clinical benefit,
      • Gosselink R.
      • De Vos J.
      • van den Heuvel S.P.
      • et al.
      Impact of inspiratory muscle training in patients with COPD: what is the evidence?.
      two large RCTs published in 2018 reported negligible benefit of adding IMT to a program of therapeutic exercise in terms of improvements in exercise capacity and HRQoL, even in those with more severe disease.
      • Beaumont M.
      • Mialon P.
      • Le Ber C.
      • et al.
      Effects of inspiratory muscle training on dyspnoea in severe COPD patients during pulmonary rehabilitation: controlled randomised trial.
      • Schultz K.
      • Jelusic D.
      • Wittmann M.
      • et al.
      Inspiratory muscle training does not improve clinical outcomes in 3-week COPD rehabilitation: results from a randomised controlled trial.

      5.3 Exercise in water, active mind-body movement therapies and neuromuscular electrical stimulation

      Several systematic reviews have been published examining alternative approaches or adjuncts to therapeutic exercise in this population. Cochrane reviews have examined the role of water-based exercise,
      • McNamara R.J.
      • McKeough Z.J.
      • McKenzie D.K.
      • et al.
      Water-based exercise training for chronic obstructive pulmonary disease.
      active mind-body movement therapies (e.g. yoga, tai chi)
      • Gendron L.M.
      • Nyberg A.
      • Saey D.
      • et al.
      Active mind-body movement therapies as an adjunct to or in comparison with pulmonary rehabilitation for people with chronic obstructive pulmonary disease.
      • Ngai S.P.
      • Jones A.Y.
      • Tam W.W.
      Tai Chi for chronic obstructive pulmonary disease (COPD).
      and neuromuscular electrical stimulation (NMES)
      • Hill K.
      • Cavalheri V.
      • Mathur S.
      • et al.
      Neuromuscular electrostimulation for adults with chronic obstructive pulmonary disease.
      in COPD.
      Exercising in water has been proposed as an alternative to land-based exercise and provides buoyancy to support body weight, resistance to movement and a warm environment.
      • McNamara R.J.
      • McKeough Z.J.
      • McKenzie D.K.
      • et al.
      Water-based exercise training for chronic obstructive pulmonary disease.
      Water-based exercise is likely to be especially relevant for those who experience discomfort with walking and/or cycling due to comorbid conditions (e.g. osteoarthritis).
      • McNamara R.J.
      • McKeough Z.J.
      • McKenzie D.K.
      • et al.
      Water-based exercise training for chronic obstructive pulmonary disease.
      In people with COPD, when compared to no exercise, water-based exercise programs have been shown to improve both exercise capacity and HRQoL.
      • McNamara R.J.
      • McKeough Z.J.
      • McKenzie D.K.
      • et al.
      Water-based exercise training for chronic obstructive pulmonary disease.
      The magnitude of this change is similar to that seen with land-based exercise training.
      Studies using active mind-body movement therapies such as Tai Chi have shown improvements in HRQoL when compared to an unsupervised exercise program.
      • Ngai S.P.
      • Jones A.Y.
      • Tam W.W.
      Tai Chi for chronic obstructive pulmonary disease (COPD).
      One study in people with COPD reported that, compared to no exercise, a 12-week program of Tai Chi conducted twice weekly, increased both HRQoL and endurance shuttle walk distance.
      • Leung R.W.
      • McKeough Z.J.
      • Peters M.J.
      • et al.
      Short-form Sun-style t’ai chi as an exercise training modality in people with COPD.
      The exercise intensity of Tai Chi corresponded to approximately 50% of VO2reserve (VO2peak- VO2rest).
      • Leung R.W.
      • McKeough Z.J.
      • Peters M.J.
      • et al.
      Short-form Sun-style t’ai chi as an exercise training modality in people with COPD.
      However, adding Tai Chi to a traditional exercise program does not appear to provide any additional benefit.
      • Gendron L.M.
      • Nyberg A.
      • Saey D.
      • et al.
      Active mind-body movement therapies as an adjunct to or in comparison with pulmonary rehabilitation for people with chronic obstructive pulmonary disease.
      Adding NMES of the peripheral muscles has also been trialled as a strategy to improve exercise capacity. This intervention involves placing conductive pads over the muscle (usually the quadriceps) that are then attached to a stimulation unit. Increasing the stimulation activates the intramuscular nerve branches and muscle fibres resulting in muscle contraction. In COPD, when compared to no exercise, the application of NMES to the quadriceps muscle improves peripheral muscle strength and endurance, as well as exercise capacity.
      • Hill K.
      • Cavalheri V.
      • Mathur S.
      • et al.
      Neuromuscular electrostimulation for adults with chronic obstructive pulmonary disease.
      Nevertheless, there is little evidence to suggest that combining NMES with a traditional exercise program provides additional benefit over and above what is achieved with traditional exercise alone.
      • Hill K.
      • Cavalheri V.
      • Mathur S.
      • et al.
      Neuromuscular electrostimulation for adults with chronic obstructive pulmonary disease.
      The primary benefit for NMES would appear to be for severely debilitated individuals, unable to participate in more-traditional whole-body exercise programs.
      • Hill K.
      • Cavalheri V.
      • Mathur S.
      • et al.
      Neuromuscular electrostimulation for adults with chronic obstructive pulmonary disease.
      Whilst there is a growing body of evidence for alternative approaches to exercise training in COPD, it is also worth noting that: (i) reviews of alternative approaches to therapeutic exercise only include between 5 and 12 studies
      • McNamara R.J.
      • McKeough Z.J.
      • McKenzie D.K.
      • et al.
      Water-based exercise training for chronic obstructive pulmonary disease.
      • Hill K.
      • Cavalheri V.
      • Mathur S.
      • et al.
      Neuromuscular electrostimulation for adults with chronic obstructive pulmonary disease.
      (i.e. much less than the 65 included in the review of more traditional exercise training
      • McCarthy B.
      • Casey D.
      • Devane D.
      • et al.
      Pulmonary rehabilitation for chronic obstructive pulmonary disease.
      ), (ii) many of the conclusions are based on low-quality evidence, and (iii) the estimate of the effects were accompanied by wide 95% confidence intervals, which offer little precision for the prescribing therapist.

