Pulmonary rehabilitation in lung transplantation: Its effects on pulmonary function, physical fitness, and quality of life

Abstract

Lung transplantation (LTx) is the definitive therapy for patients with end-stage lung disease and improves survival. However, many recipients continue to experience exercise intolerance, reduced physical capacity, and limitations in daily activities despite improved postoperative lung function. These impairments are multifactorial and closely associated with quality of life (QoL) and long-term outcomes. Pulmonary rehabilitation (PR) is a multidisciplinary intervention aimed at improving exercise capacity, physical fitness, and QoL and has demonstrated benefits across various chronic lung diseases. This narrative review synthesizes current evidence on PR in LTx recipients. A literature review was conducted to summarize PR program characteristics, safety, and reported outcomes across lung function, functional capacity, muscle fitness, activity and participation, and QoL, considering heterogeneity in study design and intervention protocols. Across the reviewed studies, PR participation was consistently associated with improvements in cardiorespiratory fitness, muscle strength, functional capacity, and QoL. In contrast, changes in spirometric parameters were generally modest. Functional improvements appear to be largely mediated by peripheral adaptations, including enhanced oxygen utilization and neuromuscular performance. These findings highlight the potential role of PR as an important component of short- and long-term management in LTx recipients, particularly during pre-transplant conditioning and post-transplant functional recovery phases.

Key Words: Cardiorespiratory fitness; Exercise tolerance; Lung diseases; Lung transplantation; Muscle strength

Core Tip: Lung transplantation (LTx) improves survival in end-stage lung disease, yet many recipients experience persistent exercise intolerance despite adequate graft function. This review highlights pulmonary rehabilitation (PR) as a safe and effective intervention throughout LTx care. PR programs, typically combining aerobic and resistance training with education, are associated with minimal adverse events. Evidence demonstrates improvements in cardiorespiratory fitness, muscular fitness, and quality of life, while changes in lung function are modest. These benefits are driven by peripheral physiological adaptations, including enhanced muscle oxidative capacity and neuromuscular efficiency. PR represents a fundamental strategy to optimize functional recovery in LTx recipients.

INTRODUCTION

Lung transplantation (LTx) is the definitive therapeutic option for selected patients with end-stage lung disease who are refractory to conventional medical therapy and has been shown to prolong survival in severe pulmonary conditions, including idiopathic pulmonary fibrosis and chronic obstructive pulmonary disease (COPD)[1,2]. In addition to improvements in surgical techniques and immune management, post-LTx survival rates have significantly improved over the past few decades, with a median survival of approximately 5.8-6.2 years[2,3].

However, many transplant recipients still experience significant exercise intolerance, limitations in physical capacity, and activities of daily living even though their lung function returns to near normal after surgery[4,5]. This decrease in exercise capacity is multifactorial, including peripheral muscle dysfunction, deconditioning, changes in pulmonary mechanics and gas exchange, and the effects of ongoing immunosuppression. This limitation is clinically important because exercise capacity is an important predictor of quality of life (QoL) and several other long-term outcomes in LTx recipients[4-8].

Pulmonary rehabilitation (PR) is a multidisciplinary intervention that includes aerobic exercise, resistance training, respiratory muscle training, education, and behavior modification to improve physical exercise capacity and QoL[9,10]. In other chronic lung disease populations, PR has been shown to improve exercise capacity or cardiorespiratory fitness (CRF), reduce dyspnea symptoms, and improve survival and QoL[11-13] Studies in LTx candidates and recipients have also shown that PR has a positive effect on exercise capacity, including 6-minute walk distance, peak oxygen uptake (VO₂ peak), and peripheral muscle strength[14-16].

Despite evidence supporting the beneficial effects of PR on physical functioning, the existing literature remains heterogeneous in terms of study designs, exercise protocols, intervention durations, and measured outcomes, making it challenging to derive an integrated understanding of the full spectrum of PR effects in LTx recipients[17-21]. Most studies primarily report outcomes such as exercise capacity or QoL[21-25]. However, a comprehensive synthesis that simultaneously addresses the effects of PR on pulmonary function, CRF, muscular fitness, activity and participation, and overall QoL within a unified narrative is still lacking.

In addition, adverse events related to PR programs in LTx recipients and the physiological mechanisms underlying functional improvement after PR are also rarely described in detail in a single comprehensive review[15]. However, understanding the safety profile and functional improvement mechanisms is important to guide clinical practice and the design of more effective PR programs.

The objective of this narrative review was to integrate the existing evidence and to provide a more comprehensive overview of the role of PR in LTx recipients. This review described the current evidence on PR in LTx recipients, including intervention characteristics and reported adverse events, as well as its effects on pulmonary function, CRF, muscular fitness, activity and participation, and QoL. In addition, this review explored the proposed mechanisms underlying physiological improvements following PR and the factors that may influence these physiological responses. By offering an integrated synthesis of the available literature, this review aimed to support clinical reasoning and to identify knowledge gaps that may guide future research in the field of rehabilitation for LTx recipients.

LITERATURE REVIEW

This article was conducted using a narrative review approach to integrate the available scientific evidence on the role of PR in LTx recipients. A literature search was conducted across several electronic databases, including PubMed, Web of Science, Scopus, and ResearchGate, as well as through the Google Scholar search engine. In addition, hand searching of reference lists from relevant articles was undertaken to identify additional publications. Keywords used were “pulmonary rehabilitation” OR “exercise” OR “training” OR “breathing exercise” OR “breathing retraining” OR “physiotherapy” OR “physical therapy” AND ‘lung transplantation” OR “lung transplant” OR “pulmonary transplantation” OR “pulmonary transplant” AND “dyspnea” OR “breathlessness” OR “shortness of breath” OR “symptoms” OR “lung function” OR “pulmonary function” OR “functional capacity” OR “aerobic capacity” OR “6MWT” OR “VO₂peak” OR “cardiorespiratory fitness” OR “psychological function” OR “cognitive function” OR “activity of daily living” OR “daily activity” OR “participation” OR “job” OR “work” OR “quality of life” OR “HRQoL”. No restrictions were applied regarding the year of publication. Only peer-reviewed articles published in English were considered eligible, while grey literature was not included. The literature search and synthesis were performed by two independent reviewers (Nazir A and Rachmaniar S).

The inclusion criteria comprised all types of original research articles reporting PR or exercise-based PR interventions in adult patients undergoing or having undergone LTx, either in the pre-operative or post-operative phase. Interventions conducted in hospital-based or home-based settings were eligible for inclusion. Studies that did not report at least one outcome relevant to the objectives of this review were excluded. Study selection was performed through an initial screening of titles and abstracts, followed by a full-text review of articles that met the preliminary inclusion criteria.

