Journal of Cardiac and Pulmonary Rehabilitation
Open Access

Cardiac rehabilitation; Exercise training; Heart surgery; Functional recovery; Cardiovascular health; Post-surgical recovery; Exercise prescription; Physical fitness; Heart failure; Comorbidities; Rehabilitation protocols; Exercise modalities; Multidisciplinary care..

Introduction

Cardiac surgery, whether due to coronary artery disease, valve replacement, or heart transplant, is a pivotal event in the treatment of individuals with severe cardiovascular conditions. While surgical intervention is essential for saving lives and improving heart function, recovery after heart surgery is a multifaceted process that demands more than just medical management. The role of cardiac rehabilitation (CR), particularly exercise training, is now well-recognized as a cornerstone of effective recovery. Exercise training has become a standard component of post-surgical care, offering significant benefits in improving functional capacity, enhancing cardiovascular health, and reducing the risk of future cardiac events [1, 2].

Exercise training in cardiac rehabilitation is designed to help patients regain strength, endurance, and mobility after surgery. It involves a carefully supervised, progressive exercise regimen tailored to the individual's health status, physical limitations, and surgical outcomes. The focus is not only on improving physical fitness but also on addressing psychological well-being, which can be compromised after a major cardiac event. Structured exercise regimens can mitigate anxiety, depression, and stress, which are common in patients recovering from heart surgery.

The physiological benefits of exercise training are well-documented. Regular physical activity enhances myocardial oxygen consumption, improves endothelial function, increases exercise tolerance, and strengthens the heart muscle. It also plays a critical role in improving autonomic balance, reducing inflammation, and optimizing blood circulation, all of which are key factors in the recovery process after heart surgery. Moreover, exercise has been shown to reduce the incidence of postoperative complications such as deep vein thrombosis (DVT), infections, and pulmonary embolism, by promoting circulation and mobility [3].

Beyond the immediate postoperative recovery, exercise training contributes to long-term outcomes by improving cardiovascular risk factors such as hypertension, hyperlipidemia, and diabetes. These comorbidities are common in individuals undergoing heart surgery and can significantly impair recovery and contribute to the development of further cardiovascular events. By incorporating exercise into rehabilitation programs, patients can better manage these risk factors and improve their overall prognosis.

However, the implementation of exercise training in cardiac rehabilitation is not without challenges. Patient variability—based on age, comorbidities, the type of surgery, and the severity of cardiovascular disease—requires individualized exercise prescriptions. Overtraining or inappropriate intensity levels can also present risks, such as the potential for cardiac arrhythmias, musculoskeletal injuries, or excessive fatigue. Therefore, a multidisciplinary approach, involving cardiologists, exercise physiologists, physical therapists, and nurses, is essential to ensure that exercise interventions are both safe and effective.

The American Heart Association (AHA) and other professional organizations emphasize the need for evidence-based guidelines for exercise training in cardiac rehabilitation. These guidelines suggest that exercise prescriptions should be based on functional capacity assessments, incorporating aerobic, resistance, and flexibility exercises to address the diverse needs of heart surgery patients. Such guidelines aim to optimize recovery while minimizing adverse outcomes [4].

This paper aims to review the role of exercise training in cardiac rehabilitation, examining its physiological benefits, the recommended exercise modalities, and the optimal prescription parameters for enhancing recovery. We will also discuss the challenges and clinical considerations involved in prescribing exercise, the importance of tailoring rehabilitation to the individual patient, and the growing role of technology in monitoring patient progress. By understanding the integral role of exercise training in the post-surgical recovery process, clinicians can provide more effective and personalized care, ultimately improving functional outcomes and quality of life for heart surgery patients.

Materials and Methods

This review aims to examine the role of exercise training in optimizing functional recovery after heart surgery, including its physiological mechanisms, effectiveness in improving patient outcomes, and best practices for clinical implementation. The materials and methods section outlines the process used to collect and analyze relevant research, providing a foundation for the subsequent discussion and recommendations.

Literature search strategy

A comprehensive literature search was conducted to identify studies, systematic reviews, and clinical guidelines related to exercise training in cardiac rehabilitation (CR) following heart surgery. Databases including PubMed, Scopus, Cochrane Library, and Google Scholar were searched for publications up to October 2023. The search terms used included "exercise training," "cardiac rehabilitation," "heart surgery," "postoperative recovery," "functional recovery," "exercise prescription," "cardiac rehabilitation guidelines," and "cardiovascular health outcomes." [5].

Inclusion criteria for studies were as follows

Peer-reviewed studies published between 2000 and 2023.

Studies involving adult patients who underwent heart surgery, such as coronary artery bypass grafting (CABG), valve replacement, or heart transplant.

Studies evaluating exercise training interventions as part of a cardiac rehabilitation program.

Clinical trials, systematic reviews, meta-analyses, and observational studies that assessed functional recovery, cardiovascular health, or postoperative complications in the context of exercise training  [ 6].

