Cardiopulmonary and Respiratory Physiotherapy Research Topics: 20 Evidence-Based Ideas for 2026

Last updated: August 2026

Choosing a good cardiopulmonary physiotherapy research topic starts with identifying an important unanswered clinical question, not simply choosing a disease or treatment and asking whether physiotherapy works.

Cardiopulmonary physiotherapy—also called cardiorespiratory physiotherapy or respiratory physiotherapy—includes rehabilitation for people with respiratory and cardiovascular conditions, as well as critically ill patients whose mobility, respiratory function or exercise capacity has been affected by illness.

The research ideas below were selected from gaps and uncertainties identified in recent systematic reviews, meta-analyses, network meta-analyses, randomized controlled trials and other high-quality contemporary evidence.

Many broad questions have already been answered. For example, there is little value in another small study simply asking whether pulmonary rehabilitation helps people with COPD or whether exercise benefits people with heart failure.

The more useful questions increasingly concern:

the optimal exercise dose;
which patients respond best;
which rehabilitation components are actually necessary;
how treatment should be personalised;
which patients need supervision;
home, hybrid and telerehabilitation models;
long-term adherence and maintenance;
airway-clearance treatment selection;
exercise in complex or frail patients;
activity and participation rather than impairment alone;
cost-effectiveness and implementation in real clinical services.

These topics can be adapted for a physiotherapy thesis, dissertation, research proposal or clinical research project.

COPD and Pulmonary Rehabilitation Research Topics

1. Which People With COPD Need a Personalised Pulmonary Rehabilitation Programme?

Research topic idea:
Personalised Versus Standardised Pulmonary Rehabilitation in COPD: Can Comorbidities, Baseline Function and Symptom Burden Be Used to Improve Treatment Response?

Why this is still a research gap:
Pulmonary rehabilitation is clearly beneficial at a population level, but individual response varies considerably.

A large 2026 real-world study involving 922 people with COPD found that only around half achieved clinically meaningful improvement following pulmonary rehabilitation, and fewer maintained those improvements at one year. Age, baseline symptoms, lung function and functional capacity appeared to influence response.

At the same time, contemporary expert recommendations increasingly emphasise modifying exercise prescription when COPD coexists with cardiovascular disease, heart failure, diabetes, hypertension or sarcopenia.

Instead of asking whether pulmonary rehabilitation works, a more useful trial would ask whether selecting and progressing exercise according to a patient’s comorbidities and baseline phenotype produces better outcomes than a largely standardised programme.

Suggested design: Multicentre pragmatic stratified RCT comparing standard pulmonary rehabilitation with phenotype/comorbidity-tailored rehabilitation.

Evidence basis:
Van Raemdonck et al. Short- and Long-Term Responses to Pulmonary Rehabilitation in 922 Patients with COPD: A Real-World Database Study (2002-2019). Journal of Clinical Medicine. 2026. PMID: 41598731.

Machado et al. Tailored Exercise Prescription for People with COPD and Clinically Relevant Comorbidities: A Consensus Statement of the EXPERT Working Group and Experts in Pulmonary Rehabilitation. Sports Medicine. 2025. PMID: 41343041.

2. What Is the Optimal HIIT Protocol for COPD?

Research topic idea:
Optimising High-Intensity Interval Training in COPD: Interval Duration, Recovery Time, Intensity and Patient Selection

Why this is still a research gap:
High-intensity interval training (HIIT) may allow some people with COPD to accumulate substantial training at high workloads without requiring prolonged continuous effort.

A 2026 systematic review and meta-analysis comparing HIIT with moderate-intensity continuous training found different advantages across outcomes. HIIT showed benefits for six-minute walking performance and several muscle-function outcomes, while continuous training performed better for peak oxygen uptake.

However, the review concluded that further research is needed to identify optimal HIIT protocols.

The next question should therefore not be another simple HIIT-versus-continuous-training comparison. Researchers should determine the best combination of work interval, recovery interval, intensity and progression—and identify which patients are most likely to tolerate and benefit from it.