Data from the selected studies were extracted and synthesized narratively and summarized in tabular form. Extracted information included author, year of publication, study design, study objectives, population and sample characteristics, characteristics of the PR intervention, measured outcomes, and key findings. The outcomes analyzed in this review included symptoms, pulmonary function, functional capacity (such as six-minute walk test distance and VO₂ peak), respiratory and peripheral muscle strength, psychological and cognitive function, activity and participation, and QoL.

A narrative review approach was chosen because the primary aim of this review was to provide a broad conceptual synthesis of the role of PR in LTx recipients. This review sought not only to summarize the effects of interventions on specific outcomes but also to integrate multiple aspects of the available evidence, including intervention characteristics, reported clinical outcomes, potential adverse events, and proposed physiological mechanisms underlying improvements following PR. Therefore, a narrative approach was considered more appropriate to allow a comprehensive integration and interpretation of the literature. Consequently, formal methodological quality assessment and meta-analysis were not performed in this review.

SUMMARY OF FINDINGS

PR in LTx recipients

PR is defined as a comprehensive intervention that begins with a multidimensional patient assessment, followed by individually tailored therapy, including exercise, education, and behavioral modification, to improve physical and psychological well-being and promote long-term adherence to healthy behaviors. This approach emphasizes personalized intervention without prescribing a specific structure or setting, making it relevant for center-based, community-based, and distance-based models. The comprehensive assessment includes nutritional status, psychological well-being, and functional capacity, which serve as the basis for program adjustments and appropriate referral pathways[9].

Essential components of PR include evaluation of exercise capacity, dyspnea level, health-related QoL, and personalized endurance and resistance training supervised by an experienced healthcare professional. Desirable additional components include individualized education, self-management training, physical activity counseling, upper limb exercises, and airway clearance techniques. Although evidence for the effects of each of these additional components is limited, their presence supports the delivery of evidence-based care and provides an optimal environment to improve clinical outcomes in patients with chronic lung disease[9].

PR represents an important intervention for patients with advanced lung disease, both before and after LTx. In the pre-transplant setting, PR, often referred to as prehabilitation, aims to optimize physical capacity, mitigate deconditioning, and prepare patients for major surgical procedures associated with substantial perioperative risk. However, the optimal duration and specific protocols of pre-transplant PR have not been well established, largely due to the uncertainty surrounding transplant waiting times. In addition to its physiological benefits, PR facilitates patient education regarding surgical procedures, medication effects, and recovery strategies, thereby supporting more informed and shared decision-making[10,26].

Patients with advanced lung disease often experience severe dyspnea, activity limitations, and skeletal muscle dysfunction, which are major factors in exercise intolerance. Pre- and post-transplant PR has been shown to increase muscle strength, VO₂ peak, and endurance, as well as reduce muscle fatigue, thus improving exercise capacity, surgical tolerance, and long-term outcomes[10,26].

Following LTx, despite substantial improvements in pulmonary function, patients may continue to experience functional disability due to persistent weakness of the expiratory muscles and lower extremities, which can last for up to 1-3 years. Post-transplant PR typically comprises multimodal interventions, including aerobic and resistance training, early mobilization, flexibility exercises, disease- and therapy-related education, and self-management strategies. PR programs are commonly delivered over a duration of 6-8 weeks, with a frequency of two to three sessions per week, and exercise intensity is individually tailored according to patient tolerance[10].

Functional assessment of LTx candidates and recipients encompasses aerobic capacity [e.g., the 6-minute walk test (6MWT) and VO₂ peak], peripheral muscle strength and mass (particularly the quadriceps and lower extremities), mobility, and activities of daily living. This multidimensional assessment facilitates individualized exercise prescription, oxygen titration, and the prevention of rehabilitation-related complications. Long-term maintenance through sustained exercise training (> 6 months), regular physical activity, and ongoing clinical monitoring is essential to preserve improvements in functional capacity, muscle strength, and QoL[27] (Table 1).

Table 1 Pulmonary rehabilitation in lung transplantation recipients based on rehabilitation phases.

Rehabilitation phase	Objective	Intervention/program
Pre-transplant (pre-LTx)	(1) Maintain or improve functional capacity and muscle strength before surgery; and (2) Reduce the risk of post-operative complications, accelerate recovery, and improve QoL	(1) Aerobic training and upper- and lower-limb strength training performed 2-3 times per week for 6-8 weeks; exercise intensity progressively increased according to individual tolerance; inspiratory breathing exercises; interval, resistance, or single-leg training modalities; (2) Initial assessment: Hemodynamic stability, oxygen requirements, bone mineral status, BMI, comorbidities, respiratory mechanics, functional capacity (6MWT, CPET), muscle strength, and QoL; and (3) Education and supportive care: Familiarization with surgical procedures; secretion management, controlled coughing techniques, incentive spirometry, wound care and pain management, and early mobilization; disease-specific education (oxygen therapy, pharmacological treatment, activities of daily living, pacing, and energy conservation); psychological support, nutritional counseling, and occupational therapy
Post-LTx hospitalization	(1) Reduce weakness associated with ICU-acquired weakness; and (2) Improve lower-extremity muscle strength, balance, and gait performance to minimize the risk of falls	(1) Initiated within 24 hours postoperatively: Early mobilization, breathing exercises, airway clearance, and postural optimization; (2) Respiratory reconditioning, evaluation of supplemental oxygen requirements, strengthening of upper-extremity and lower-extremity ROM, and management of neuropathic pain; (3) Supervised ambulation and bed-to-chair transfer training, with careful management of chest tubes and pain; (4) Gradual lower-extremity resistance training, with attention to upper-limb ROM and loading restrictions during the first approximately 6 weeks; and (5) Provision of medical and adaptive equipment at hospital discharge
Early post-LTx phase (0-12 months)	(1) Improve exercise capacity, muscle strength, QoL, participation in daily activities; and (2) Prevent complications associated with immunosuppression, diabetes, osteoporosis, and tendinopathy	(1) Early initiation of outpatient PR following hospital discharge; (2) Baseline assessment of functional capacity and muscle strength; (3) Progressive exercise training with gradual increases in intensity and duration; (4) Hygiene education to prevent infection and reduce the risk of graft rejection; (5) Interval training, warm-up, and stretching exercises to prevent tendon injury; and (6) Monitoring of comorbidities and postoperative medication adjustments
Long-term post-LTx phase (> 12 months)	(1) Maintain or further improve exercise capacity and muscle function; and (2) Address long-term effects of chronic rejection, reduce dyspnea, and enhance QoL	(1) Combined aerobic and resistance training of the upper and lower extremities, performed 3-5 times per week; (2) Gradual progression of exercise duration (30-120 minutes per week) at an intensity of 50-80% of peak work rate; (3) Remote monitoring or telehealth-based supervision; (4) Emphasis on structural muscle adaptations, including mitochondrial function, strength, type I and II muscle fiber composition, and fiber cross-sectional area; and (5) Supervised outpatient programs for patients experiencing functional decline or chronic rejection

LTx: Lung transplantation; QoL: Quality of life; ICU: Intensive care unit; BMI: Body mass index; 6MWT: Six-minute walk test; CPET: Cardiopulmonary exercise testing; ROM: Range of motion; PR: Pulmonary rehabilitation.

