Atrial fibrillation (AFib) is an irregular and often very rapid heart rhythm that originates in the heart’s upper chambers. This arrhythmia can lead to various symptoms and complications, including blood clots, stroke, and heart failure. Many individuals with AFib report experiencing weight gain, which can be a perplexing and concerning symptom. This article explores biological and lifestyle factors contributing to weight gain in people with AFib.
How AFib Symptoms Reduce Activity and Energy Expenditure
AFib symptoms often include fatigue, shortness of breath, heart palpitations, and dizziness. These physical manifestations can make even simple daily activities challenging, leading to a significant reduction in overall physical activity. When the heart beats erratically, it may not efficiently pump blood, reducing the body’s energy supply and making it harder to exercise. Consequently, individuals may become less inclined or able to engage in regular movement, impacting their calorie expenditure.
Reduced physical activity directly contributes to weight gain by creating an energy imbalance. If fewer calories are burned through movement than are consumed through diet, the excess energy is stored as fat. Decreased energy expenditure, combined with a slower metabolism, can lead to gradual weight gain. The physical limitations imposed by AFib symptoms are a direct and understandable pathway to weight gain for many individuals.
The Role of Inflammation and Hormonal Shifts
Atrial fibrillation is associated with systemic inflammation within the body. This inflammation can disrupt normal metabolic processes. Specifically, chronic inflammation may contribute to insulin resistance, where the body’s cells become less responsive to insulin, leading to altered fat storage. This can encourage the body to store more excess calories as fat, particularly around the abdomen.
Living with a chronic condition like AFib can also elevate stress levels, impacting stress hormones such as cortisol. Elevated cortisol levels are known to promote the accumulation of abdominal fat and can also influence appetite regulation. This hormonal imbalance can make weight management more challenging, as the body is signaled to store fat even if dietary intake remains consistent. The interplay between inflammation and stress hormones represents an internal biological pathway contributing to weight gain in AFib.
Medication-Related Contributions to Weight Gain
Certain medications for AFib or related heart conditions can have weight gain as a known side effect. Beta-blockers, for example, are a class of drugs often used to control heart rate and rhythm in AFib. Older types of beta-blockers, such as atenolol and metoprolol, are particularly associated with modest weight gain. Weight gain typically occurs within the first few months of starting the medication, averaging 2 to 4 pounds.
The mechanisms behind this medication-induced weight gain can vary. Some beta-blockers may slow down the body’s metabolic rate, meaning fewer calories are burned at rest. They can also cause a feeling of weariness or fatigue, which reduces the desire or capacity for physical activity, further contributing to decreased calorie expenditure. This effect of treatment is distinct from the direct symptoms of the condition itself.
Distinguishing Fluid Retention from True Weight Gain
Sometimes, the “weight gain” observed by individuals with AFib may not be an increase in body fat but rather due to fluid retention, also known as edema. When the heart’s pumping function is impaired, as can occur with AFib or associated heart conditions, the body may struggle to circulate blood efficiently. This can lead to excess fluid buildup in tissues, increasing overall body weight.
Signs of fluid retention often include noticeable swelling in the legs, ankles, and feet, and sometimes in the abdomen. The skin in affected areas might appear stretched or shiny, and pressing on it may leave a temporary indentation. Unlike fat gain, which typically occurs gradually, weight gain from fluid retention can happen quite rapidly, sometimes several pounds within a few days. It is important for medical professionals to differentiate between fluid retention and an increase in adipose tissue, as their underlying causes and management strategies differ.