Suggested design: Multi-arm RCT comparing different HIIT prescriptions, stratified by COPD severity and exercise limitation.

Evidence basis:
Suzen & Demirel. High-intensity interval training versus moderate-intensity continuous training for COPD: a systematics review and meta-analysis. Physiotherapy Theory and Practice. 2026. PMID: 41995152.

Explore related research: Search PhysioKeys for HIIT and exercise prescription in COPD →

3. Which Telerehabilitation Model Works Best for COPD?

Research topic idea:
Synchronous, Hybrid and Low-Technology Home Pulmonary Rehabilitation in COPD: Which Model Produces the Best Long-Term Outcomes and Adherence?

Why this is still a research gap:
The important question is increasingly not whether pulmonary telerehabilitation works, but how it should be delivered.

A 2026 systematic review and meta-analysis of 17 RCTs involving 1,658 participants found that telerehabilitation could achieve exercise-capacity outcomes broadly comparable with centre-based rehabilitation.

However, remote programmes varied substantially. Digitally supported programmes with synchronous professional supervision appeared more consistent than low-technology home programmes.

Long-term evidence was also less convincing: improvements in exercise capacity did not consistently translate into sustained increases in everyday physical activity.

Future research should compare specific delivery models rather than treating every form of “telerehabilitation” as the same intervention.

Suggested design: Pragmatic three-arm RCT comparing synchronous telerehabilitation, hybrid rehabilitation and minimally supervised home rehabilitation, with 12-month follow-up.

Evidence basis:
Li et al. Comparing Pulmonary Telerehabilitation and Center-Based Pulmonary Rehabilitation for Effectiveness and Adherence in Chronic Obstructive Pulmonary Disease: Systematic Review and Meta-Analysis of Randomized Controlled Trials. Journal of Medical Internet Research. 2026. PMID: 41996654.

Explore related research: Search PhysioKeys for pulmonary telerehabilitation in COPD →

4. Which Patients With COPD Benefit Most From Home Inspiratory Muscle Training?

Research topic idea:
Personalised Home-Based Inspiratory Muscle Training in COPD: Dose, Device Type and Baseline Inspiratory Muscle Weakness

Why this is still a research gap:
Inspiratory muscle training is relatively easy to deliver at home, but the optimal method and patient population remain uncertain.

A 2025 randomized trial compared a test-of-incremental-respiratory-endurance approach, conventional threshold IMT and sham training over an extended programme.

The novel training approach produced greater gains in inspiratory muscle performance, but the study was modest in size and adherence fell during the unsupervised period.

A larger study could answer several clinically useful questions simultaneously: Do people with objectively measured inspiratory muscle weakness benefit more? What is the minimum effective dose? How much supervision is necessary? And do gains in respiratory-muscle performance translate into less dyspnoea and better activity?

Suggested design: Multicentre RCT stratified by baseline inspiratory muscle strength, with objective adherence monitoring.

Evidence basis:
Dosbaba et al. Long-Term Efficacy of Novel and Traditional Home-Based, Remote Inspiratory Muscle Training in COPD: A Randomized Controlled Trial. Journal of Clinical Medicine. 2025. PMID: 40943858.

Explore related research: Search PhysioKeys for inspiratory muscle training in COPD →

Bronchiectasis Physiotherapy Research Topics

5. Which Airway Clearance Technique Works Best During a Bronchiectasis Exacerbation?

Research topic idea:
Personalised Airway Clearance During Bronchiectasis Exacerbations: ACBT, Oscillating PEP or Exercise With Huffing

Why this is still a research gap:
Airway clearance is a core component of bronchiectasis physiotherapy, but there is surprisingly little high-quality evidence telling clinicians which technique should be used for a particular patient.

A 2026 RCT compared active cycle of breathing techniques (ACBT), oscillating positive expiratory pressure and walking with huffing during hospitalisation for a bronchiectasis exacerbation.

