Exercise-based cardiac rehabilitation lessens the severity, frequency, and recurrence of the most common form of irregular heart rhythm, atrial fibrillation, or AF for short, finds a pooled data analysis of the available research, published online in the British Journal of Sports Medicine.

It also improves general exercise capacity and mental health, without incurring any serious side effects, the findings show.

AF occurs when the heart’s upper chambers (atria) don’t contract properly and instead twitch, disrupting the electrical signals to the lower chambers (ventricles). Symptoms can include palpitations, chest pain, fatigue, dizziness, and shortness of breath.

AF is associated with a heightened risk of stroke and heart failure. An estimated 6–12 million people will develop it in the US by 2050 and nearly 18 million in Europe by 2060, note the researchers.

While current treatment is effective, the ability of patients to manage their condition themselves may help slow progression, maintain functional capacity, and minimize impact on their quality of life, they add.

Exercise-based cardiac rehabilitation includes exercise training alongside personalized lifestyle risk factor management, psychosocial intervention, medical risk management and health behavior education.

It’s used for patients who have had a heart attack, been diagnosed with heart failure, or who have had a stent fitted to improve blood flow to the heart, explain the researchers. But it’s not clear if this type of rehab is suitable for patients with AF, and it’s therefore not included in international AF treatment guidelines.

Previous systematic reviews on the subject, published in 2017 and 2018, provided inconclusive evidence for its broader benefits. But since then, several other relevant clinical trials have been published, so the researchers set out to update the evidence.

They scoured research databases for randomized clinical trials on the effects of exercise-based cardiac rehabilitation in patients with AF, published up to March 2024.

They found 20 relevant clinical trials carried out between 2006 and 2024 that involved 2039 patients, who were subsequently monitored for an average of 11 months. Ten trials were carried out in Europe, four in Asia, two in Australia, one each in Brazil, Canada, and Russia, and one in several countries.

Five trials assessed comprehensive exercise rehabilitation, which included educational and/or psychological components; the remainder assessed exercise only rehabilitation.

The exercise interventions ranged from eight to 24 weeks, involving one to seven weekly sessions of 15–90 minutes in length. Most trials included moderate intensity interventions, with only three looking at the impact of vigorous intensity. Most trials included only aerobic-based exercise training, although six included both aerobic and resistance-based cardiac rehab.

Pooled data analysis of the results showed that this type of rehab didn’t affect the relative risks of death from any cause (8% vs. 6% in the comparison group) or serious side effects (3% vs. 4%).

But compared with those in the comparison groups, it reduced symptom severity by 39%, frequency and length of AF episodes by 43% and 42%, respectively, and risk of recurrence by 32%.

It also significantly improved exercise capacity, as measured by maximal oxygen intake. The scores for the mental component of a health-related quality of life questionnaire also improved significantly, although this wasn’t the case for the physical component.

The effects were consistent, irrespective of type of AF, ‘dose’ of rehab, patient characteristics, or method of delivery.

The researchers acknowledge some limitations to their findings. Several trials lacked key methodological information, and those reporting the primary outcomes of interest were few. Most trials were relatively small and had a short monitoring period. The number of reported deaths and serious side effects was small, which substantially reduced the ability to reliably detect any true effect. And most participants were men.

Notwithstanding these caveats, the researchers suggest, “While improvements in traditional cardiovascular risk factors likely account for a substantial proportion of the benefit, additional mechanisms may directly impact AF burden and recurrence.

“Exercise training promotes favorable atrial remodeling, including reduced atrial stiffness and fibrosis, which may help limit [conditions favorable for AF], although further research is needed.”

They add, “Exercise training is known to have psychological benefits, including reductions in anxiety and depression, which are prevalent in individuals with AF and can exacerbate symptom perception.”

And they continue, “Collectively, these adaptations provide plausible mechanisms through which [exercise-based rehab] not only supports general cardiovascular health and well-being but also gives AF specific benefits, including reductions in AF recurrence post-treatment and improvements in self-reported AF burden and severity.”

They conclude, “AF management guidelines should reflect this updated evidence base by recommending [exercise-based cardiac rehabilitation] alongside drug and ablation therapies for patients with AF.”

In a linked editorial, expanding on the role of exercise in the treatment of AF, Drs. Sarandeep Marwaha and Sanjay Sharma of the Institute of Cardiovascular and Cell Sciences, London, say the findings “provide further compelling evidence that [exercise-based cardiac rehabilitation] significantly benefits patients with AF.”

They add, “Exercise is widely recognized as an important management tool, and it is crucial to highlight that it remains one of the most cost-effective, readily available, and manageable interventions for improving cardiovascular health.”

They continue, “Patients may fear that exercise can trigger AF episodes, especially those with underlying heart conditions, and clinicians will often underemphasize exercise guidance and exercise prescriptions due to uncertainty. However, most studies evaluating moderate exercise in patients with AF have demonstrated safety with a very low risk of adverse events.”

But they caution, “It is essential to highlight that while exercise is a powerful tool in managing AF, it is most effective when precisely tailored to individual factors, such as comorbidities, AF characteristics, functional status, psychological factors and the requirement for supervision or monitoring.”