      5.4 Outcome measures

      Common assessments used to evaluate the effect of exercise training on exercise capacity include the 6MWT, incremental shuttle walk test (ISWT) and the cardiopulmonary exercise test (CPET).
      • Holland A.E.
      • Spruit M.A.
      • Troosters T.
      • et al.
      An official European Respiratory Society/American Thoracic Society technical standard: field walking tests in chronic respiratory disease.
      Regarding the assessment of other constructs, such as HRQoL, the St George’s Respiratory Questionnaire (SGRQ) and the Chronic Respiratory Disease Questionnaire (CRDQ) are the most commonly used disease-specific measure(Supplementary Table). Further, the COPD Assessment Test (CAT) is also a popular tool to assess health status in this population. The assessment of peripheral muscle strength, though likely to be important, is less commonly measured. In clinical practice, hand-held dynamometry is often used to quantify upper limb muscle strength, including grip strength. However, the distribution of muscle weakness in people with COPD is not uniform, and the strength of upper limb musculature, may not accurately reflect lower limb muscle strength.
      • Maltais F.
      • Decramer M.
      • Casaburi R.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: update on limb muscle dysfunction in chronic obstructive pulmonary disease.
      Assessment of lower limb muscle strength, such as the quadriceps, can be challenging. Hand-held dynamometry has been used in non-laboratory-based settings however the technique requires some assessment skill. Accurate assessment of quadriceps often requires more sophisticated equipment such as a commercial dynamometer (eg Biodex®).

