What is Atrial Fibrillation?
Before I explain what atrial fibrillation is, it’s important to understand that normal electrical signals in the heart are timed so that the chambers beat in a coordinated rhythmic fashion (called normal sinus rhythm).
Blood from the top chambers (atria) is transferred down to your lower chambers (ventricles) and then pumped out to your body to meet oxygen and nutrient needs.
Atrial fibrillation is an extremely common condition and occurs when there is a “short-circuit” or disruption in the heart’s normal electrical conduction system, causing the atria (upper chambers) to beat in a rapid and irregular manner.
With a-fib, the atria beat as fast as 300 to 600 beats per minute. The atrioventricular node, which normally transfers the beats propagated in the atria down to the ventricles, serves as a buffer and fortunately does not conduct all these impulses in the ventricles.
The problem with atrial fibrillation is that the beats are irregular, altering the normal flow of blood through the heart’s chambers (from top down), causing incomplete filling of the ventricles. This, in turn, leads to less oxygen and nutrient-carrying blood pumped out to meet your body’s needs.
What are the signs and symptoms of atrial fibrillation?
Some people may have no overt symptoms, particularly if their atrial fibrillation is transient and each episode is short-lived.
Symptoms can range from palpitations (the feeling like your heart is fluttering in your chest), shortness of breath, chest pain, dizziness or fainting spells, weakness, or confusion. If you think about it, these symptoms make sense.
With atrial fibrillation, your heart muscle is not pumping out enough blood (due to inadequate filling of the ventricles), and without adequate oxygen getting to your brain, lungs, muscles, and other target organs, it’s only logical that you should feel lousy.
Stroke is also a possible consequence of atrial fibrillation. During atrial fibrillation, it is possible that blood can pool inside the heart, giving rise to a blood clot (thrombus) which, once it breaks off and exits the heart, floats around your circulatory system as a clog waiting to happen.
If it ends up in the brain, then you have a good old-fashioned stroke. This is precisely the reason why blood-thinning medications like warfarin and aspirin are so important for the treatment of atrial fibrillation.
Short video on atrial fibrillation and stroke risk
If you learn better from online videos, I found this short 3D animated clip on atrial fibrillation and its role in stroke.
What causes atrial fibrillation?
In some cases, the cause of atrial fibrillation is unknown. But in most instances, it occurs in tandem with other health conditions such as hypertension (high blood pressure), previous heart attack, valvular defects, congestive heart failure, or associated comorbidities like obesity.
In my experience working in cardiac rehab, it was also quite common to see patients with atrial fibrillation after open-heart surgery.
What are the treatments for atrial fibrillation?
You should understand that atrial fibrillation is not the end of the world. Your cardiac specialist will need to run some tests (such as an electrocardiogram or ECG) on you to ascertain how severe (or not severe) your condition is.
In many cases, it can be treated with anti-arrhythmic medication and blood thinners (see stroke risk above). Other approaches entail using cardioversion to “jolt” the heart back into normal rhythm, or catheter ablation to isolate and zap the specific region of the heart that is the source of the atrial fibrillation.
Exercise guidelines for atrial fibrillation
I am often asked for “right-wrong” or “black-and-white” guidelines for safe exercise with atrial fibrillation, but the short answer is always “it depends” on the individual circumstances.
A-fib often presents in concert with other underlying health conditions, so the exercise prescription cannot be a one size fits all approach.
To follow some random exercise program off the internet could leave you face down and unconscious on the pavement while taking your afternoon walk!
Having said that, the good news is that you CAN exercise safely with atrial fibrillation. Have a detailed discussion with your cardiologist and medical management team and find out if there are any specific considerations that would preclude you from doing any certain types of activities.
If you were previously active, then you should let them know what your previous regimen was and what you’d like to achieve now that you have atrial fibrillation. Because the condition can reduce how much blood is ultimately reaching your exercising muscles, you will likely need to start off at a low level and then gradually increase your intensity and duration as tolerated.
A heart rate monitor “may” help you, but the inherent problem is that the numbers might jump around a bit while your heart’s in atrial fibrillation. The most prudent advice is to consult a clinical exercise physiologist with experience in cardiac conditions.
Aerobic exercise guidelines for atrial fibrillation
You can perform aerobic exercise if it is deemed safe for your condition by your cardiologist. Aerobic exercise entails activities that incorporate the large muscles of your body and are continuous and rhythmic in nature (i.e., walking, bike riding, swimming).
You’ll want to customise the frequency, intensity, time (duration), and type of exercise to suit your individual condition and personal preferences.