Although PR is recommended in both phases of care, the current body of evidence summarized in this review is predominantly derived from studies evaluating rehabilitation during the post-transplant recovery period, whereas studies specifically investigating structured pre-transplant rehabilitation remain relatively limited.

Overall, the available literature consistently indicates that PR plays an important role in supporting functional recovery in LTx recipients. Across studies summarized in Table 2, PR programs were associated with improvements in exercise capacity, peripheral muscle strength, daily activity performance, and health-related QoL, although the magnitude and consistency of these effects varied across study designs, intervention characteristics, and outcome measures.

Table 2 Summary of studies on effects of pulmonary rehabilitation on functioning in lung transplantation recipients.

No.	Ref.	Study design	Study objective	Study population	Pulmonary rehabilitation intervention	Outcomes assessed	Main results
1	Ambrosino et al[29], 1996	Prospective longitudinal	To evaluate the trajectory of exercise capacity and skeletal and respiratory muscle function after heart-lung transplantation	11 HLT patients (age 38 ± 13 years)	Maximal treadmill exercise, resistive inspiratory training, limb strength training	Pulmonary function; 6MWD; VO2 peak; MIP/MEP; lower-limb muscle strength	No significant change in pulmonary function; gradual improvements in VO2 peak, 6MWD, and muscle strength, but values remained below normal
2	Andrianopoulos et al[17], 2019	Pre-post study	To assess the short-term effects of post-LTx PR on pulmonary function, exercise capacity, and cognitive function	24 LTx recipients with COPD	Comprehensive inpatient PR for 3 weeks	DLCO; RV/TLC; 6MWD; cognitive function	DLCO increased, hyperinflation decreased, 6MWD improved significantly (+ 86 m), and cognitive function improved
3	Candemir et al[22], 2019	Pre-post study	To evaluate the effectiveness of outpatient PR after bilateral LTx	23 bilateral LTx recipients	Multidisciplinary outpatient PR for 8 weeks	Exercise capacity; muscle strength; pulmonary function; QoL; psychological status	Significant improvements in exercise capacity, muscle strength, QoL, and psychological status; static pulmonary function did not change
4	Kerti et al[21], 2021	Pre-post study	To evaluate the effectiveness of PR before and after transplantation	63 LTx candidates and 14 LTx recipients	Four-week PR: Personalized breathing and aerobic exercise	Pulmonary function; 6MWD; CWE; dyspnea; QoL	Pre-LTx PR improved CWE, CAT score, and 6MWD; post-LTx PR improved pulmonary function and quality of life
5	Munro et al[18], 2009	Prospective repeated-measures	To describe functional changes during post-LTx PR	36 LTx recipients	Outpatient PR for 12 weeks (3 times per week)	6MWD; FEV1; FVC; QoL (SF-36)	Significant improvements in pulmonary function, 6MWD, and all SF-36 domains
6	Langer et al[23], 2012	Randomized controlled trial	To evaluate the effect of early supervised exercise after LTx on functional recovery	40 LTx patients (intervention n = 21; control n = 19)	Supervised exercise for 3 months	Daily activity; physical fitness; QoL	The exercise group showed greater daily walking time, higher 6MWD, and greater muscle strength
7	Maury et al[20], 2008	Cohort study	To assess the impact of post-LTx rehabilitation on muscle function and exercise tolerance	36 LTx patients	Outpatient PR for 3 months	Quadriceps strength; 6MWD; pulmonary function	Significant improvements in 6MWD and muscle strength, but values did not reach normal levels
8	Ulvestad et al[31], 2020	Randomized controlled trial	To evaluate the effects of HIIT on fitness and muscle strength after LTx	54 LTx recipients	Supervised HIIT for 20 weeks	VO2 peak; muscle strength; QoL; pulmonary function	No significant difference in VO2 peak (ITT); improvements in muscle strength and mental components of QoL
9	Bartels et al[33], 2011	Observational study	To compare pulmonary function and exercise capacity before and after LTx	153 LTx recipients	Post-LTx PR and physical exercise	Pulmonary function; CPET	Pulmonary function improved significantly, but VO2 peak remained < 50% of predicted values
10	van Adrichem et al[34], 2015	Longitudinal cohort	To analyze changes in 6MWD and its predictors after LTx	108 LTx recipients	Recommendation for regular exercise after LTx	6MWD; pulmonary function; muscle strength	6MWD improved significantly; FEV1 and muscle strength predicted optimal functional recovery
11	Ulvestad et al[24], 2020	Cohort study	To assess respiratory fitness, physical activity, and factors contributing to exercise intolerance after LTx	54 LTx recipients	Postoperative PR up to 6 months	Cardiorespiratory fitness; physical activity	VO2 peak after BLTx remained low due to deconditioning, ventilatory limitation, and impaired gas exchange; most patients were physically inactive
12	Mei et al[25], 2024	Quasi-experimental	To evaluate the effectiveness of early comprehensive PR after LTx	LTx patients at Shanghai Pulmonary Hospital	Multidisciplinary comprehensive PR initiated 24 hours postoperatively	Pulmonary function; 6MWD; QoL; clinical outcomes	Shorter ICU LOS and better pulmonary function, 6MWD, and QoL compared with controls
13	Schneeberger et al[30], 2017	Retrospective cohort	To evaluate PR outcomes in SLTx and DLTx	722 LTx recipients	Multimodal inpatient PR (approximately 6 weeks)	6MWD; HRQoL	Significant improvements in 6MWD and HRQoL with no difference between SLTx and DLTx
14	Orens et al[36], 1995	Prospective	To evaluate exercise responses during the first year after single and double lung transplantation	14 SLTx and 11 DLTx recipients, stable ≥ 3 months post-LTx	Incremental cycle ergometer CPET every 3 months for 1 year	CPET variables; spirometry; DLCO; MVV	Lung function differed between groups, but exercise responses were similar; VO2 peak increased at 3-6 months then declined at 9-12 months
15	Dierich et al[32], 2013	Prospective observational cohort	To observe the influence of postoperative clinical course on inpatient PR success	Single, double, and combined LTx recipients (≥ 18 years)	Three-week inpatient PR: Interval training, strength training, respiratory physiotherapy, education, psychological support	PWR; VO2 peak; 6MWD; VC; FEV1; ADL; HRQoL	All physical function parameters and HRQoL improved significantly; differences observed in PWR, 6MWD, and SF-36 physical functioning
16	Byrd et al[19], 2024	Retrospective non-inferiority	To compare group-based vs individual PR	110 LTx recipients	Outpatient group-based vs individual PR	6MWD; physical function; QoL	Individual PR was non-inferior to group-based PR
17	Song et al[39], 2018	Retrospective cohort	To evaluate feasibility and outcomes of early PR initiated in the ICU after LTx	22 LTx recipients	Early ICU PR: Chest physiotherapy, limb ROM, position changes, functional progression (G1-G4)	Physical functional level	PR initiated at a median of 7.5 days post-LTx without complications; 64% achieved ambulation before discharge
18	Wu et al[35], 2022	Randomized controlled trial	To evaluate the effects of early extubation combined with physical exercise after LTx	96 LTx patients (intervention n = 48; control n = 48)	Early extubation plus early physical exercise 3-5 times per week for 4 weeks	Pulmonary function; 6MWD; MBI; LOS; satisfaction	Intervention group showed better pulmonary function, 6MWD, and MBI (P < 0.001), shorter intubation duration and LOS, and higher satisfaction
19	Fuller et al[38], 2017	Randomized controlled trial	To compare short-duration (7 weeks) vs long-duration (14 weeks) PR after LTx	66 LTx recipients	Supervised PR 3 times per week: Aerobic and resistance training	6MWD; quadriceps/hamstring strength; QoL	Both groups improved in 6MWD and muscle strength with no significant difference between program durations