      6. Limitations of evidence

      Whilst the reviews examining the role of traditional and alternative/adjunct approaches to therapeutic exercise training in people with COPD
      • McCarthy B.
      • Casey D.
      • Devane D.
      • et al.
      Pulmonary rehabilitation for chronic obstructive pulmonary disease.
      • McNamara R.J.
      • McKeough Z.J.
      • McKenzie D.K.
      • et al.
      Water-based exercise training for chronic obstructive pulmonary disease.
      • Gendron L.M.
      • Nyberg A.
      • Saey D.
      • et al.
      Active mind-body movement therapies as an adjunct to or in comparison with pulmonary rehabilitation for people with chronic obstructive pulmonary disease.
      • Ngai S.P.
      • Jones A.Y.
      • Tam W.W.
      Tai Chi for chronic obstructive pulmonary disease (COPD).
      • McKeough Z.J.
      • Velloso M.
      • Lima V.P.
      • et al.
      Upper limb exercise training for COPD.
      suggest a benefit for exercise capacity and HRQoL, the quality of evidence included in these reviews was typically downgraded. This was due, at least in part, to the high risk of performance bias and inconsistency in results (i.e. statistical heterogeneity).
      • Lacasse Y.
      • Cates C.J.
      • McCarthy B.
      • et al.
      This Cochrane Review is closed: deciding what constitutes enough research and where next for pulmonary rehabilitation in COPD.
      Further trials of therapeutic exercise versus usual care cannot change these limitations and the most recent Cochrane review of therapeutic exercise is now closed.
      • Lacasse Y.
      • Cates C.J.
      • McCarthy B.
      • et al.
      This Cochrane Review is closed: deciding what constitutes enough research and where next for pulmonary rehabilitation in COPD.
      Rather than examining the effect of exercise training (compared with no exercise training) on outcomes such as exercise capacity, HRQoL and symptoms, future work should focus on addressing issues such as; (i) the effect of therapeutic exercise on survival, (ii) strategies to maintain the benefits achieved following an exercise program and, (iii) optimising the translation of benefits achieved following an exercise program into increased participation in physical activity during daily life.
      • Lacasse Y.
      • Cates C.J.
      • McCarthy B.
      • et al.
      This Cochrane Review is closed: deciding what constitutes enough research and where next for pulmonary rehabilitation in COPD.
      A further possible limitation to the evidence is that many of the RCTs of therapeutic exercise in COPD exclude people with co-morbid conditions likely to limit exercise capacity, such as severe osteoarthritis, cardiac disease and peripheral vascular disease.
      • McCarthy B.
      • Casey D.
      • Devane D.
      • et al.
      Pulmonary rehabilitation for chronic obstructive pulmonary disease.
      However, it is well recognised that people with COPD present with multiple co-morbid conditions with previous studies suggesting that 29% of people with COPD referred to a rehabilitation program had five or more co-morbid conditions.
      • Noteboom B.
      • Jenkins S.
      • Maiorana A.
      • et al.
      Comorbidities and medication burden in patients with chronic obstructive pulmonary disease attending pulmonary rehabilitation.
      Therefore, the estimate of the effect of therapeutic exercise provided to date, may be overly ambitious for the people who are typically referred to a clinical therapeutic exercise program.
      Another consideration when examining the evidence for therapeutic exercise is that the estimate of the effect relates to between-group differences. Even though, in a group of people with COPD, an exercise intervention is likely to produce large, clinically meaningful improvements in exercise capacity, HRQoL, dyspnoea and fatigue there is clear evidence that the response varies considerably between individuals.
      • Spruit M.A.
      • Augustin I.M.
      • Vanfleteren L.E.
      • et al.
      Differential response to pulmonary rehabilitation in COPD: multidimensional profiling.
      In fact, nearly half of all people with COPD who complete an exercise-based rehabilitation program have a moderate or minimal response.
      • Spruit M.A.
      • Augustin I.M.
      • Vanfleteren L.E.
      • et al.
      Differential response to pulmonary rehabilitation in COPD: multidimensional profiling.
      Further work is needed to identify strategies and approaches that allow non-responders to become responders to exercise training.

      7. Special considerations

      One of the more contentious issues for clinicians involved in the delivery of an exercise-based rehabilitation program for COPD is how to manage transient exertional desaturation. It is generally accepted that those who have met the criteria for long-term oxygen therapy (LTOT) should use supplemental oxygen when exercising.
      • Spruit M.A.
      • Singh S.J.
      • Garvey C.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: key concepts and advances in pulmonary rehabilitation.
      However, the challenge is managing those who have acceptable arterial oxygen saturation at rest and do not meet the requirements to be prescribed LTOT, but demonstrate severe transient exertional desaturation. Whilst most would argue that severe transient exertional desaturation is something to be avoided, there is no clear evidence that severe transient exertional desaturation is dangerous
      • Afzal S.
      • Burge A.T.
      • Lee A.L.
      • et al.
      Should the 6-Minute Walk Test Be Stopped If Oxyhemoglobin Saturation Falls Below 80%?.
      or that using supplemental oxygen during exercise training to minimise this desaturation is beneficial.
      • Garrod R.
      • Paul E.A.
      • Wedzicha J.A.
      Supplemental oxygen during pulmonary rehabilitation in patients with COPD with exercise hypoxaemia.
      • Rooyackers J.M.
      • Dekhuijzen P.N.
      • Van Herwaarden C.L.
      • et al.
      Training with supplemental oxygen in patients with COPD and hypoxaemia at peak exercise.
      • Wadell K.
      • Henriksson-Larsen K.
      • Lundgren R.
      Physical training with and without oxygen in patients with chronic obstructive pulmonary disease and exercise-induced hypoxaemia.
      Indeed, a recently completed study, the largest RCT to date, examined exercise training combined with either oxygen supplementation or sham (air) in individuals with COPD who desaturated below 90% during a 6MWT, found no benefit in training on oxygen in terms of changes in exercise capacity or HRQoL.
      • Alison J.A.
      • McKeough Z.J.
      • Leung R.
      • et al.
      Oxygen compared to air during exercise training in COPD with exercise-induced desaturation.
      There is wide disparity in the management of this issue and the level of desaturation tolerated by clinicians delivering a pulmonary rehabilitation program appears arbitrary.
      • Johnston C.L.
      • Maxwell L.J.
      • Alison J.A.
      Pulmonary rehabilitation in Australia: a national survey.

