Introduction: Chronic Respiratory Diseases (CRDs) are increasing worldwide; more than half of the sufferers live in low- and middle-income countries (LMICs). People with CRDs live with troublesome symptoms, especially breathlessness and fatigue, which reduce their exercise capacity and ability to maintain activity levels. This affects quality-of-life, and overall performance, with many people developing co-morbid anxiety and depression. Pulmonary Rehabilitation (PR) aims to reverse the vicious circle of breathlessness, avoidance of activity, muscle weakness, and further increasing inactivity. There is strong evidence (mainly from high-income countries) that PR improves functional exercise capacity and quality of life, and guidelines recommend PR as an integral part of CRDs care. Despite the potential that implementation of PR could reduce the burden of CRDs, it is notably underprovided in LMICs. AIMS AND OBJECTIVES: I aimed to adapt and test the feasibility of a PR programme to be delivered in a low resource setting and initiate strategies for the implementation of this complex intervention in Bangladesh. My objectives were: • Engage relevant stakeholders, explore, and integrate their views. • Conduct a systematic review to synthesise the clinical effectiveness, components, and mode of delivery of PR in low-resource settings. • Identify core components from global PR guidelines. • Adapt PR protocol for implementation in Bangladesh. • Undertake a feasibility study using mixed-method (quantitative and qualitative) research. • With stakeholders, develop and initiate an ongoing implementation strategy for scaling up and delivering PR in Bangladesh. METHODS: The PhD work proceeded in six phases addressing these objectives: Stakeholder engagement: I selected stakeholders according to their interest and influence; conducting seven meetings across the country to engage them in this implementation research programme and to learn about the context. Systematic Review: I reviewed literature systematically following the Cochrane methodology to identify the evidence generated from LMICs on the effectiveness (improvement of functional exercise capacity and health-related quality of life), useable components, and deliverable models of PR services in a low -resource setting. I searched six databases from 1990 to 2018 with a pre-publication forward citation search in 2020. Global Guidelines Recommendations: I reviewed international PR guidelines and identified the key recommended components of PR. I also visited internationally-recognised centres to learn practical techniques. Adapting a PR programme to the Bangladesh context: I mapped each of the recommended components of PR to an approach that could be delivered in a low resource setting and tailored to the Bangladesh context. Feasibility Study: I planned a mixed-methods, before-and-after feasibility study of PR delivered to groups in my community-based clinic in Khulna. The feasibility study was interrupted by the COVID-19 pandemic. The original intention was to conduct an 8-week centre-based PR programme with face-to-face supervised sessions, including exercise and educational programmes. After completing about one-third of the study, this was suspended due to the pandemic. After a delay of three months, I resumed the feasibility study, having adapted the PR programme for home delivery (with Centre-based assessments) in line with national social distancing regulations and the Sponsor's requirements. Quantitative Analysis: I compared pre- and post-measurements of exercise capacity (ESWT: Endurance Shuttle Walking Test) and quality-of-life (CAT: COPD Assessment Test) using T-tests or non-parametric tests according to the distribution of the data. Secondary outcomes included dyspnoea and anxiety/depression. Qualitative data collection and analysis: Interviews with 15 patients, eleven professionals, two hospital/clinic owners cum managers, and three other stakeholders were recorded, transcribed verbatim, and analysed using two approaches: A grounded theory approach explored patients' views on living with CRDs and the acceptability, benefits, challenges, and enablers for PR. A framework approach, using the Normalisation Process Theory (NPT) Toolkit to understand professional/stakeholder' views about implementing PR in clinical practice. Finally, I synthesised the findings from both the quantitative and qualitative methods to answer the objectives of the feasibility study. Develop implementation strategy: I am working with stakeholders to raise awareness meetings, workshops, seminars, and symposiums on PR as a continuous process for the implementation and integration of PR services in routine clinical practice in Bangladesh. Results: Initial stakeholder meetings identified multiple challenges: lack of research evidence on clinical effectiveness in Bangladesh, poor patient health literacy, economic and cultural barriers, widespread exposure to risk factors, and lack of knowledge among health professionals. There is a need to educate professionals (and specifically train PR therapists), involve influential political and religious leaders, and provide accessible services. These broadly align with the policy statement of ATS/ERS with regard to raising awareness and generating evidence on PR in our own context. The systematic review included 13 controlled studies evaluating the effectiveness of PR in LMICs. In most studies, functional exercise capacity and quality of life improved, but 11/13 studies were at high risk of bias. One of the two studies at moderate risk of bias showed no benefit. All programmes included exercise training; most provided education, chest physiotherapy, and breathing exercises. Adapted to the setting, low-cost services used limited equipment and typically combined outpatient/centre delivery with a home/community-based service. From global PR guidelines, I developed a matrix of the practical components with a detailed description of each element and models of delivery in various settings. The components recommended in global PR guidelines are typically described for delivery in high-income settings. I, therefore, adapted the components to my local low-resource community-based context to develop a protocol for PR in Bangladesh. The feasibility study commenced as a Centre-based programme before the pandemic. Of 296 patients referred from my practice, 89 (30%) patients participated allocated to one of four unisex groups. Of the 207 (70%) who refused centre-based PR, 107 (52%) preferred home-based, 69 (33%) community-based, and only 32 (15%) declined to participate in the research, citing concern that PR might exacerbate their breathlessness, or impose an extra financial burden. The first group had completed 70% of the sessions, the second group had completed 50% of the sessions; the third and fourth groups had just started their programmes when the study was suddenly suspended due to the COVID-19 pandemic. Adapted for home delivery in the pandemic. Sixty-one patients were referred for PR; 51 participated (mean age 55 years (SD 12); M: F 33:18). Forty-four patients (86%) completed 11 (70%) of the remotely supervised sessions. Forty participants (78%) attended the post-PR assessment at eight weeks. Quantitative Analysis: Functional exercise capacity measured by Endurance Shuttle Walking Test (ESWT) improved by 345 seconds (Minimum Clinically Important Difference (MCID) is 174s). Pre: median (IQR) 291 (119, 989) vs post: 544 (60, 1200); P < 0.0001. Quality-of-life measured by the COPD Assessment Test improved by 7 (MCID is 2), Pre: median (IQR) 16.5 (4, 28) vs post: 7.5 (0, 26); p<0.0001. Patients defined their condition by the symptoms (as opposed to a disease). Some were surprised at being offered an exercise programme that triggered breathlessness (the symptom they were trying to cure). Most patients were concerned about the affordability and availability of the service. Professionals perceived PR as a novel intervention, and were aware of evidence of its effectiveness, but had no personal experience on which to base their opinions. Implementation strategy. Building on the evidence from this PhD, I am working on continuous stakeholder engagement, building awareness, and developing skilled professionals through seminars, symposiums and workshops. Conclusions: PR is an integral part of care of the increasing burden of CRDs. It is effective, deliverable, and has applicable components for our context. The feasibility study demonstrated the acceptability and potential benefits of implementing PR in Bangladesh. Stakeholder engagement, especially with influential groups, is the key to implementation. Improving awareness, developing a skilled workforce, and a cost-effective, affordable and easily accessible PR model are pre-requisites of providing patients with CRDs.