What’s the link between obesity and irregular heartbeats?

You may have heard that being overweight or having obesity can put a strain on your heart and increase your risk for heart disease. But did you know that obesity can also increase your risk for another potentially dangerous heart condition called atrial fibrillation?

About one in five cases of atrial fibrillation may be caused by obesity, according to research cited in a scientific statement by the American Heart Association (AHA). And for every 5-unit increase in BMI, the risk of developing atrial fibrillation increases by about 29 percent. The AHA statement was published in the journal Circulation in 2021.

The CDC estimates that by 2030, about 12 million Americans will have atrial fibrillation, also called AFib or AF. It’s an irregular heart rhythm (also known as an arrhythmia) that develops when the upper chambers of your heart (the atria) quiver and beat out of sync so that blood cannot flow effectively to the lower chambers of your heart (the ventricles). When this happens, blood clots may form in your heart.

If these clots break off, they can travel to other parts of your body such as your brain. A clot that blocks an artery leading to the brain can cause a stroke. For this reason, many people with AFib take blood thinning medication to decrease their risk of clots. Untreated AFib is associated with a five-fold increased risk of stroke caused by blockage of a blood vessel leading to the brain.

Sometimes people can have episodes of occasional AFib, when the irregular heart rhythms come and go. If you have this type of AFib, it’s still important to see your healthcare provider (HCP) regularly about it, so that you can get the treatment you need. In some people, occasional AFib can progress to permanent AFib, when a regular heart rhythm can never be restored and medications are needed.

Having a BMI between 30 and 34.9 is associated with a 54 percent increased likelihood of progressing to permanent AFib. A BMI between 35.0 and 39.9 may increase this risk by 87 percent, according to the AHA statement.

Why does obesity increase the risk for AFib?

Researchers think obesity can increase the risk of AFib in a number of ways. Obesity can put a strain on the heart, resulting in changes to your heart’s structure that can interfere with the conduction of electrical signals that make your heart beat regularly. Fat tissue can also accumulate around and within your heart and can interfere with these electrical signals.

Obesity also contributes to other conditions that can affect your heart, including abnormal cholesterol levels, type 2 diabetes, high blood pressure, and sleep disorders like sleep apnea. It can increase your risk for hardening of the arteries around the heart (coronary artery disease, or CAD) and heart failure, according to the AHA.

Weight management can help

The good news is that losing weight may help manage and improve AFib. One study published in the Journal of the American College of Cardiology in 2015 found that losing weight may help your heart go back to a regular rhythm if you’ve already developed AFib. The study included 1,415 people with AFib, the majority of whom had a BMI of 27 or higher. Maintaining a weight loss of at least 10 percent (25 pounds if you weigh 250 pounds) over the course of five years was associated with a six times higher likelihood of having a regular heart rhythm.

It's yet another reason to stick with your weight loss efforts and support your overall health. Healthy eating habits that incorporate portion control and nutrient-rich foods, along with regular exercise, can go a long way toward helping you reach and maintain a healthy weight. You can also ask a HCP for help in finding a safe and effective weight loss plan that works for you.