      7.1 Uptake, adherence and completion

      Despite the strong evidence for the benefits of exercise training offered as part of a pulmonary rehabilitation program, accessing these programs is a major challenge. Astonishingly, studies conducted in seven countries over 18 years (1995–2013) show the proportion of people living with COPD who access these programs is <2%.
      • Holland A.E.
      Pulmonary rehabilitation for chronic obstructive pulmonary disease: Has it peaked?.
      Of those referred, one third did not attend their initial assessment and just less than half of those who commenced completed the program.
      • Holland A.E.
      Pulmonary rehabilitation for chronic obstructive pulmonary disease: Has it peaked?.
      A recent review extracted data from 48 studies to provide an overview of factors which influenced referral, uptake, attendance and/or completion of pulmonary rehabilitation programs.
      • Cox N.S.
      • Oliveira C.C.
      • Lahham A.
      • et al.
      Pulmonary rehabilitation referral and participation are commonly influenced by environment, knowledge, and beliefs about consequences: a systematic review using the Theoretical Domains Framework.
      Based on the results of this study, some strategies that may optimise participation in pulmonary rehabilitation are; (i) improved knowledge of referral processes, (ii) positive influence of referring doctor, (iii) improved understanding of perceived benefits and safety of exercise for this population and (iv) overcoming issues related to transport and parking costs associated with attending hospital-based programs.