ACBT and exercise with huffing produced broadly similar short-term improvements in sputum clearance and health-related quality of life. Longer-term exacerbation results were exploratory and affected by loss to follow-up.

Instead of looking for one universal “best” technique, future studies could investigate whether treatment selection according to sputum volume, breathlessness, fatigue, patient preference and ability to self-manage produces better adherence and outcomes.

Suggested design: Multicentre pragmatic RCT with preference/responder analysis and 6–12 month exacerbation follow-up.

Evidence basis:
Phillips et al. Active Cycle of Breathing Technique Versus Oscillating Positive Expiratory Pressure Therapy Versus Exercise With Huffing During an Exacerbation of Bronchiectasis: A Randomised, Controlled Trial. Respirology. 2026. PMID: 42155584.

6. Can Home Pulmonary Rehabilitation Reduce Exacerbations in Bronchiectasis?

Research topic idea:
Long-Term Home-Based Pulmonary Rehabilitation in Bronchiectasis: Effects on Exercise Capacity, Physical Activity and Exacerbations

Why this is still a research gap:
Pulmonary rehabilitation is recommended for people with bronchiectasis who have impaired exercise capacity or breathlessness, but the evidence base remains much smaller than in COPD.

A 2025 single-centre RCT reported improvements in quality of life and other clinical outcomes after a home-based bronchiectasis rehabilitation programme.

That is encouraging, but a single-centre study is not enough to define an optimal rehabilitation pathway for a heterogeneous disease.

A larger study should determine whether benefits persist, whether rehabilitation meaningfully changes daily physical activity and exacerbation frequency, and whether treatment response differs in patients with coexisting COPD or different bronchiectasis phenotypes.

Suggested design: Multicentre pragmatic RCT with 12-month exacerbation and objectively measured physical-activity outcomes.

Evidence basis:
Min et al. Role of home-based pulmonary rehabilitation programs for disease progression and quality of life in patients with stable bronchiectasis: a single-center RCT. Frontiers in Medicine. 2025. PMID: 40740957.

Explore related research: Search PhysioKeys for pulmonary rehabilitation in bronchiectasis →

Interstitial Lung Disease and Pulmonary Fibrosis Research Topics

7. Does CPET-Guided Exercise Prescription Improve Pulmonary Rehabilitation in ILD?

Research topic idea:
Cardiopulmonary Exercise Test-Guided Versus Standard Exercise Prescription in Interstitial Lung Disease

Why this is still a research gap:
Interstitial lung disease creates a particularly difficult exercise-prescription problem because exertional dyspnoea and oxygen desaturation can substantially limit training.

A 2025 systematic review identified 11 studies involving only 321 participants examining CPET-derived, tailored pulmonary rehabilitation. Only three were randomized trials.

Improvements were reported in peak oxygen uptake and work rate, but interventions were heterogeneous and follow-up was often short.

The authors specifically identified the need for standardised methods, consistent reporting and longer-term follow-up.

A direct trial could determine whether the added complexity and cost of CPET-guided prescription actually produces better clinical outcomes than careful prescription based on standard field tests and symptoms.

Suggested design: Multicentre RCT comparing CPET-guided rehabilitation with guideline-based standard prescription.

Evidence basis:
Bowhay et al. Utilisation of cardiopulmonary exercise testing for tailored pulmonary rehabilitation in people with interstitial lung diseases: A systematic review. Clinical Rehabilitation. 2025. PMID: 41168676.

Explore related research: Search PhysioKeys for CPET-guided pulmonary rehabilitation in ILD →

8. Can Remote Monitoring Make Home Pulmonary Rehabilitation Sustainable in IPF?

Research topic idea:
Long-Term Remotely Monitored Home Pulmonary Rehabilitation in Idiopathic Pulmonary Fibrosis

Why this is still a research gap:
Home-based rehabilitation is attractive in idiopathic pulmonary fibrosis because travelling repeatedly to a centre can become increasingly difficult as the disease progresses.

A 2026 RCT tested a remotely monitored home programme using activity/heart-rate monitoring and pulse oximetry.