LTx: Lung transplantation; PR: Pulmonary rehabilitation; HIIT: High-intensity interval training; 6MWD: Six-minute walk distance; SLTx: Single lung transplantation; DLTx: Double lung transplantation; ICU: Intensive care unit; HLT: Heterotopic liver transplantation; COPD: Chronic obstructive pulmonary disease; CPET: Cardiopulmonary exercise testing; ROM: Range of motion; VO₂ peak: Peak oxygen uptake; MIP: Maximal inspiratory pressure; MEP: Maximal expiratory pressure; ; DLCO: Diffusing capacity of the lung for carbon monoxide; MVV: Maximal voluntary ventilation; RV: Residual volume; TLC: Total lung capacity; QoL: Quality of life; CWE: Constant work-rate exercise; FEV1: Forced expiratory volume in one second; FVC: Forced vital capacity; SF-36: Short Form 36; CPET: Cardiopulmonary exercise testing; HRQoL: Health-related quality of life; PWR: Peak work rate; VC: Vital capacity; ADL: Activities of daily living; MBI: Modified Barthel Index; LOS: Length of stay; CAT: Chronic obstructive pulmonary disease assessment test; ITT: Intention-to-treat; BLTx: Bilateral lung transplantation.

Taken together, PR in LTx recipients represents an important clinical strategy targeting exercise capacity, muscle function, mobility, and QoL through a multimodal, individualized, and evidence-based approach, both before and after transplantation[10,13,26]. Table 1 describes the goals of PR and interventions given based on rehabilitation phases in LTx recipients[28].

Adverse events during the pr program in LTx recipients

Adverse events during PR programs in LTx recipients were relatively uncommon and were generally not directly attributable to the rehabilitation intervention itself. One patient was reported to have died from cytomegalovirus pneumonia before functional evaluation could be performed; therefore, this death was not related to the PR program. In addition, one patient experienced bilateral phrenic nerve injury, which was a pre-existing condition at the time of hospital admission[29].

Post-transplant clinical complications, including surgical wound issues, opportunistic infections, and episodes of acute lung rejection, were reported despite participation in PR programs[29]. However, evidence from multiple studies indicated that no adverse events were directly related to PR. Several studies reported that PR programs were safe and feasible[17], with no cardiovascular events or other serious complications occurring during exercise sessions[21,22,24,25,30].

Exercise-related effects were limited to mild musculoskeletal discomfort during training sessions and were not classified as serious adverse events. Other medical events occurring during the study periods such as chronic lung allograft rejection, recurrent respiratory infections, progression of systemic sclerosis, and myocardial infarction, were reported but were not directly associated with PR participation[31].

Some patients encountered barriers to completing PR programs due to clinical complications, including neuropathy following prolonged mechanical ventilation, necessitating transfer to transplant centers for continuation of physiotherapy once clinically stable[32]. Additionally, some patients were excluded from analyses due to pre- or postoperative coronavirus disease 2019 infection, and others were unable to complete six-minute walk distance (6MWD) assessments for medical reasons; however, no adverse events attributable to PR were reported in these cases[19].

THE EFFECT OF PR ON PULMONARY FUNCTION, PHYSICAL FITNESS, AND QOL

Effects on pulmonary function

Several studies have demonstrated that PR in the post-LTx phase may improve lung function. However, the magnitude and consistency of these effects vary considerably across intervention parameters and study designs (Table 2). In lung transplant recipients with COPD, a three-week comprehensive inpatient PR program was associated with a significant increase in the diffusing capacity of the lung for carbon monoxide (DLCO) of + 4.3% and a reduction in static hyperinflation, reflected by a 2.3% decrease in the residual volume to total lung capacity ratio[17]. These findings suggest that PR may favorably influence lung mechanics and gas exchange efficiency during the post-transplant period.

Consistent observations were reported in another study, which demonstrated significant improvements in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) following a 12-week outpatient PR program conducted three times per week. This intervention combined structured exercise training with multidisciplinary education, and the overall exercise dose was comparable to the minimum recommended levels for individuals with chronic lung disease, supporting its capacity to induce measurable physiological adaptations[18].

Nevertheless, not all studies have reported significant improvements in lung function following PR[20,22,29]. One study observed that although ambulatory PR improved functional capacity after transplantation, changes in FEV1 were not the primary determinant of enhanced exercise tolerance, indicating a predominant contribution of peripheral adaptations. Similarly, another study reported no significant changes in FEV1, FVC, or dyspnea scores after outpatient PR, while a prospective longitudinal study found no significant changes in dynamic or static lung volumes up to 12 months following heart-LTx[22,29].

