Matt Jaeky was only 19 the first time his heart went into atrial fibrillation (AFib). He had just come home after working a long, hot day in his summer job cutting grass and changing water meters for the Indian Head Park, Illinois, public works department.
“My mom said, ‘You don’t look too good – you’re gray,’” says Jaeky, now 54. “And I said, ‘My arm is tingling and my heart is racing.’” His mom rushed him to their family doctor, who was astonished to hear Jaeky’s heart beating out of rhythm.
Inside Jaeky’s heart, the delicate web of electrical signals that coordinate the pumping of the upper and lower chambers was going haywire. “In the atria, which are the heart's upper chambers, there are many electrical impulses all running around at once,” says Rachel Lampert, MD, a Yale University electrophysiologist who studies the effects of AFib on athletes.
“During AFib, the atrium doesn't squeeze at all,” says Lampert, who isn’t Jaeky’s doctor. “It just sits there and quivers. And then the ventricles, the lower chambers, become irregular.” Sometimes the lower chambers beat faster; sometimes they beat more slowly.
AFib doesn’t always feel like it did for Jaeky (and it usually starts much later in life). Some people describe it as feeling like worms are crawling around in their chest. Others get palpitations, like their heart is jumping around. But as many as 30% of AFib patients feel nothing at all.
Since that first episode, Jaeky has often had bouts of AFib. He estimates that he’s gotten elective cardioversion – which restores the heart’s normal rhythm – nearly 40 times.
But there’s one preventive measure that he’s shied away from: exercise.
“My heart’s clicking at 140 beats per minute when I’m sitting on the couch, and someone wants me to get on a treadmill and get my heart rate up?” Jaeky asks. “I’m terrified of getting my heart rate too high and triggering something.”
Like Jaeky, an estimated 59 million people worldwide have AFib. In the U.S., AFib is the root cause of about 28,000 deaths each year. And it accounts for 1 in 7 strokes.
There are medications and procedures to treat AFib – and those are musts for many people.
But exercise is a critical part of living with AFib.
Plenty of research backs that up. For instance, a 2024 research review found that exercise-based cardiac rehab cuts down on AFib recurrence, lessens symptoms, and shortens the length of AFib episodes.
AFib experts put exercise to the test in a 2023 Australian study of 120 people with AFib. Half of the patients got a personalized workout routine that ramped up their physical activity until they got at least 210 minutes of exercise per week. They also did weekly supervised intervals, pounding out four minutes on a treadmill or exercise bike, then resting for two minutes, doing that cycle four times. That all adds up to a lot more than the typical recommendation to get 150 minutes per week of moderate activity. The Australian researchers didn't just want people to maintain their current fitness level; they wanted them to improve their heart and blood vessel fitness, hence the extra exercise and the intervals.
For comparison, the other 60 patients in the study learned about the benefits of exercise and got generic recommendations to do 150 minutes of moderate physical activity per week – but no structured, supervised plans tailor-made for them.
After 12 months, 40% of the people in the exercise group had achieved freedom from AFib – meaning they didn’t have any episodes during that period – compared to 20% of those in the control group. And for the people in the exercise group who still had AFib episodes, it was rarer, milder, and shorter than in the control group.
“It’s worth stating that this was freedom from AFib without drug therapy or invasive intervention,” says study author Adrian Elliott, PhD, an exercise physiologist at the University of Adelaide.
How Exercise Knocks Out AFib
Everyone already knows that exercise is good for the heart. It boosts the fitness of your heart and blood vessels, and that makes simple daily tasks like walking up stairs easier and less likely to stress your heart.
Beyond that, working out also does these things to help keep AFib in check: It improves your body’s blood sugar control, reduces sleep apnea, and balances your sympathetic nervous system, or fight-or-flight response, and the parasympathetic nervous system, which calms you down.
Lastly, there also seems to be an electrical advantage. Elliott’s team recently reported that in a study of 100 AFib patients, those with better heart and blood vessel fitness also had better electrical activity and healthier cardiac tissue in their heart’s left atrium (the upper left chamber).
Here’s why that matters: Exercise may alter the structures that move electrical currents across the heart, making AFib episodes less likely. Those adaptations, Elliott says, “are the changes most associated with AFib, because this is essentially the ‘fuel’ of the AFib.”
Stop Fear From Stopping You
The perception that too much exercise can trigger AFib stems in part by a very real fact: Elite athletes performing at the highest levels, particularly male athletes, are much more likely to get AFib. In fact, top-tier endurance athletes are between two and ten times more likely to develop AFib than people who don’t exercise at all, a recent research review shows.
But most of us aren’t elite athletes. And for us mere mortals, the benefits of regular exercise are far too good to miss.
To understand the risk, picture a U-shaped curve. That’s what the risk of developing AFib as it relates to exercise looks like, says Gregory Marcus, MD, a professor of atrial fibrillation research at the University of California, San Francisco.
“There’s a benefit in the middle of the curve, and it drops off as people start to get into really high numbers of time spent exercising or cardio,” Marcus says. “These are people who are cycling at peak intensity four or more hours a day, every day of the week – not a recreational marathoner.”
On the recreational side of fitness is Peter Capozzoli, a 75-year-old retired Department of Defense employee. He was 62 when he found out that he had AFib. While he doesn’t have physical symptoms of AFib, “I have never been in normal sinus rhythm since 2010,” he says.
After his diagnosis, Capozzoli cut down on his typical hourlong runs. But that didn’t stop him from competing in the Maryland Senior Olympics, where he won in 2020 in his age group for the 50-meter and the 100-meter sprint. Today, he lifts weights four or five days each week, and combines sprints and brisk walking almost daily. Capozzoli says his doctor gave him the green light to continue exercising once he got used to the beta-blocker medications he needed, and to cut back on very heavy weight training.
“Bottom line: AFib can't be cured with exercise and diet,” Capozzoli says, “but I believe it should reduce symptoms and possibly reduce AFib burden.”
Exactly How Much Exercise Does It Take?
Most people with AFib can start with easy workouts without needing to see their doctor, Marcus notes. The exceptions are if you physically don't feel up to it, or your doctor has already specifically told you to avoid physical activity.
"You should generally just go ahead and start," Marcus says. "Even people with heart failure and coronary disease tend to experience more benefits than risks by engaging in regular physical activity."
Researchers say the type of workout itself doesn’t matter, as long as you keep at it for at least 30 minutes, and you can do it seven days a week, like in the Australian study. A busy weekend of yard work and chores, or even a long run, won’t be as effective as daily moderate exercise.
“If you're sitting around all week not exercising, and then you run 10 miles on Saturday, you're going to be challenging your body in a way that it’s not used to,” Lampert says. “You're going to have more adrenaline, and that might actually make you more prone to have AFib.”
If you haven’t exercised in years, or even just a few weeks, take the time to gradually rebuild your fitness. Elliott suggests increasing the time you spend working up a sweat by between 10% and 20% each week. Then once you’re getting 150 minutes per week of exercise, you can add interval training or sprints for an extra boost for your heart and blood vessels.
“The total weekly exercise time should be approximately 210 minutes per week to achieve the benefits we are looking for,” Elliott says. That’s 3.5 hours per week, or 30 minutes every day.
That’s the plan for Jaeky. After learning about the ways exercise can stave off AFib, he reconsidered his long-held aversion to working out.
“I’m absolutely going to start exercising,” he says – something his doctor has been nudging him to do.