The study showed excellent completion and adherence and meaningful improvement in moderate-to-vigorous physical activity, but only 29 participants were randomised and the intervention lasted 12 weeks.

The next question is whether this model remains effective and safe across larger and more diverse IPF populations, longer periods and different stages of disease, particularly when oxygen desaturation or functional decline progresses.

Suggested design: Multicentre RCT with 12-month follow-up, safety monitoring and health-economic analysis.

Evidence basis:
Child et al. Remotely Monitored Home-based Pulmonary Rehabilitation in Idiopathic Pulmonary Fibrosis: Results of a Randomized Controlled Trial. Archives of Physical Medicine and Rehabilitation. 2026. PMID: 42532213.

Pulmonary Hypertension Research Topics

9. What Is the Optimal Exercise Programme for Pulmonary Arterial Hypertension?

Research topic idea:
Aerobic, Resistance and Breathing Training in Pulmonary Arterial Hypertension: A Head-to-Head Trial of Exercise Components and Dose

Why this is still a research gap:
Supervised exercise is increasingly accepted for clinically stable pulmonary arterial hypertension, but clinicians still have limited evidence for choosing between exercise components.

A 2026 network meta-analysis included 16 trials and 644 participants. Different combinations of aerobic, resistance and breathing training produced promising signals for different outcomes.

However, evidence certainty was generally low or very low, active-versus-active comparisons were limited, and the authors cautioned against interpreting treatment rankings as proof of superiority.

They specifically called for larger, subtype-stratified trials with standardised exercise prescriptions, harmonised safety reporting and longer follow-up.

Suggested design: Multicentre active-comparator RCT stratified by pulmonary-hypertension subtype and functional class.

Evidence basis:
Hua et al. Effects of different exercise-based rehabilitation programs in adults with pulmonary arterial hypertension and related pulmonary hypertension populations: a systematic review and network meta-analysis. BMC Sports Science, Medicine and Rehabilitation. 2026. PMID: 42421065.

Asthma Physiotherapy Research Topics

10. Which Patients With Asthma Actually Benefit From Rehabilitation?

Research topic idea:
Phenotype-Specific Pulmonary Rehabilitation in Adults With Asthma: Exercise, Breathing Retraining and Combined Rehabilitation

Why this is still a research gap:
Rehabilitation interventions for asthma include exercise, breathing retraining and combined programmes, but the evidence remains difficult to translate into practice.

A 2025 systematic review evaluated 36 randomized trials and found substantial heterogeneity between interventions and outcomes. Overall certainty was low or very low, preventing firm conclusions about several rehabilitation approaches.

This creates a strong opportunity to move away from studies combining all adults with asthma into one group.

Future research could identify whether rehabilitation works differently in people with severe asthma, dysfunctional breathing, obesity, low fitness, high anxiety related to breathlessness or exercise avoidance.

Suggested design: Phenotype-stratified RCT comparing tailored rehabilitation with usual asthma management.

Evidence basis:
Zampogna et al. Effectiveness of Rehabilitation Interventions in Adults With Asthma: A Systematic Review and Meta-analysis. American Journal of Physical Medicine and Rehabilitation. 2025. PMID: 38958276.

Cystic Fibrosis Physiotherapy Research Topics

11. Can Exercise Replace Some Traditional Airway Clearance Sessions in Cystic Fibrosis?

Research topic idea:
Exercise as an Airway Clearance Technique in Cystic Fibrosis: A Long-Term Multicentre Trial of Safety, Efficacy, Treatment Burden and Cost

Why this is still a research gap:
This is particularly relevant as modern cystic fibrosis treatment changes disease burden and raises questions about how traditional physiotherapy routines should evolve.

A 2026 randomized pilot trial tested daily exercise as an airway clearance technique (ExACT) in people with CF receiving elexacaftor/tezacaftor/ivacaftor.

Participants allocated to ExACT stopped their other airway-clearance techniques during the 28-day intervention. The approach appeared feasible and safe in the pilot study.