Studies employing higher exercise intensities have yielded comparable findings. In a randomized controlled trial, 20 weeks of high-intensity interval training (HIIT) did not result in significant between-group differences in lung function parameters, including FEV1, maximal voluntary ventilation, or DLCO, compared with usual care[31].

In contrast, a large observational study clearly demonstrated that LTx itself leads to marked improvements in pulmonary function relative to pre-transplant values, with increases in FVC (67%), maximal voluntary ventilation (91%), and FEV1 (136%). Despite these substantial gains, improvements in exercise capacity remained limited, underscoring a dissociation between recovery of lung function and restoration of maximal functional performance[33].

Lung function has also been identified as a predictor of post-transplant functional outcomes. One study reported that FEV1 (% predicted) significantly contributed to changes in 6MWD and predicted the attainment of optimal functional capacity at 12 months post-transplantation[34]. This observation is supported by another study in which FEV1 was among the clinical variables collectively explaining 73% of the variance in VO₂ peak in bilateral LTx recipients[24].

During the early recovery phase, very early initiation of PR appears to confer additional benefits. A comprehensive postoperative PR program commenced within 24 hours of transplantation was associated with significantly better lung function and oxygenation indices compared with standard care[25]. Comparable results were observed when early extubation was combined with early physical exercise, leading to greater improvements in FEV1%, FVC%, and the FEV1/FVC ratio relative to control groups[35].

Finally, procedural factors also influence post-transplant lung function trajectories. At three months post-transplantation, recipients of single LTx (SLTx) for chronic airflow obstruction or idiopathic pulmonary fibrosis exhibited lower FEV1 (% predicted) than double LTx (DLTx) recipients, although ventilatory responses during exercise were largely comparable[36]. Additionally, a three-week inpatient PR program was shown to significantly improve FEV1 and vital capacity across patients, with no significant differences between those with prolonged postoperative courses and those without complications[32].

Although several studies reported small improvements in spirometric parameters such as FEV1 and FVC, these findings were generally modest and inconsistent across studies. In contrast, improvements in functional outcomes, including exercise capacity and muscle strength, were more consistently observed following PR.

Effects on CRF

Multiple studies have consistently demonstrated that PR exerts beneficial effects on CRF and exercise tolerance in LTx recipients, although the magnitude and durability of these improvements vary across studies. In the early post-transplant phase, an intensive three-week inpatient PR program was reported to significantly enhance exercise capacity, as reflected by an increase of + 86 m in the 6MWD. This magnitude of improvement was comparable to that reported in studies employing longer PR durations, such as seven-week programs yielding a + 95 m increase in 6MWD. Despite the shorter intervention period, lower baseline 6MWD values and higher exercise intensity were proposed to contribute to the greater training response observed in this cohort[17]. This observation is consistent with evidence indicating that lower baseline exercise capacity is associated with greater rehabilitation-related gains[37].

Improvements in exercise tolerance among LTx recipients have also been linked to the ability to achieve higher heart rates during functional testing, thereby enabling greater walking distances during the 6MWT. These adaptations are thought to be mediated by improvements in respiratory and peripheral muscle function, which directly enhance walking efficiency and overall functional performance[17]. In the outpatient setting, a comprehensive multidisciplinary PR program in bilateral LTx recipients was shown to significantly improve incremental shuttle walk test performance from 23% to 36% after eight weeks of PR, accompanied by a meaningful increase in endurance shuttle walk test outcomes[22]. Similar findings were reported in another study, in which outpatient PR led to a significant increase in 6MWD from 451 ± 126 m to 543 ± 107 m[18].

Enhanced exercise capacity has also been observed in studies combining aerobic and resistance training, resulting in significant improvements in 6MWD and functional exercise tolerance following LTx. In one such study, 6MWD increased by 140 ± 91 m (P < 0.05), although sex-specific differences were noted, with smaller gains observed among female participants[20]. In contrast, pre-transplant PR was associated with a significant increase in 6MWD from 315 ± 118 m to 375 ± 114 m, whereas comparable improvements were not observed in the post-transplant phase. The authors attributed this discrepancy to reduced physical fitness related to prolonged intensive care unit (ICU) stays, resulting in inactivity and early post-transplant deconditioning[21].

Assessment of exercise capacity using maximal exercise testing and VO₂ peak measurements further indicates that CRF improves progressively following transplantation and rehabilitation; however, these improvements remain partial and gradual. One study reported that although VO₂ peak and treadmill performance increased at six and twelve months post-transplant, values did not reach normal ranges. The same longitudinal study demonstrated a progressive increase in 6MWD during follow-up, reflecting improvements in activities of daily living despite incomplete recovery of CRF[29]. These findings are supported by another study showing that supervised exercise training for three months after hospital discharge significantly improved 6MWD compared with controls, with sustained benefits observed up to one-year post-transplantatio[23].

At higher exercise intensities, one study reported that intention-to-treat analysis revealed no significant difference in VO₂ peak changes between HIIT and control groups. However, per-protocol analysis excluding participants with adherence below 70% demonstrated a significant increase in VO₂ peak in the HIIT group, underscoring the critical role of adherence in maximizing fitness-related adaptations[31]. Overall, peak exercise parameters assessed by cardiopulmonary exercise testing indicate that although exercise capacity may increase by approximately 1.5-2-fold following transplantation, VO₂ peak typically reaches only around 50% of predicted normal values. Notably, patients with the lowest pre-transplant exercise capacity tend to exhibit the greatest post-transplant improvements[33].

Despite substantial functional gains during the early post-transplant period, improvements in 6MWD do not consistently continue over the long term. One study reported that gains in 6MWD plateaued between six and twelve months post-transplantation, with 58.3% of LTx recipients failing to achieve ≥ 82% of predicted values at 12 months[34]. Persistent limitations in CRF were further highlighted by findings showing mean VO₂ peak values of only 57% ± 17% of predicted in men and 70% ± 12% in women, with merely 6% of patients reaching normal levels. Deconditioning was identified as the primary cause of exercise intolerance (41%), followed by ventilatory limitation (26%) and impaired gas exchange (37%). Furthermore, 86% of patients did not meet World Health Organization physical activity recommendations, and physical activity levels showed a moderate correlation with VO₂ peak (r = 0.642; P < 0.01), alongside body mass index, sex, and hemoglobin concentration as key determinants of post-transplant fitness[24].

