Research Blog
Atrial fibrillation (AF) is the most common arrhythmia in clinical practice, characterized by uncoordinated electrical activity in the atria, leading to ineffective atrial contractions.
AF significantly increases the risk of mortality, stroke, and peripheral embolism. Its global incidence and prevalence are rising, affecting up to 37.5 million people.
Risk factors include advanced age, male gender, European descent, sedentary lifestyle, smoking, obesity, diabetes mellitus, obstructive sleep apnea, high blood pressure, heart failure, and myocardial infarction.
Symptoms vary in severity and may include palpitations, fatigue, shortness of breath, dizziness, and chest discomfort. Early detection and personalized treatment are crucial due to its diverse clinical presentation.
Physical activity
An unhealthy lifestyle is a recognized risk factor for atrial fibrillation (AF), and lifestyle changes are significant factors in AF management. Physical activity reduces AF risk by controlling modifiable factors such as hypertension and obesity, and it independently decreases the likelihood of AF onset.
Regular moderate-intensity physical activity—at least 500 MET-minutes per week—is recommended, as it significantly lowers AF incidence, particularly in females. Both moderate-to-vigorous intensity continuous training (MICT) and high-intensity interval training (HIIT) have shown positive effects in patients with persistent or permanent AF, improving quality of life, reducing symptoms, enhancing functional capacity, and increasing cardiorespiratory fitness.
Physical activity also offers neuroprotective benefits, reducing the risk of ischemic strokes and cognitive decline in AF patients. Therefore, encouraging regular physical exercise is crucial for both the prevention and management of AF, as well as for minimizing complications and improving overall patient well-being.
However, while physical activity is generally beneficial, it can also trigger atrial fibrillation (AF), especially in endurance athletes. High-intensity endurance exercises may cause structural and functional changes in the heart, such as increased vagal tone, enlargement of the left atrium, and pulmonary vein ectopy, leading to a higher frequency of premature atrial contractions that can trigger AF and potentially progress to permanent AF.
Smoking
Tobacco smoking is a leading avoidable cause of death and a significant risk factor for atrial fibrillation (AF). The harmful chemicals in cigarette smoke, including nicotine, carbon monoxide, and tar, contribute to cardiovascular disease directly.
Nicotine increases catecholamine levels, leading to higher blood pressure and heart rate, which are associated with an increased risk of AF. Smokers with AF have a higher risk of stroke and thromboembolism and often require anticoagulation therapy. Heat-not-burn tobacco products are not safer alternatives since they release the same harmful chemicals as conventional cigarettes. Studies have shown that both current and former smokers have a higher risk of developing AF compared to those who have never smoked, with no significant differences between genders. Even early exposure to secondhand smoke can increase the risk of AF later in life. The most effective strategy to reduce the risk of AF is to avoid smoking altogether.
Sleep
Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder, characterized by recurring episodes of apnea and hypopnea due to complete or partial collapse of the upper airway during sleep. Studies have found that individuals with OSA have a fourfold increased risk of developing AF compared to those without OSA. The mechanisms linking OSA to AF include hypoxia, intrathoracic pressure shifts, autonomic nervous system hyperactivity, systemic inflammation, and oxidative stress resulting from recurrent airway collapse during sleep.
OSA causes cycles of hypoxia and reoxygenation that activate proinflammatory pathways, leading to increased reactive oxygen species (ROS) formation and reduced nitric oxide levels. This results in systemic inflammation and oxidative stress, causing endothelial damage and a higher propensity for arrhythmias like atrial fibrillation (AF).
Elevated inflammatory markers such as C-reactive protein and IL-6 are observed in OSA patients, contributing to endothelial dysfunction and left atrial dilation—known contributors to AF.
Other sleep disturbances, including frequent awakenings, insomnia, and reduced REM sleep, are also associated with an increased risk of AF.
Pollution
Air pollution—including particulate matter, ozone, sulfur dioxide, nitrogen dioxide, and carbon monoxide—is emerging as a significant risk factor for atrial fibrillation. Elevated levels of these pollutants can trigger systemic inflammation, autonomic nervous system dysfunction, and structural remodeling of the heart muscle, leading to electrophysiological changes that increase the likelihood of AF.
Studies have demonstrated that short-term and long-term exposure to air pollution correlates with a higher incidence of AF, with the risk being more pronounced in males, older adults, individuals with higher body mass index, and those with hypertension.
Diet
Diet modification is fundamental in preventing cardiovascular diseases and managing AF. A nutritious, heart-healthy diet supports cardiovascular health by controlling risk factors such as hypertension, obesity, high cholesterol, and chronic inflammation—all of which contribute to AF.