Crucially, the authors recommended progression to a definitive longer-term multicentre trial evaluating safety, efficacy and cost-effectiveness.

That makes this unusually direct as a research recommendation.

Suggested design: Multicentre non-inferiority RCT with pulmonary exacerbations, lung function, treatment burden, adherence and cost-effectiveness outcomes.

Evidence basis:
Urquhart et al. Safety, feasibility and efficacy of exercise as an airway clearance technique in cystic fibrosis: a randomised pilot feasibility trial. Thorax. 2026. PMID: 41033804.

Long COVID Physiotherapy Research Topics

12. Should Long COVID Rehabilitation Be Prescribed According to Symptom Phenotype?

Research topic idea:
Phenotype-Stratified Physiotherapy for Long COVID: Exercise-Based Rehabilitation Versus Pacing and Energy-Conservation Pathways

Why this is still a research gap:
Long COVID is too heterogeneous for a single rehabilitation prescription.

A 2026 systematic review and meta-analysis of 10 randomized trials found that exercise programmes could improve several cardiopulmonary and functional outcomes in people with post-COVID condition.

However, this should not be interpreted to mean that progressive exercise is appropriate for every person with Long COVID.

Contemporary physiotherapy guidance recommends specific assessment for fatigue, post-exertional malaise/post-exertional symptom exacerbation, orthostatic intolerance, respiratory symptoms and other red flags before selecting rehabilitation.

This creates an important next research question: do outcomes improve when patients are stratified before treatment, with exercise-based rehabilitation offered to appropriate patients and pacing/energy-management strategies prioritised when post-exertional symptom exacerbation is present?

Suggested design: Pragmatic stratified trial comparing phenotype-guided rehabilitation with non-stratified usual rehabilitation. Patients with post-exertional symptom exacerbation should not simply be randomised to forced progressive exercise.

Evidence basis:
Khuna et al. Effects of exercise programs on cardiopulmonary function and signs and symptoms in patients with post-COVID-19 condition: a systematic review and meta-analysis. Frontiers in Medicine. 2026. PMID: 41924744.

Reeves et al. Physiotherapy management of Long-COVID: an evidence-based approach. Brazilian Journal of Physical Therapy. 2026. PMID: 42320154.

ICU and Critical Care Physiotherapy Research Topics

13. Should ICU Mobilisation Dose Be Different for Frail and Non-Frail Patients?

Research topic idea:
Age- and Frailty-Specific Mobility Dose in Mechanically Ventilated ICU Patients

Why this is still a research gap:
“Early mobilisation” is often discussed as though it were one intervention, but mobilisation includes several variables: when it starts, how often it occurs, how intense it is and how much total activity the patient completes.

A 2025 multicentre prospective study included 422 mechanically ventilated patients across 22 ICUs.

The rehabilitation variables associated with later independence differed according to age and frailty. For example, intensity and earlier mobilisation appeared particularly relevant in some groups, while frequency and duration appeared more important among frail older adults.

These observational results cannot establish causality, but they strongly support testing individualised mobility prescriptions instead of one standard ICU dose.

Suggested design: Multicentre adaptive or stratified RCT according to age and Clinical Frailty Scale.

Evidence basis:
Watanabe et al. Impact of mobility dose levels on functional outcomes in individualised patients with critical illness: A multicentre prospective observational cohort study in Japan. Clinical Rehabilitation. 2025. PMID: 41252336.

Explore related research: Search PhysioKeys for ICU mobilisation dose and frailty →

14. Who Benefits From Exercise Rehabilitation After ICU Discharge?

Research topic idea:
Personalised Post-ICU Exercise Rehabilitation: Identifying Responders and the Optimal Delivery Model After Critical Illness

Why this is still a research gap:
Recovery does not end when somebody leaves the ICU.

A systematic review and meta-analysis of 14 randomized trials involving 1,259 critical-illness survivors found that post-discharge exercise rehabilitation could improve aerobic capacity and the physical component of health-related quality of life, with some evidence for improvement in depression.