Exclusion criteria included

Studies involving non-cardiac surgery patients.

Articles not published in English.

Studies focusing on pre-surgical interventions or those that did not include exercise as a component of rehabilitation.

Data extraction and analysis

From the selected studies, relevant data on the types of exercise modalities, intensity and duration of exercise programs, outcome measures (such as functional capacity, cardiovascular risk factor improvements, quality of life), and clinical outcomes (e.g., mortality, rehospitalization rates) were extracted. We focused on studies that provided quantitative data and clear comparative outcomes between exercise training and non-exercise control groups [7].

The key outcome measures analyzed included

Exercise capacity: Changes in peak VO₂ (maximal oxygen uptake), 6-minute walk test distance, or exercise tolerance during cardiopulmonary exercise testing.

Cardiovascular risk factors: Improvements in blood pressure, cholesterol levels, and blood glucose.

Physical function: Gains in strength, flexibility, and overall physical activity levels.

Psychosocial outcomes: Changes in anxiety, depression, and quality of life using standardized tools such as the Hospital Anxiety and Depression Scale (HADS) and SF-36 Health Survey.

Clinical events: Rates of rehospitalization, major adverse cardiac events (MACE), and long-term survival.

Exercise modalities and prescription parameters

We reviewed and summarized the types of exercise interventions used in cardiac rehabilitation programs, specifically focusing on:

Aerobic exercise: Walking, cycling, and swimming, which are commonly incorporated into CR protocols.

Resistance training: Light to moderate strength training exercises targeting the upper and lower extremities.

Flexibility exercises: Stretching programs aimed at improving joint mobility and reducing muscle stiffness.

Balance and functional training: Exercises designed to improve coordination and functional independence, particularly in elderly patients or those with comorbidities [8].

For each type of exercise, we examined the intensity, duration, frequency, and progression of the programs. Parameters followed recommendations from American Heart Association (AHA) and American College of Cardiology (ACC) guidelines, which suggest a combination of moderate-intensity aerobic activity (e.g., 30-60 minutes per session, 3-5 days per week) and resistance training (2-3 days per week).

Quality assessment and bias risk

The quality of studies included in the review was assessed using established tools:

The Cochrane Risk of Bias Tool for randomized controlled trials (RCTs).

The Newcastle-Ottawa Scale for observational studies, which assesses study quality based on selection, comparability, and outcomes. Each study was rated as low, moderate, or high risk of bias, based on its methodology and reporting standards. Studies with low bias risk were prioritized for inclusion in the synthesis of findings [9].

Statistical methods

Where applicable, data were synthesized using meta-analysis to calculate pooled effect sizes for the primary outcome measures (e.g., exercise capacity, cardiovascular risk factors, and quality of life). If data were not suitable for meta-analysis due to heterogeneity, qualitative synthesis was used to summarize findings across studies. Statistical analysis was conducted using RevMan (Cochrane Collaboration) or R software, and significance was considered at a p-value of <0.05.

Ethical considerations

This review relied on previously published studies, and no new patient data were collected. Therefore, ethical approval was not required. The review adhered to ethical standards by ensuring that only high-quality, peer-reviewed studies were included, and the analysis was conducted in a transparent and unbiased manner.

Limitations

Despite the rigorous search strategy, limitations of the review include potential heterogeneity in exercise interventions and outcome measures across the included studies. Variations in study designs, patient populations, and rehabilitation protocols may have influenced the generalizability of the findings. Additionally, some studies lacked long-term follow-up, which limits conclusions about the sustained effects of exercise training on functional recovery post-surgery [10].

Discussion

Exercise training is a cornerstone of cardiac rehabilitation (CR) programs, particularly in the context of recovery after heart surgery. The evidence reviewed highlights the significant role exercise plays in improving functional recovery, cardiovascular health, and overall well-being for heart surgery patients. This section discusses the key findings, challenges, and clinical implications of integrating exercise training into postoperative care, emphasizing its importance in optimizing both short- and long-term outcomes.

The physiological benefits of exercise are well-established. Studies consistently demonstrate that exercise training improves aerobic capacity, enhances muscular strength, and increases endurance in heart surgery patients. One of the most notable outcomes is the improvement in functional capacity, often assessed through tools such as the 6-minute walk test or peak VO₂. These gains not only contribute to improved physical fitness but also support the ability to return to daily activities, which is a critical factor in the rehabilitation process. Patients who engage in regular exercise show enhanced ability to manage daily tasks, which significantly improves their quality of life.

Furthermore, exercise training is associated with reductions in cardiovascular risk factors such as elevated blood pressure, cholesterol, and blood glucose levels. These improvements are particularly relevant in heart surgery patients, many of whom have comorbidities like hypertension and diabetes, which can hinder recovery and increase the risk of subsequent cardiovascular events. Exercise has a profound effect on reducing the burden of these conditions, contributing to long-term cardiovascular health and reducing the likelihood of rehospitalization or recurrence of heart disease.