A plant-based diet emphasizing vegetables, spinach, kale, onions, red cabbage, fruits, berries, grapes, apples, nuts, and whole grains can improve cardiovascular function and aid in weight management, potentially lowering AF risk.
Diet patterns like the Mediterranean diet, rich in fruits, vegetables, whole grains, healthy fats like extra virgin olive oil, fish, and 0.63 grams/day of marine-based omega-3 fatty acids, have been linked to a reduced risk of AF due to their anti-inflammatory and antioxidant properties.
Conversely, consuming fried, processed, and ultra-processed foods can exacerbate AF risk factors, and both very low and very high salt intake may increase AF incidence.
Coffee
The relationship between caffeine and AF is complex and not definitively established. Caffeine in coffee, tea, cola, and energy drinks influences the neurohormonal and sympathetic nervous systems.
Some studies suggest that high caffeine intake may increase the risk of AF, particularly at very high doses or in hypertensive patients, due to sympathetic overactivity and pro-arrhythmic effects.
Conversely, other research indicates a neutral or even protective effect, as caffeine antagonizes adenosine receptors, which can reduce atrial muscle contractility and decrease sinoatrial node activity.
Additionally, the antioxidants in coffee, including polyphenols, may help mitigate oxidative stress linked to AF. Individual responses to caffeine vary, and while no definitive conclusion exists, moderate consumption—up to 300 mg per day—is generally considered safe.
Alcohol
Alcohol has a multifaceted impact on atrial fibrillation (AF). Excessive alcohol consumption is independently associated with an increased risk of AF through both indirect and direct mechanisms.
Indirectly, ethanol induces oxidative stress and releases plasma fatty acids, leading to AF, particularly in individuals with existing cardiovascular diseases. Directly, alcohol shortens the atrial action potential, promoting the development of AF.
Both the amount and pattern of alcohol intake matter; heavy chronic consumption and acute binge drinking (known as the "holiday heart" phenomenon) can trigger AF episodes.
While moderate alcohol consumption has been linked to cardiovascular benefits, such as reduced risk of coronary artery disease due to compounds like resveratrol in red wine, even moderate intake may increase AF risk and contribute to hypertension and obesity. Therefore, alcohol is a crucial modifiable risk factor in the management of AF, and patients should be evaluated and advised individually.
New onset AF
Researchers have developed several risk scores to predict the risk of atrial fibrillation, including the Framingham AF risk score, the ARIC risk model, and the CHARGE-AF score, which consider factors like age, weight, blood pressure, heart failure, and comorbidities.
In 2023, Segan et al. introduced the HARMS2-AF lifestyle risk score, specifically designed to assess AF risk based on lifestyle factors. This score assigns points for hypertension, age, raised BMI (≥30 kg/m²), male sex, sleep apnea, smoking, and alcohol consumption, totaling up to 14 points. A score of 5 or higher is associated with a significantly increased risk of developing AF (with hazard ratios increasing with higher scores), indicating the need for significant lifestyle changes.
The HARMS2-AF tool helps identify individuals at elevated risk due to modifiable lifestyle factors, emphasizing the importance of lifestyle interventions in preventing AF.
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Optimal Takeaways
- Atrial fibrillation (AF) is a significant health concern, affecting about 2% of individuals under 65 and approximately 9% of those aged 65 and older.
- Lifestyle factors play a critical role in the development and management of AF.
- Key factors include physical activity, smoking, sleep disorders like obstructive sleep apnea, air pollution, and diet.
- Engaging in regular physical activity has been shown to reduce the incidence of AF and limit related complications.
- Smoking—both active and passive—increases the risk of AF, with traditional cigarettes and non-combustible tobacco products contributing to its pathogenesis.
- Sleep disorders not only elevate the risk of developing AF but also impair the effectiveness of antiarrhythmic therapies.
- Air pollution is a significant factor in AF development, with studies showing increased incidence regardless of exposure duration.
- A Mediterranean-style diet rich in fruits, vegetables, whole grains, nuts, and healthy fats like extra virgin olive oil and fish can help reduce AF risk.
- Avoiding ultra-processed foods and excess alcohol is vital to reducing AF risk.
- Moderate caffeine intake of up to 300 mg/day is generally considered safe and possibly protective for AF, while excess caffeine may exacerbate it.
- It is essential to provide patients with tailored dietary guidance based on their specific conditions and the severity of their AF.
- Early detection of these modifiable factors and prompt intervention should be integral in clinical practice.
- Incorporating lifestyle and dietary changes as preventive measures alongside existing arrhythmia treatments is essential.
Reference
Leszto, Klaudia et al. “Associations of Dietary and Lifestyle Components with Atrial Fibrillation.” Nutrients vol. 16,3 456. 5 Feb. 2024, doi:10.3390/nu16030456 This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