      8. Recommendations

      Most therapeutic exercise programs for COPD are based on recommendations developed by the American College of Sports Medicine (ACSM),
      • American College of Sports Medicine
      ACSM’s Guidelines for Exercise Testing and Prescription.
      The American Thoracic Society(ATS)/European Respiratory Society (ERS)
      • Spruit M.A.
      • Singh S.J.
      • Garvey C.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: key concepts and advances in pulmonary rehabilitation.
      and/or the American Association of Cardiovascular and Pulmonary Rehabilitation (AACVPR).
      • Rehabilitation, A.A.o.C.a.P
      American Association of Cardiovascular and Pulmonary Rehabilitation Guidelines for Pulmonary Rehabilitation Programs Vol..
      Evidence based guidelines have also been published by the Lung Foundation/Thoracic Society of Australia and New Zealand (TSANZ),
      • Alison J.A.
      • McKeough Z.J.
      • Johnston K.
      • et al.
      Australian and New Zealand Pulmonary Rehabilitation Guidelines.
      the British Thoracic Society (BTS)
      • Bolton C.E.
      • Bevan-Smith E.F.
      • Blakey J.D.
      • et al.
      British Thoracic Society guideline on pulmonary rehabilitation in adults.
      and the Canadian Thoracic Society (CTS).
      • Marciniuk D.D.
      • Brooks D.
      • Butcher S.
      • et al.
      Optimizing pulmonary rehabilitation in chronic obstructive pulmonary disease–practical issues: a Canadian Thoracic Society Clinical Practice Guideline.
      For a comparison of these guidelines readers are directed toward a recently published, comparative review of major guidelines by the AACVPR.
      • Garvey C.
      • Bayles M.P.
      • Hamm L.F.
      • et al.
      Pulmonary Rehabilitation Exercise Prescription in Chronic Obstructive Pulmonary Disease: Review of Selected Guidelines: An Official Statement From The American Association Of Cardiovascular And Pulmonary Rehabilitation.
      From the practical perspective of establishing and delivering a therapeutic exercise program, readers are directed to the Lung Foundation of Australia and the Pulmonary Rehabilitation Toolkit.
      • Lung Foundation
      A. Pulmonary Rehabilitation Toolkit.
      This peer-reviewed, updated site provides an evidence-based approach for the management of COPD, including the prescription of therapeutic exercise.
      The recommendations (below) developed for Exercise and Sports Science Australia have been based primarily from the information obtained from the summary of RCTs (Supplementary Table). In developing these recommendations, the authors have also consulted guidelines from the ACSM, ATS, ERS AACVPR, TSANZ, BTS and CTS,
      • Spruit M.A.
      • Singh S.J.
      • Garvey C.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: key concepts and advances in pulmonary rehabilitation.
      • American College of Sports Medicine
      ACSM’s Guidelines for Exercise Testing and Prescription.
      • Rehabilitation, A.A.o.C.a.P
      American Association of Cardiovascular and Pulmonary Rehabilitation Guidelines for Pulmonary Rehabilitation Programs Vol..
      • Garvey C.
      • Bayles M.P.
      • Hamm L.F.
      • et al.
      Pulmonary Rehabilitation Exercise Prescription in Chronic Obstructive Pulmonary Disease: Review of Selected Guidelines: An Official Statement From The American Association Of Cardiovascular And Pulmonary Rehabilitation.
      ,
      • Alison J.A.
      • McKeough Z.J.
      • Johnston K.
      • et al.
      Australian and New Zealand Pulmonary Rehabilitation Guidelines.
      • Bolton C.E.
      • Bevan-Smith E.F.
      • Blakey J.D.
      • et al.
      British Thoracic Society guideline on pulmonary rehabilitation in adults.
      • Marciniuk D.D.
      • Brooks D.
      • Butcher S.
      • et al.
      Optimizing pulmonary rehabilitation in chronic obstructive pulmonary disease–practical issues: a Canadian Thoracic Society Clinical Practice Guideline.
      as well as the Pulmonary Rehabilitation Toolkit.
      • Lung Foundation
      A. Pulmonary Rehabilitation Toolkit.
      A summary of exercise recommendations is included in Table 2.
      Table 2Exercise prescription recommendations for chronic obstructive pulmonary disease.
      Type of exerciseIntensityFrequencyTimeSpecial considerations
      Aerobic

      ● Lower limb: Walking (treadmill or OG), cycling (ergometry)

      ● Upper Body: ergometry, shelving tasks
      ● RPE: 3-4 (modified BORG) or 12-14, BORG

      ● Dyspnoea: 3-4 (modified BORG)

      ● 40-60% Wpeak cycle ergometer

      ● 80% of 6MWT speed on treadmill
      ● 3-5 days per week

      ● 1-2 bouts per day
      ● 30-60 min per session

      ● Shorter sessions if > 1 bout per day

      ● Shorter interval exercise if unable to complete continuous exercise. Circuit training approach using 4-6 minute circuits for different upper and body exercise.
      ● Monitor status, consider modifying exercise if exacerbation

      ● Adjust intensity for angina/ischaemia, hemodynamic instability

      ● Monitor dyspnoea and SpO2 regularly. Note upper limb may elicit greater dyspnoea

      ● Depending on symptoms, during exercise testing cease exercise for SpO2≤80% and recommence exercise SpO2>85%

      ● During exercise training, cease exercise for SpO2<85% and recommence exercise SpO2>90%

      ● Consider medication interactions (β-blockers) associated with co-morbid conditions
      Resistance

      ● Machine/free weights

      ● Body weight
      ● 30-40% of 1 RM (upper body); 50-60% 1RM (lower body)

      ● or 8-15 comfortable reps
      ● 2-3 days per week● 10-20 min/d

      ● 8-10 exercises (major muscle groups), 10-15 reps
      ● Goals to ↑ SkM strength & endurance

      ● Avoid valsalva manoeuvre

      ● Circuit training if safe

      ● Changes in upper and lower body strength can be measured using hand-held dynamometer. Handgrip strength also be measured
      Flexibility exercises● 3-5 days per week30-60 s each muscle● Completed at the beginning/end of the session
      Aqua Therapy● RPE: 3-4 (modified BORG) or 12-14, BORG

      ● Dyspnoea: 3-4 (modified BORG)
      ● 1-2 per week● 30-60 min per session● Head up activity and ensure no CI for undertaking exercise in the water
      NMES● Maximum tolerable● 4 to 7 days per week