Psychologically, exercise has been shown to alleviate common symptoms of anxiety and depression that frequently accompany heart surgery. Patients recovering from major cardiac events often experience emotional distress, which can hinder their motivation to participate in rehabilitation. The inclusion of exercise not only boosts physical health but also helps reduce psychosocial stress, providing patients with a sense of empowerment and control over their recovery. Mind-body interactions during exercise, particularly in group settings, foster a sense of community and support, which is also an important aspect of CR programs.

In addition to these benefits, exercise training enhances vascular health, improves autonomic regulation, and strengthens the cardiopulmonary system. Evidence suggests that regular physical activity promotes endothelial function, improves blood flow, and reduces systemic inflammation, all of which are essential for recovery following heart surgery. These physiological adaptations play a role in reducing postoperative complications such as deep vein thrombosis and pulmonary embolism, which can arise from immobility during recovery.

However, the success of exercise-based CR programs is highly dependent on individualization. Patients recovering from heart surgery vary widely in terms of age, comorbid conditions, surgical outcomes, and baseline fitness levels. This variability necessitates personalized exercise prescriptions, considering factors such as the type of heart surgery performed, the presence of any complications, and the patient's pre-surgical fitness status. For instance, while aerobic exercise like walking or cycling is typically emphasized, resistance training may be more beneficial for patients with low muscle mass or those at risk for sarcopenia. Similarly, flexibility and balance training may be prioritized in older adults or individuals who have undergone major procedures like heart transplants.

The optimal prescription of exercise—regarding frequency, duration, and intensity—remains a topic of ongoing research. Current guidelines recommend a mix of moderate-intensity aerobic activity (e.g., 30–60 minutes per session) and strength training (2-3 days per week). However, individual tolerance and response to exercise vary, and programs must be adjusted based on continuous monitoring of patients' cardiovascular status. Advanced monitoring technologies, such as wearable fitness trackers and telemedicine, are increasingly being integrated into CR programs, providing real-time data on heart rate, blood pressure, and physical activity levels. These technologies offer the potential for more accurate exercise prescriptions and more personalized care.

Despite the overwhelming evidence supporting the benefits of exercise training, there are challenges to implementation. One of the primary barriers is patient adherence. Post-surgical patients, particularly those with elderly or fragile health, may experience physical or psychological barriers to engaging in regular exercise. These include fatigue, pain, or fear of exacerbating heart issues. It is crucial for healthcare providers to offer motivational support, education, and clear communication regarding the safety and importance of exercise in recovery. Incorporating family support and community-based programs may also enhance adherence and long-term success.

Another challenge lies in the variability of rehabilitation programs across different healthcare settings. While exercise is a well-established component of cardiac rehabilitation in many countries, access to supervised rehabilitation programs is often limited, especially in low-resource settings or for patients living in rural areas. The disparity in access to CR highlights the need for broader policy changes to ensure equitable availability of evidence-based rehabilitation for all heart surgery patients.

Conclusion

Exercise training is a fundamental component of cardiac rehabilitation (CR) that plays a pivotal role in optimizing functional recovery following heart surgery. The evidence consistently supports the effectiveness of exercise in improving cardiovascular health, physical function, and psychosocial well-being in post-surgical patients. By enhancing aerobic capacity, muscular strength, and endurance, exercise training helps patients regain functional independence, enabling them to return to daily activities and significantly improving their quality of life.

In addition to these physical benefits, exercise training plays a crucial role in addressing the underlying cardiovascular risk factors, such as hypertension, hyperlipidemia, and diabetes, which are common in heart surgery patients. By improving these risk factors, exercise reduces the likelihood of future cardiac events, minimizing the risk of rehospitalization and improving long-term cardiovascular health outcomes. Furthermore, regular physical activity has profound positive effects on mental health, reducing symptoms of anxiety and depression that often accompany recovery from major cardiac procedures.

The integration of exercise training into post-surgical care is supported by established guidelines that advocate for a combination of aerobic and resistance training, tailored to the individual patient's needs and capabilities. Exercise prescriptions must be personalized based on factors such as the type of surgery, the patient's baseline fitness level, and any comorbid conditions. While structured, supervised programs are most effective, technology is increasingly being leveraged to support at-home or tele-rehabilitation, providing patients with greater access to CR, especially in rural or underserved areas.

Despite the clear benefits, challenges remain in the implementation of exercise-based CR programs. These challenges include patient adherence, variability in program accessibility, and the need for long-term follow-up to assess the sustained benefits of exercise training. To overcome these barriers, healthcare providers must foster patient motivation, provide education about the safety and effectiveness of exercise, and ensure equitable access to rehabilitation services.

Conflict of interest

None

Acknowledgment

None

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