Several studies have also indicated that the beneficial effects of PR on exercise capacity are relatively consistent across transplant procedures. Comparable improvements in 6MWD have been reported between SLTx and DLTx recipients, regardless of underlying diagnoses such as COPD or interstitial lung disease, with no significant procedural differences observed[30]. These findings are supported by another study demonstrating similar cardiopulmonary exercise testing-derived exercise responses, including VO₂ peak and peak work rate, between SLTx and DLTx recipients throughout the first post-transplant year[36]. Nevertheless, postoperative clinical course appears to influence rehabilitation outcomes, as patients experiencing prolonged postoperative recovery exhibited smaller improvements in peak work rate and 6MWD compared with those without complications[32].

Finally, the model and duration of PR programs also influence fitness-related outcomes. One study reported that both seven-week and fourteen-week PR programs produced significant improvements in 6MWD, with no significant differences observed at six months post-transplantation[38]. Similarly, outpatient PR delivered in either group-based or individualized formats resulted in comparable improvements in functional exercise capacity in both pre-transplant and post-transplant settings[19]. In interventional studies, PR groups consistently demonstrated greater improvements in 6MWD than control groups, and the combination of early extubation with early physical exercise was shown to significantly enhance CRF compared with standard care[25,35].

Effects on muscular fitness

PR, particularly in lung transplant recipients, has demonstrated consistent beneficial effects on peripheral and respiratory muscle fitness, although the magnitude and statistical significance of these improvements varied across studies. In outpatient PR programs initiated after LTx, significant increases in upper-limb and lower-limb muscle strength as well as respiratory muscle strength were observed, as reflected by improvements in maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP) compared with baseline values[22]. In contrast, early longitudinal studies reported non-significant improvements in MIP, MEP, and isometric strength of lower-limb flexor and extensor muscles, with skeletal and respiratory muscle strength remaining below normal reference ranges up to 6-12 months after transplantation[29]. Similar findings were reported in other studies that did not observe significant improvements in handgrip strength following PR in either the pre-LTx or post-LTx phases[21].

Resistance training combined with aerobic exercise appeared to exert a more pronounced effect on the recovery of peripheral muscle strength. Exercise interventions incorporating leg press training alongside aerobic exercise resulted in significantly greater improvements in quadriceps strength compared with control groups that received only physical activity advice during a one-year follow-up period[23]. These findings were consistent with other studies demonstrating increased quadriceps force after three months of structured resistance and aerobic training. Furthermore, post-transplant PR was reported to increase quadriceps muscle strength by 35% ± 48% (P < 0.05); however, muscle strength remained below pre-transplant levels, indicating the persistence of residual peripheral muscle deficits[20].

Improvements in muscle function were also reported to occur gradually over time following transplantation. Respiratory muscle performance (MIP and MEP) and lower-limb peripheral muscle strength, assessed using isokinetic extensor and flexor torque measurements, demonstrated upward trends, although early changes were not statistically significant, and values remained below normal ranges up to one year after LTx[29]. Structured exercise interventions were again confirmed to be effective in enhancing quadriceps muscle strength, supporting the role of resistance training in counteracting deconditioning associated with surgery and prolonged immobilization[23].

Higher-intensity exercise approaches yielded additional promising outcomes. The combination of HIIT and strength training resulted in significant improvements in peripheral muscle strength, evidenced by an intergroup difference of 11.6 kg in one-repetition maximum leg press, as well as a trend toward improvement in one-repetition maximum arm press, although handgrip strength did not differ significantly between groups[31]. Clinically, peripheral muscle strength - particularly quadriceps and handgrip strength - contributed substantially to variability in functional capacity. The combination of FEV1 at hospital discharge and quadriceps or handgrip strength emerged as a significant predictor of achieving ≥ 82% of the predicted 6MWT distance at 12 months after LTx[34].

However, the duration of rehabilitation programs did not consistently correlate with gains in muscle strength. A study comparing PR durations of 7 weeks and 14 weeks found no significant differences in quadriceps or hamstring strength, as measured by peak torque, at six months post-intervention, suggesting that factors beyond training duration play a critical role in peripheral muscle adaptation[38].

Effects on activity, participation, and QoL

PR has been shown to exert positive effects on activity, participation, QoL in patients both before and after LTx, although the magnitude and specific domains of improvement varied across studies. Outpatient PR programs initiated after LTx were reported to produce significant improvements in St George’s Respiratory Questionnaire and Chronic Respiratory Questionnaire scores, accompanied by reductions in Hospital Anxiety and Depression Scale scores, reflecting decreased symptoms of anxiety and depression[22]. Other studies assessing QoL using the Short Form 36 (SF-36) similarly demonstrated significant improvements across all quality-of-life domains following rehabilitation interventions[18].

Improvements in QoL after post-transplant PR appeared to be time dependent. Greater gains were observed during the first and second months compared with subsequent periods, which was hypothesized to reflect the cumulative effects of early interventions, including surgery, intensive medical care, pain management, and physical rehabilitation. Pain reduction during the early postoperative phase facilitated increased physical activity, which in turn contributed to improvements in physical and social functioning and overall QoL through the completion of the rehabilitation program[18].

From an activity and participation perspective, patients who participated in structured exercise programs demonstrated significant improvements in self-reported physical function and daily activity participation, as evidenced by longer daily walking durations compared with control groups[23]. Beyond physical outcomes, PR was also associated with improvements in cognitive function, with approximately half of the neurocognitive tests showing enhancement, particularly in learning and memory domains. These changes may support improved daily functioning and overall QoL among lung transplant recipients[17].

The clinical benefits of PR on QoL were observed in both pre- and post-transplant phases. Reductions in COPD Assessment Test scores indicated clinically meaningful improvements in QoL, despite the absence of significant changes in dyspnea severity as measured by the modified Medical Research Council scale, suggesting that PR primarily influenced health perception and functional status rather than short-term subjective respiratory symptoms[21]. In higher-intensity training approaches, patients undergoing HIIT demonstrated significant improvements in the mental component of QoL, as reflected by increases in the SF-36 Mental Component Summary (MCS), without significant differences in the physical component[31].

Consistently, health-related QoL assessed using the St George’s Respiratory Questionnaire was reported to be significantly better in PR groups compared with control groups[22]. Improvements were also observed in the Physical Component Summary and MCS of the SF-36, with reported increases of 6-9 points in Physical Component Summary and 7-10 points in MCS. These improvements did not differ significantly between recipients of SLTx and DLTx, nor between patients with COPD and those with interstitial lung disease[30].