      ● 1-2 sessions per day
      ● 30 to 60 min per session● Only prescribed for individuals with severe disease and unable to undertake weight-bearing exercise due to severe breathlessness. Most commonly applied to quadriceps. Stimulation frequency commonly set at between 35 and 50 Hz. Protocols that target improvements in endurance may be characterised by low-frequency, high duty-cycle. Protocol that target improvements in strength may be characterised by e. high-frequency, low duty-cycle.
      CI: contraindications; OG: Overground; RM: repetition maximum; 6MWT: six minute walk test; SkM: skeletal muscle; SpO2: oxygen saturation.
      Wpeak: peak work rate.
      Given the likelihood of co-morbid conditions such as cardiovascular disease and the older age of the participants, it is recommended each participant undergoes a medical review prior to commencing an exercise program. Medical therapy should be optimised and participants should have received advice or commenced on appropriate risk management programs such as smoking cessation or removal from exposure to other environmental hazards contributing to COPD.
      • Yang I.A.
      • Brown J.L.
      • George J.
      • et al.
      COPD-X Australian and New Zealand guidelines for the diagnosis and management of chronic obstructive pulmonary disease: 2017 update.
      Aerobic exercise should be prescribed for upper and lower limbs. Lower limb exercise, such as walking or cycling, is recommended. Walking exercise can be undertaken as free (ground-based) walking or on a treadmill if attending a gym or using at home. Walking speeds can be calculated using the average speed achieved during the 6MWT. A walking speed equivalent to 80% of the average 6MWT speed is recommended at the start of an exercise program.
      • Lung Foundation
      A. Pulmonary Rehabilitation Toolkit.
      Training work rate on a cycle ergometer can be set at either a percentage of the Wpeak measured during a CPET or estimated from equations derived from the 6MWD.
      • Holland A.E.
      • Hill K.
      • Alison J.A.
      • et al.
      Estimating peak work rate during incremental cycle ergometry from the 6-minute walk distance: differences between reference equations.
      Intensity of exercise can also be set based on the severity of dyspnoea or rating of perceived exertion (RPE) using either the modified Borg scale (3-4) or the original Borg scale (12-14), respectively. After the initial prescription, intensity is usually titrated according to symptoms by increasing walking speed and grade (if using a treadmill) and/or the power on the cycle ergometer. Heart rate appears to be rarely used guide exercise intensity in people with moderate to severe lung disease.
      • McCarthy B.
      • Casey D.
      • Devane D.
      • et al.
      Pulmonary rehabilitation for chronic obstructive pulmonary disease.
      • Lung Foundation
      A. Pulmonary Rehabilitation Toolkit.
      High intensity interval training can be also be prescribed provided the participant is able to sustain short duration exercise at or near a peak power. We would recommend that the duration of exercise is kept short, one minute or less, to minimise an excessive ventilatory response which may limit further exercise.
      The inclusion of stretching and flexibility exercises in a rehabilitation program for COPD has been recommended by the ACSM, ATS and the AACVPR,
      • Spruit M.A.
      • Singh S.J.
      • Garvey C.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: key concepts and advances in pulmonary rehabilitation.
      • American College of Sports Medicine
      ACSM’s Guidelines for Exercise Testing and Prescription.
      • Rehabilitation, A.A.o.C.a.P
      American Association of Cardiovascular and Pulmonary Rehabilitation Guidelines for Pulmonary Rehabilitation Programs Vol..
      despite there being no clinical trials in this area. Slow movements that involve sustained stretch for up to 60 s for the major muscle groups of the upper and lower limb that can be conducted either at the beginning and/or the end of the rehabilitation program. Given that individuals with COPD are older, balance exercises could also be included with the flexibility program.
      • Chuatrakoon B.
      • Ngai S.P.C.
      • Sungkarat S.
      • et al.
      Balance Impairment and Effectiveness of Exercise Intervention in Chronic Obstructive Pulmonary Disease-A Systematic Review.
      Water-based exercise may also be prescribed, particularly for those with underlying musculoskeletal conditions which may limit exercise activity due to pain. For individuals with severe disease and more debilitated NMES may be useful. Where possible, these modalities should be considered as a ‘bridge’ to allow the person to participate in whole-body exercise training.
      With regards to monitoring, it is recommended that both symptoms (i.e. dyspnoea) and oxygen saturation are monitored during exercise training. Dyspnoea can be monitored using the modified Borg scale adapted for breathlessness.