However, ICU survivors are extremely heterogeneous. Some leave hospital almost independent, while others have profound weakness, respiratory limitations, cognitive problems and post-intensive-care syndrome.

Rather than another broad exercise-versus-usual-care trial, research should determine who requires structured rehabilitation, what intensity is appropriate, and whether supervised, home or hybrid programmes work best for different recovery profiles.

Suggested design: Stratified pragmatic RCT using discharge mobility/function to assign rehabilitation pathways.

Evidence basis:
Cazeta et al. Effects of exercise interventions on functioning and health-related quality of life following hospital discharge for recovery from critical illness: A systematic review and meta-analysis of randomized trials. Clinical Rehabilitation. 2024. PMID: 38556253.

Heart Failure and Cardiac Rehabilitation Research Topics

15. What Is the Best Exercise Modality for HFpEF?

Research topic idea:
Head-to-Head Exercise Training in Heart Failure With Preserved Ejection Fraction: Aerobic, Resistance, Interval and Inspiratory Muscle Training

Why this is still a research gap:
Heart failure with preserved ejection fraction (HFpEF) is an important rehabilitation population, but exercise prescription remains much less certain than clinicians would ideally like.

A 2026 systematic review and network meta-analysis included 12 RCTs and 602 participants.

Several exercise modalities showed potential benefits for exercise-capacity outcomes, including continuous aerobic exercise, moderate-intensity aerobic training and inspiratory muscle training.

However, the certainty of evidence was rated very low for every outcome.

The network therefore cannot confidently tell clinicians which programme to prescribe.

Direct active-versus-active trials with standardised training doses are needed.

Suggested design: Multicentre head-to-head RCT comparing two or more clearly defined exercise prescriptions, ideally with CPET-based outcomes and long-term clinical follow-up.

Evidence basis:
Henríquez-Jurado et al. Effectiveness of different exercise modalities in Heart Failure with preserved Ejection Fraction. A systematic review with network meta-analysis. Brazilian Journal of Physical Therapy. 2026. PMID: 41997085.

Explore related research: Search PhysioKeys for exercise rehabilitation in HFpEF →

16. How Much Resistance Training Should Be Added to Aerobic Training in Heart Failure?

Research topic idea:
Optimising Combined Resistance and Aerobic Training in Heart Failure: Dose, Sex and Ejection-Fraction Phenotype

Why this is still a research gap:
A 2026 systematic review and meta-analysis found that combining muscle-strengthening exercise with aerobic training produced greater improvements in cardiorespiratory fitness, six-minute walk distance and upper-body strength than aerobic training alone in HFrEF.

However, the evidence base had a major representation problem: 89% of included participants had reduced ejection fraction and only 17% were women.

The authors specifically concluded that further evidence is needed in HFpEF.

A useful next study would therefore determine the optimal amount of resistance training while intentionally recruiting women and people across heart-failure phenotypes.

Suggested design: Dose-matched RCT comparing aerobic training alone with different aerobic/resistance combinations, stratified by sex and ejection fraction.

Evidence basis:
Terada et al. Combined strength and aerobic training vs. aerobic training alone in patients with heart failure: A systematic review and meta-analysis. Journal of Sport and Health Science. 2026. PMID: 41881310.

17. What Is the Optimal Cardiac Rehabilitation Programme for Frail Older Adults With Heart Failure?

Research topic idea:
Frailty-Adapted Exercise Rehabilitation in Older Adults With Heart Failure

Why this is still a research gap:
Traditional cardiac rehabilitation programmes may not be designed around frailty.

A 2026 systematic review found only six intervention studies specifically evaluating exercise in frail older adults with heart failure.

Results were encouraging: exercise was associated with improvements across frailty, physical function, activity and quality-of-life outcomes.

However, interventions varied considerably in modality and duration, and the evidence base remains small.

This population may require slower progression, greater resistance/functional training, balance work, symptom-guided intensity and different delivery models than younger, non-frail cardiac rehabilitation populations.

