• New research indicates that one hour of moderate exercise per week can help prevent atrial fibrillation (AFib).
• The study utilized robust data from thousands of individuals using FitBit fitness trackers to report exercise behavior.
• While a minimum amount of exercise lowered AFib risk in study participants, those who exercised more reaped even greater benefits.

A single hour of exercise per week can cut your risk of developing atrial fibrillation, according to new research.

The findings build on prior evidence suggesting that exercise, even at minimum recommended levels, is protective against atrial fibrillation (AFib), the most common form of heart arrhythmia.

The protective benefits of exercise expand with more physical activity. Participants who exceeded recommended exercise saw even greater reduced risk compared to those who did the least.

These latest findings are compelling due to the strength of the data. The study included individuals with one year of accelerometry data (from health and fitness trackers like Fitbit). Data from fitness wearables is preferable in research because it is viewed as more objective in reporting exercise behavior.

Most existing studies on the subject have typically relied on self-reported behavior, which is notoriously unreliable. They have also been too short (about one week) to be of much scientific value.

The authors say the new study is the largest of its kind.

“This study makes use of high quality objective physical activity data that reassuringly aligns with the previous kind of less high quality data to support that greater amounts of physical activity are associated with a reduced risk of developing atrial fibrillation,” Sean P. Heffron, MD, director of cardiovascular fitness and nutrition at the NYU Langone and senior author of the research, told Healthline.

Heffron and his team’s work is currently being reviewed for publication. The study will be presented at the upcoming American Heart Association Scientific Sessions on November 16 in Chicago.

Every hour of exercise lowered AFib risk by 11%

Heffron’s team utilized health and accelerometry data from the All of Us Research Program led by the National Institute of Health.

The program includes health, genetic, lifestyle, and demographic data for a cohort of individuals intended to reflect the diversity of the United States, including groups historically underrepresented in medical research.

More than 6,000 individuals were included in the study. The group was predominantly white (83%) and female (70%). Cohort members also tended to be college-educated.

To be included, participants had to have at least one year of accelerometry data and health records.

Researchers wanted to investigate how exercise levels, based on WHO Guidelines, affected AFib outcomes over a five-year follow-up period. The WHO recommends adults get a minimum of 150 minutes of physical activity per week.

Like prior research, exercise was inversely associated with AFib risk, but exercise levels also made a big difference.

One key takeaway: Each hour of physical activity per week reduced the risk of AFib by 11%. Those hours are cumulative, too, so five hours of exercise would be the equivalent of a 55% reduction in risk.

Rod Passman, MD, a professor of medicine and director of the Center for Arrhythmia Research at Northwestern University, who wasn’t affiliated with the research, told Healthline, “This is an interesting study and supports current guidelines that lifestyle choices, including moderate levels of exercise, are an integral part of preventing AF.”

The protective benefit was also apparent when researchers grouped the participants by their average activity level. Compared to a sedentary individual (less than 30 minutes of exercise per week), exercise level was incrementally associated with reduced AFib risk:

• 30–150 minutes per week: 38% reduction
• 151–300 minutes per week: 60% reduction
• 300+ minutes per week: 65% reduction

“The more you exercise, the better. That’s not going to be a surprise. And that relationship is true for atrial fibrillation as well,” Evan L. Brittain, MD, MsC, an associate professor of cardiovascular medicine at Vanderbilt University Medical Center, who was not involved with the study, told Healthline.

Does too much exercise cause AFib?

Exercise is one of the most important parts of cardiovascular disease prevention, including atrial fibrillation. But is too much a bad thing?

Some studies have suggested that exercise may be an “emerging cause” for young, otherwise healthy individuals. However, only high-level and endurance athletes are likely to be at risk, and not the average American.

“There are some sort of provocative data showing that the benefits of exercise may reverse themselves once you get to an extreme amount of exertion. But, even if you are an extreme athlete, the overall benefits undoubtedly outweigh whatever sort of modest risk may emerge,” said Brittain.

Heffron, who works with endurance and other high level athletes in his practice, is even more blunt: “No one needs to worry about their exceeding the amount of activity to the point where they’re going to put themselves at risk for AFib.”

Both Heffron and Brittain strongly recommend that individuals try to get more physical activity into their day-to-day life.

“Never underestimate the impact of any amount of physical activity: five minutes here or there, it all adds up. You put together five minutes a few times a day, and over the course of a week, you’re going to reach the level that is going to help reduce your risk, not only of atrial fibrillation but of other cardiovascular diseases as well,” said Heffron.

Takeaway

Exercise is an important component of cardiovascular disease prevention, including atrial fibrillation (AFib). Research has indicated that exercise reduces the risk of AFib, but much of it has relied on low quality data.

New research based on thousands of individuals personal Fitbit data gives a clearer picture of the impact of exercise on AFib risk. The study suggests that every hour of exercise per week results in an 11% reduction in risk.

Some prior studies have indicated that extreme amounts of exercise may be a risk factor in developing AFib. However, doctors warn that the health risks of a sedentary lifestyle far outweigh any risks of excessive exercise.

AFib is the most common form of heart arrhythmia. It occurs when the heart’s two upper chambers (atria) beat irregularly. The condition can lead to a greater risk of heart attack, stroke, heart failure, and sudden cardiac arrest.