Physical function and activities of daily living improved significantly after PR across all patient groups, despite longer postoperative clinical courses in some individuals. However, patients with prolonged or complicated postoperative courses exhibited smaller gains in the SF-36 physical functioning domain compared with those without complications, although all QoL domains still showed significant improvement following inpatient PR[32].

Assessment of physical performance using the Short Physical Performance Battery demonstrated improvements after PR, with no significant differences between group-based and individualized rehabilitation models or between pre-transplant and post-transplant phases. Similar findings were reported for physical QoL assessed using the Ferrans and Powers QoL Index Pulmonary Version, with significant post-rehabilitation improvements and no differences according to rehabilitation model or transplant phase. Additionally, no significant between-group differences were observed in depressive symptoms or dyspnea severity[19].

In the context of early rehabilitation, PR initiated during the ICU phase resulted in significant improvements in post-transplant physical function. Most patients transitioned from low functional levels to ambulatory status, with the majority maintaining ambulation until hospital discharge, and no rehabilitation-related complications were reported[39]. Other observational studies also demonstrated superior physical function outcomes, as measured by the Modified Barthel Index, along with earlier mobilization, shorter intubation duration, and reduced hospital length of stay, although no significant differences in ICU length of stay were observed. Patient satisfaction was higher in groups receiving early extubation and physical exercise, although standardized QoL outcomes were not specifically reported[35].

Conversely, longer rehabilitation duration did not consistently translate into greater QoL improvements. No significant differences were observed between 7-week and 14-week rehabilitation programs in either physical or mental QoL domains following intervention, suggesting that the timing and quality of rehabilitation interventions may be more influential than program duration alone in determining QoL outcomes[38].

Overall, PR was consistently associated with improvements in functional outcomes, particularly exercise capacity and peripheral muscle strength. In contrast, changes in spirometric parameters were generally modest and less consistent across studies.

PHYSIOLOGICAL MECHANISM OF FUNCTIONAL IMPROVEMENTS AFTER PR IN LTX RECIPIENTS

Post-LTx PR has been consistently shown to improve multiple aspects of physical function and QoL. PR programs initiated shortly after hospital discharge, or as early as 24-72 hours postoperatively, support the recovery of lung function through progressive breathing exercises transitioning from passive to active movements. These interventions enhance respiratory muscle strength and endurance, reduce fatigue, and improve ventilatory capacity[25,39]. Improvements in functional exercise capacity have also been demonstrated by increases in 6MWD, higher peak workloads during ergometer testing, and enhanced lower-limb muscle strength - particularly of the quadriceps - which represents a key determinant of exercise tolerance and functional capacity after transplantation[20,23,34].

High-intensity resistance training, including leg press or knee extensor resistance training, has proven effective in increasing lower-limb and peripheral muscle strength, thereby reducing the relative physiological burden of daily activities and promoting greater participation in physical activities of daily living[23,31]. These gains in muscle strength also contribute to improved oxygen utilization efficiency during exercise, support enhancements in CRF, and are associated with reductions in mean arterial blood pressure and cardiovascular morbidity during the first year following LTx[23,24].

Beyond physiological benefits, PR exerts positive psychosocial effects by enhancing self-efficacy and motivation for physical activity, reducing symptoms of depression and anxiety, and improving health-related QoL perceptions across both physical and mental domains[19,25,30]. Collectively, PR facilitates comprehensive recovery by modulating lung function, CRF, muscular fitness, daily activity performance, social participation, and overall QoL (Table 3)[35,38].

Table 3 Physiological mechanism of functional improvements after pulmonary rehabilitation in lung transplantation recipients.

Domain/output	Repair mechanism	Factors affecting the amount of improvement
Lung function	Progressive breathing exercises increase respiratory muscle strength and endurance, resulting in increased FEV1, FVC, faster extubation, optimal ventilation	ICU length of stay, transplant type, patient baseline condition, exercise intensity, and adherence
Cardiorespiratory fitness/exercise tolerance	Aerobic and HIIT training improves work capacity, oxygen efficiency, and participation in daily activities. It also leads to increased functional exercise tolerance	Compliance with exercise, achieved HIIT intensity, ventilatory capacity (FEV1, respiratory reserve), time to PR initiation (< 2 years post-LTx), sedentary behavior
Muscle fitness	High-intensity resistance training increases leg muscle strength, facilitating functional activity and exercise capacity. Training respiratory muscles reduces fatigue	Initial muscle weakness, duration of ICU stays, steroid/immunosuppressive use, type of exercise (resistance vs light), compliance
Activities and participation	Increased muscle strength and exercise capacity make daily activities easier to perform with relatively lower stress. Supervised exercise increases self-efficacy	Sedentary behavior, motivation level, outpatient rehabilitation support, exercise compliance
Quality of life	Increased physical capacity, participation, and social/psychological interaction during PR improves perceptions of physical and mental health	Duration and intensity of PR, duration of hospitalization, initial condition of the patient, ceiling effect on mental scores, compliance
Cardiovascular morbidity	Physical activity lowers blood pressure through acute reductions in vascular resistance and chronic adaptations of the autonomic nervous system. Exercise prevents hypertension and diabetes after LTx	Physical activity level, extreme sedentary behavior, post-transplant lifestyle

FEV1: Forced expiratory volume in one second; FVC: Forced vital capacity; HIIT: High-intensity interval training; PR: Pulmonary rehabilitation; LTx: Lung transplantation; ICU: Intensive care unit.

The magnitude of improvement achieved through PR is influenced by a range of patient- and intervention-related factors. Patient-related determinants include the degree of pre-transplant muscle weakness, duration of hospitalization and ICU stay, type of transplantation, and the presence of comorbid conditions such as COPD, interstitial lung disease, or chronic lung allograft dysfunction[20,24,33]. Recovery of peripheral muscle function - particularly quadriceps strength - emerges as a principal driver of functional capacity improvement, whereas handgrip strength appears to serve primarily as a marker of general physical condition rather than a direct determinant of exercise performance[34].

Intervention-related factors encompass adherence to the exercise program, achieved training intensity, type and duration of exercise, and timing of PR initiation after transplantation. HIIT and high-intensity resistance training programs have demonstrated significant improvements in VO₂ peak and muscle strength predominantly among participants with high adherence, while individuals with ventilatory limitations or low baseline activity levels exhibit more modest gains[31,38]. Additionally, physiological factors such as immunosuppressive therapy, glucocorticoid use, anemia, and elevated body mass index may attenuate CRF recovery despite substantial improvements in lung function[31,33].