      • Borg G.A.
      Psychophysical bases of perceived exertion.
      Based on current evidence, the absolute level of desaturation at which an individual should stop exercising remains arbitrary. The Australian Lung Foundation notes that individuals who desaturate below 88% even when participating in interval training should be assessed to determine the benefit of supplemental oxygen.
      • Lung Foundation
      A. Pulmonary Rehabilitation Toolkit.
      On the other hand, the technical standard for field walking tests in chronic respiratory disease endorsed by the ATS/ERS suggest ceasing an exercise test when SpO2 is ≤ 80%.
      • Holland A.E.
      • Spruit M.A.
      • Troosters T.
      • et al.
      An official European Respiratory Society/American Thoracic Society technical standard: field walking tests in chronic respiratory disease.
      Yet, a recent review of 549 individuals with chronic lung disease found that oxygen desaturation below 80% during the 6MWT was not associated with an increased risk of adverse event.
      • Afzal S.
      • Burge A.T.
      • Lee A.L.
      • et al.
      Should the 6-Minute Walk Test Be Stopped If Oxyhemoglobin Saturation Falls Below 80%?.
      We would recommend that both symptoms and SpO2 are constantly monitored throughout testing and training. We recommend different criteria for the cessation of exercise, for exercise testing vs exercise training. Ceasing exercise testing when SpO2 is ≤ 80% would be safe and conservative approach.
      • Holland A.E.
      • Spruit M.A.
      • Troosters T.
      • et al.
      An official European Respiratory Society/American Thoracic Society technical standard: field walking tests in chronic respiratory disease.
      Exercise testing may be recommenced when SpO2 is >85%.
      • Holland A.E.
      • Spruit M.A.
      • Troosters T.
      • et al.
      An official European Respiratory Society/American Thoracic Society technical standard: field walking tests in chronic respiratory disease.
      However, during aerobic training, we would recommend that clinicians apply higher thresholds for the minimal acceptable level of SpO2, such as <85% or <88% and recommence exercise when SpO2 is >90%. During both testing and training, in addition to monitoring SpO2, clinicians also need to closely monitor symptoms which may be associated with a cardiac limitation, such as excessive shortness of breath, dizziness and chest tightness or pain, and be guided by these when deciding to impose a rest and/or cease exercise. The decision to halt exercise testing or training should be made based on the evaluation of all signs and symptoms, not just the degree of desaturation.
      • Holland A.E.
      • Spruit M.A.
      • Troosters T.
      • et al.
      An official European Respiratory Society/American Thoracic Society technical standard: field walking tests in chronic respiratory disease.
      The optimal exercise training frequency and duration is three to five times per week (often achieved as a combination of supervised and unsupervised sessions) ideally for 40 to 60 min per session. Shorter duration (20-40 min) programs could be used at commencement. Individuals with COPD initially unable to complete a continuous exercise bout due to the onset of intolerable symptoms should complete shorter bouts of interval exercise as tolerated to achieve a total exercise time of 20 to 40 min per session. As exercise tolerance increases, interval exercise can be progressed, by increasing the exercise period duration and decreasing the duration and/or frequency of the rest periods. Total exercise time can also be extended to 40-60 minutes as tolerance increases. Upper limb exercise can be prescribed using arm ergometry or undertaking ‘shelving’ (i.e. lifting small weights from waist to over the shoulder height) tasks. The special considerations are outlined in Table 2.
      Respiratory medications should be optimised prior to commencing an exercise program.
      • Yang I.A.
      • Brown J.L.
      • George J.
      • et al.
      COPD-X Australian and New Zealand guidelines for the diagnosis and management of chronic obstructive pulmonary disease: 2017 update.
      Regular bronchodilator therapy should be continued when undertaking exercise program; most participants do not require additional short-acting bronchodilators prior to exercise. Table 3 outlines the common COPD medications and the potential side effects which may affect exercise performance.
      Table 3Summary of medications (and exercise-specific side-effects) commonly prescribed for people of chronic obstructive pulmonary disease.
      MedicationActionGroupsGeneric examplesExercise-specific side effects
      • Australian Medicines Handbook 2019(online)
      Adelaide: Australian Medicines Handbook Pty Ltd; 2019 January.
      β2-agonists● stimulate β2-receptors on airway smooth muscle and mast cells resulting in bronchodilatation and inhibition of mast cell mediator release● Short acting β2 agonists (SABA –“Relievers”)● Salbutamol