Suggested design: Multicentre RCT comparing frailty-adapted multicomponent rehabilitation with conventional cardiac rehabilitation.

Evidence basis:
Sáez-Nieto et al. Effects of exercise training on frail older adults with heart failure: a systematic-review. Frontiers in Aging. 2026. PMID: 41969362.

18. How Can Cardiac Rehabilitation Participation Be Increased After Myocardial Infarction?

Research topic idea:
Patient-Centred Rehabilitation Choice After Myocardial Infarction: Can Tailored Counselling Plus Centre-Based and Telehealth Options Increase Participation?

Why this is still a research gap:
An intervention cannot benefit patients who never participate.

A 2026 prospective analysis of people following acute myocardial infarction found that approximately one in five did not participate in either centre-based or telehealth cardiac rehabilitation.

Non-participants tended to be older, and the most common reason was lack of interest or failure to recognise the need for rehabilitation.

Simply making telerehabilitation available therefore does not solve every participation barrier.

A useful study would test whether patient-centred counselling, shared decision-making and an explicit choice between centre, hybrid and remote pathways increases actual enrolment and completion—particularly among older adults.

Suggested design: Pragmatic randomized implementation trial using cardiac-rehabilitation participation and completion as primary outcomes.

Evidence basis:
van Mierlo et al. Patient characteristics of non-participants and reasons for non-participation in cardiac (tele)rehabilitation—a prospective analysis. Frontiers in Rehabilitation Sciences. 2026. PMID: 42254476.

Cardiac Surgery Physiotherapy Research Topics

19. What Is the Optimal Inspiratory Muscle Training Protocol After CABG?

Research topic idea:
Dose and Timing of Inspiratory Muscle Training During Phase I and II Rehabilitation After Coronary Artery Bypass Grafting

Why this is still a research gap:
Inspiratory muscle training after CABG has enough evidence that another simple IMT-versus-no-IMT trial would be less informative.

A systematic review and meta-analysis of 15 studies found that IMT could improve exercise capacity and inspiratory-muscle strength and may reduce hospital length of stay during early rehabilitation.

However, evidence quality ranged from very low to moderate and several outcomes were affected by substantial risk of bias.

An important next step is to determine the best training intensity, timing, progression and patient-selection criteria, including whether patients with pre-existing inspiratory muscle weakness gain the most.

Suggested design: Multicentre dose-response RCT stratified according to preoperative inspiratory muscle strength.

Evidence basis:
Araújo et al. Inspiratory Muscle Training in Phase 1 and 2 Postoperative Cardiac Rehabilitation Following Coronary Artery Bypass Graft Surgery: Systematic Review With Meta-Analysis. Physical Therapy and Rehabilitation Journal. 2024. PMID: 38624192.

Explore related research: Search PhysioKeys for inspiratory muscle training after CABG →

20. How Early Should Patients Be Mobilised After Cardiac Surgery?

Research topic idea:
Mobilisation Within 24 Hours After Cardiac Surgery: Effects on Delirium, Functional Recovery and Length of Stay

Why this is still a research gap:
Early mobilisation following cardiac surgery is logical and commonly encouraged, but the optimal timing has not been established.

A 2026 randomized pilot study examined mobilisation within 24 hours following cardiac surgery.

Early mobilisation appeared safe and was associated with shorter delirium duration, although the study was small and did not demonstrate a clear statistically significant reduction in overall delirium incidence.

The authors specifically recommended testing these preliminary findings in larger multicentre trials.

Future studies should also determine whether earlier mobilisation improves walking independence, ICU length of stay, discharge destination and long-term physical function—not delirium alone.

Suggested design: Multicentre RCT comparing protocolised mobilisation within 24 hours with current usual-care timing.

Evidence basis:
Xu et al. The effect of early mobilization of post-cardiac surgery patients on delirium: a pilot study. European Journal of Physical and Rehabilitation Medicine. 2026. PMID: 41706053.