Rehabilitation duration and delivery format (outpatient vs inpatient, group-based vs individualized) appear to exert less influence on key outcomes than training intensity, consistency, and patient motivation. Notably, extending program duration by an additional seven weeks does not necessarily yield incremental benefits, whereas regular follow-up contacts and structured interactions enhance adherence and help sustain functional improvements over time[19,38].

Overall, the benefits of post-LTx PR reflect a complex interplay between physiological responsiveness to exercise, intervention quality and adherence, and individual clinical characteristics. Optimal recovery requires a structured, multidimensional approach targeting peripheral muscle fitness and CRF, daily physical activity, and psychosocial support - particularly during the first 6-12 months following transplantation - to promote long-term functional capacity and QoL[24,34,39].

Despite the heterogeneity in PR protocols across studies, several patterns can be identified from the available evidence. Exercise-based PR, most commonly consisting of aerobic training combined with resistance or strength exercises, appears to be the most consistently beneficial component. Many studies implementing supervised exercise programs reported improvements in functional capacity measures such as 6MWT distance and muscle strength. For example, improvements in 6MWT distance were reported in multiple studies[17,20,29,30,38], while gains in peripheral muscle strength were observed in several studies[20,22,23,38]. These findings suggest that structured exercise training is a central component contributing to functional recovery after LTx. Importantly, the majority of these findings originate from studies conducted during the post-LTx PR phase, whereas evidence describing the effects of structured pre-LTx PR programs remains comparatively limited.

In contrast, evidence regarding improvements in pulmonary function is less consistent. Several studies reported no significant changes in spirometric parameters following PR[22,29], whereas others observed improvements in pulmonary function outcomes such as FEV1, DLCO, or hyperinflation indices[17,18,35]. These mixed findings suggest that improvements in functional capacity following PR may be primarily mediated by peripheral adaptations rather than substantial changes in lung function itself.

Similarly, evidence regarding CRF measured by VO₂ peak remains variable across studies. While some studies observed gradual increases in VO₂ peak after rehabilitation[29], others reported no significant changes despite structured training interventions[24,31]. In addition, although several studies reported improvements in QoL and psychological outcomes, these outcomes were not consistently assessed across all studies, limiting direct comparison[22,30,32].

LIMITATIONS OF THE CURRENT EVIDENCE

Although the available literature generally supports the beneficial role of PR in LTx recipients, several methodological limitations should be considered when interpreting these findings. As summarized in Table 2, the majority of the included studies employed observational, cohort, or pre-post designs without control groups, which limits the ability to establish causal relationships between PR and the observed functional improvements. Among the 19 studies included in this review, only a small proportion were randomized controlled trials, and most of these trials involved relatively modest sample sizes.

In addition, many studies were conducted in single centers and included relatively small cohorts of patients, often fewer than 40 participants. Although this reflects the limited availability of LTx recipients in clinical practice, small sample sizes reduce statistical power and limit the generalizability of findings. Substantial heterogeneity was also observed across studies in terms of rehabilitation protocols, exercise intensity, program duration, and timing of rehabilitation initiation, ranging from early ICU-based mobilization to outpatient rehabilitation programs conducted months after transplantation.

Outcome measures also varied considerably across studies, including pulmonary function parameters, 6MWT distance, VO₂ peak, muscle strength, daily physical activity, and various QoL instruments. This diversity complicates direct comparison across studies and limits the ability to identify the most effective rehabilitation protocols. Furthermore, adherence to exercise interventions and long-term follow-up outcomes were inconsistently reported. Several studies demonstrated improvements only in per-protocol analyses, suggesting that patient adherence may substantially influence rehabilitation outcomes.

Finally, most studies primarily focused on short- to medium-term outcomes, whereas long-term sustainability of rehabilitation-related benefits remains insufficiently characterized. These methodological limitations highlight the need for larger multicenter trials, standardized PR protocols, and longer follow-up periods to better define the long-term impact of PR in LTx recipients.

FUTURE RESEARCH DIRECTIONS

Future research should prioritize the development of standardized PR protocols specifically tailored for LTx recipients. Important areas of investigation include determining the optimal timing of rehabilitation initiation, identifying the most effective combinations of aerobic and resistance training modalities, and defining appropriate exercise intensity thresholds that maximize physiological adaptations while maintaining safety.

In addition, further randomized controlled trials with larger multicenter cohorts are required to strengthen the current evidence base and to clarify the long-term effects of PR on functional capacity, graft outcomes, and survival. The role of innovative rehabilitation delivery models, including tele-rehabilitation and hybrid home-based programs, also warrants investigation, particularly in the context of improving accessibility and long-term adherence to exercise programs among LTx recipients.

Future studies should also explore the mechanistic pathways underlying functional recovery after transplantation, including the interaction between peripheral muscle adaptations, cardiopulmonary responses to exercise, and the influence of immunosuppressive therapy. Improved understanding of these mechanisms may help guide individualized rehabilitation strategies and optimize long-term recovery trajectories in lung transplant recipients.

From an implementation perspective, PR programs in centers with limited resources may prioritize several core components consistently associated with functional benefits. These include aerobic exercise (e.g., walking or cycling), basic resistance exercises targeting major muscle groups, particularly the lower extremities, breathing exercises, and patient education to promote physical activity and self-management. Even when comprehensive multidisciplinary programs are not feasible, these essential elements may still provide meaningful improvements in functional capacity and physical performance in LTx recipients.

CONCLUSION

This narrative review integrated the current body of evidence and demonstrated that PR is a safe and effective intervention for LTx recipients when implemented in a structured and individualized manner across different phases of care. PR programs typically comprise progressive aerobic and resistance training, breathing exercises, patient education, and multidisciplinary support, with a low incidence of adverse events that are generally mild and manageable. PR confers clinically meaningful benefits in CRF, muscle strength and endurance, activity capacity and participation, and health-related QoL, whereas improvements in lung function are relatively modest. Functional gains appear to be predominantly mediated by peripheral adaptations, including enhancements in mitochondrial function, oxygen utilization efficiency, and neuromuscular performance. Current evidence supporting these benefits is largely derived from studies evaluating PR during the post-LTx recovery phase, while data on structured pre-LTx PR remain more limited and warrant further investigation. These findings underscore the importance of integrating PR as an essential component of both short- and long-term management in LTx recipients and provide a rationale for the development of standardized clinical protocols and future research aimed at optimizing rehabilitation strategies.

ACKNOWLEDGEMENTS

The authors would like to thank the Faculty of Medicine, Universitas Padjadjaran for academic support during the preparation of this manuscript and Dr. Hasan Sadikin General Hospital for the opportunity to conduct this review.