      ● Terbutaline
      ● Increased heart rate/palpitations

      ● Tremor

      ● Cardiac arrythmias (rare)

      ● metabolic acidosis (rare, respiratory compensation due to increased lactate levels)

      ● Peripheral vasodilation (rare)
      ● Long acting β2 agonists (LABA)● Formoterol

      ● Salmeterol

      ● Indacaterol
      Anti-muscarinic Drugs● Block the muscarinic effects of acetylcholine on nicotinic receptors resulting in airway. smooth muscle relaxation● Short-acting muscarinic antagonists – (SAMA)● Ipratropium● Cardiac arrythmias (rare)

      ● Dry mouth, throat irritation, cough

      ● Headache (common>1%)

      ● ECG changes (rare)

      ● Dizziness
      ● Long-Acting muscarinic antagonists – (LAMA)● Tiotropium

      ● Aclidinium

      ● Glycopyrronium

      ● Umeclidinium
      Corticosteroids● Suppress airway inflammation through genomic and non-genomic pathways● Inhaled corticosteroids (ICS, “Preventers”)● Fluticasone (as furoate or propionate)

      ● Budesonide

      ● Beclometasone

      ● Ciclesonide
      ● Osteoporosis screening recommended for adults on long term high dose ICS
      Combination● Corticosteroids/β2 agonist● ICS/LABA combinations● Budesonide/formoterol

      ● Fluticasone furoate /Vilanterol

      ● Fluticasone Propionate /Salmeterol

      ● Futicasone Propionate /Formoterol (*PBS asthma only)
      ● See individual agent side effect profile
      ● Muscarinic/β2 agonist● LAMA/LABA combinations● Tiotropium/Olodaterol

      ● Aclidinium/Formoterol

      ● Glycopyrronium/Indacaterol

      ● Umeclidinium/Vilanterol
      ● See individual agent side effect profile
      ● Corticosteroids/Muscarinic/β2 agonist● ICS/LAMA/LABA● Fluticasone Furoate/Umeclidinium/ Vilanterol● See individual agent side effect profile
      Note: All side effects described are dose-dependent.
      Resistance exercise is also recommended to improve peripheral muscle strength and endurance for upper and lower limbs. Where available, weight machines and free weights should be employed to ensure an accurate prescription. The intensity can be fixed as a percentage of a repetition maximum (RM); however, the RPE could also be used to set the training intensity. More ‘functional’ exercise such as step-ups and sit to stands can also be prescribed to improve strength, these being particularly useful for home-based exercise programs. Duration and frequency details are outlined in Table 2.
      We would endorse the inclusion of home-based program consisting of both aerobic and resistance exercises for the upper and lower limbs. Depending on the frequency of the supervised exercise program, the home-based program could be undertaken at least two to three days per week and consist of at least 30 minutes of walking exercise and functional strengthening exercises for the upper and lower limb. On completion of a supervised program, participants should be encouraged to continue with a maintenance exercise program for three to five days per week. Walking at least 30 minutes in duration is recommended, at a similar intensity prescribed during the supervised exercise program. It is also recommended that participants continue with a once weekly supervised exercise class or have their unsupervised maintenance program reviewed every three to six months.
      • Lung Foundation
      A. Pulmonary Rehabilitation Toolkit.

      9. Contraindications

      Both the ATS/ERS note that there are a few contraindications to therapeutic exercise in COPD.
      • Spruit M.A.
      • Singh S.J.
      • Garvey C.
      • et al.
      An official American Thoracic Society/European Respiratory Society statement: key concepts and advances in pulmonary rehabilitation.
      As with any exercise program, however, absolute and relative contraindications for exercise, as outlined by the ACSM, should be observed.
      • American College of Sports Medicine
      ACSM’s Guidelines for Exercise Testing and Prescription.
      These include neurological, orthopaedic and cardiac disorders which may put the patient at unacceptable risk with performing exercise.

      10. Summary

      For individuals with COPD, exercise-based rehabilitation is a highly effective, safe, non-invasive therapeutic treatment option for improving exercise capacity and HRQoL. Exercise has been prescribed for individuals with severe disease in both an outpatient and inpatient setting. Challenges for this intervention remain; limited availability of supervised rehabilitation programs, poor referral and uptake patterns constrain the potential positive effects. Improved access and greater uptake of supervised exercise programs will improve outcomes and make a profound difference to the HRQoL for individuals with COPD.

      Acknowledgement

      The authors would like to thank Ms Menaka Louis for undertaking the additional review of literature and preparation of the supplementary data table.

      Appendix A. Supplementary data

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