Explore related research: Search PhysioKeys for early mobilisation after cardiac surgery →

What Types of Research Work Well in Cardiopulmonary Physiotherapy?

The best study design depends on the question.

Dose-Response Trials

Useful when treatment already works but the optimal amount is uncertain.

Example: Comparing different HIIT interval prescriptions in COPD.

Active-Comparator RCTs

Particularly valuable when multiple accepted treatments already exist.

Example: Comparing ACBT with oscillating PEP for bronchiectasis rather than comparing airway clearance with no treatment.

Stratified and Personalised Rehabilitation Trials

Useful in heterogeneous conditions where the same programme is unlikely to suit everybody.

Example: Stratifying Long COVID rehabilitation according to post-exertional symptom exacerbation.

Non-Inferiority Trials

Useful when a simpler, cheaper or less burdensome intervention may achieve similar outcomes.

Example: Determining whether exercise can replace selected conventional airway-clearance sessions in cystic fibrosis.

Pragmatic and Implementation Trials

Useful when an intervention has efficacy evidence but participation or real-world delivery remains poor.

Example: Testing whether offering patients a choice of centre-based, hybrid and tele-cardiac rehabilitation improves participation.

Prognostic and Responder Studies

Useful for determining who benefits from an established treatment.

Example: Identifying which patients with COPD maintain clinically meaningful gains one year after pulmonary rehabilitation.

Qualitative and Mixed-Methods Research

Important when treatment burden, adherence, patient preferences or service delivery influence outcomes.

Example: Understanding why people decline cardiac rehabilitation after myocardial infarction.

Health-Economic Research

Increasingly important as rehabilitation moves into home and digital environments.

Example: Comparing the cost-effectiveness of remotely monitored pulmonary rehabilitation with centre-based rehabilitation.

How to Turn One of These Ideas Into a Cardiopulmonary Physiotherapy Thesis

A research topic is only the starting point.

Before finalising your question:

Define the population precisely.
“Respiratory patients” is usually far too broad. COPD severity, bronchiectasis phenotype, ILD subtype, heart-failure phenotype, frailty and ICU status can all materially change the research question.
Define the intervention properly.
Exercise research should report frequency, intensity, time, type, volume and progression.
Measure the treatment actually completed.
Prescribing three sessions per week does not mean three sessions were performed.
Choose a clinically meaningful comparator.
When effective rehabilitation already exists, an active comparator is often more valuable than no treatment.
Prioritise patient-important outcomes.
Improvements in inspiratory pressure or VO₂ peak can be useful, but patients may care more about breathlessness, walking, exacerbations, independence and participation.
Consider longer-term outcomes.
A programme that improves a six-minute walk test at eight weeks but produces no lasting change in physical activity may have limited long-term impact.
Consider disease heterogeneity.
Cardiopulmonary populations frequently have multiple comorbidities, and the same exercise prescription may not be suitable for everyone.
Include safety outcomes where appropriate.
This is particularly important in pulmonary hypertension, ILD with exertional desaturation, critical illness, Long COVID and early cardiac rehabilitation.
Measure adherence and treatment burden.
A theoretically effective intervention is less useful if patients cannot sustain it.
Check feasibility.
A high-quality student project that can realistically recruit and retain enough participants is usually more valuable than an ambitious but underpowered study.

Before You Finalise Your Research Topic

Research gaps change as new trials and systematic reviews are published.

Before committing to a thesis or project, search the latest evidence to confirm that the question is still genuinely unanswered.

Look particularly at:

recent systematic reviews and meta-analyses;
randomized controlled trials published after those reviews;
limitations identified by review authors;
recommendations for future research;
ongoing trials that may answer your question before your project is completed.

You can use PhysioKeys to search current physiotherapy and rehabilitation research across respiratory, pulmonary, cardiac and critical-care conditions.

Search cardiopulmonary physiotherapy research on PhysioKeys →

A useful research project should not simply confirm that rehabilitation works. It should help us understand what to prescribe, how much to prescribe, who needs it, how to deliver it, and whether the benefits actually matter in everyday life.