Exercise frequency for atrial fibrillation
You can perform aerobic exercise anywhere from three to seven (3 – 7) days per week depending on your level of conditioning and exercise tolerance. If you’re already physically active, you may be able to tolerate more days per week, but if you’re an exercise newbie, then it’s probably better to start off with fewer days per week and work up from there as you adapt.
Exercise intensity for atrial fibrillation
Under normal circumstances (without a-fib), you can use percentages of max heart rate as a gauge of exercise intensity. But with a-fib, it’s not so straight forward given the variability of the ventricular heart rate. Commonly prescribed medications such as digoxin, calcium-channel blockers, diltiazem, or beta-blockers alter your heart rate response and therefore may render useless heart rate calculations.
Even so, it’s still not a bad idea to keep tabs on your exercise heart rate so you know what your individual response is under the effects of your medication regime.
If you have a hard time finding your pulse, consider getting yourself a heart rate monitor or a Fitbit (which also tracks your non-exercise movement habits).
I also recommend using what’s known as Borg’s 6 – 20 rating of perceived exertion (RPE) scale. In brief, RPE is a way to use your subjective opinion of how hard exercise is so you can tailor your efforts accordingly. In cardiac rehab, we recommend beginning with an RPE of “light to moderate” (11 – 12 on the RPE scale). If this feels manageable, then you can graduate to “somewhat hard to hard” (13-14).
Another alternative is what’s known as the “talk test.” If you can have a conversation with an exercise buddy, then the intensity should be approximately “moderate.” If you’re huffing and puffing a bit more but can still maintain the conversation, then this would be “somewhat hard.” Anything higher than that to where you genuinely cannot maintain the conversation is likely too hard.
Exercise duration for atrial fibrillation
If you’re new to exercise or very deconditioned after a difficult hospital stay, I would recommend starting off with short, incremental bouts of exercise. Begin with 5-10 minute intervals of low to moderate intensity activity. Perform multiple intervals throughout the day in order to accumulate 30+ minutes per day. Progress to longer intervals but slowly reduce the number of times per day you do them. Perform longer bouts until you’ve made it to 45 minutes of continuous activity (as tolerated).
Weight training with atrial fibrillation
I recommend you speak to your doctor before participating in resistance training exercise to ensure there are no medical reasons (aside from a-fib) that would preclude you from lifting weights. Generally lighter weights are well-tolerated in people with atrial fibrillation, but higher intensities might pose a risk in those with underlying high blood pressure, known coronary artery disease (blockages in arteries), ventricular arrhythmias, or congestive heart failure. If you can perform lifting exercises under the watchful eye of a clinical exercise physiologist who can monitor your heart rate and blood pressure responses, then you can experiment to find the right weight, reps, and sets appropriate for you.
Medications and their effects on exercise
There are a few medications that are frequently prescribed for people with atrial fibrillation. The main goals are to control or maintain a safe cardiac rhythm and minimise the risk of clot formation (which can lead to stroke). Common medications include:
Channel blocking and anti-arrhythmic medications act on your calcium, sodium, or potassium channels and serve to keep your rhythm under control. They slow down your heart rate and reduce the strength of the muscle cells’ contractions. Examples include Diltiazem and Verapamil (among others).
Sodium channel blockers slow down your heart’s ability to conduct electricity. Examples of these medications include Quinidine, Propafenone, and Flecainide.
Potassium channel blockers slow down the electrical signals that contribute to atrial fibrillation and include common meds such as Sotalol and Amiodarone.
Beta-blocking meds can also be prescribed and these act by slowing down your heart rate by blocking the effects of epinephrine. The end result is a lower heart rate and blood pressure.
Blood thinners are valuable for atrial fibrillation in that they minimise your risk of clot formation and, consequently, a stroke or heart attack. Common examples of this include Warfarin, aspirin, Apixaban, or Rivaroxaban.
Interaction of medications, exercise, and atrial fibrillation
If you are prescribed medications for your atrial fibrillation, then you may need to alter your exercise prescription. First, your exercise heart rate will not climb to the same levels it did before you were taking the medications. So if you use a “heart rate training range” then the calculations are probably not going to be accurate. In this case, use the Borg Rating of Perceived Exertion (RPE) scale. Try to find an intensity that is consistent with an effort level of around 12 to 13 (moderate to somewhat hard).
Second, you may find that your blood pressure will not climb as high as usual and this can leave you feeling a bit more fatigued than usual. If so, remember to give yourself time to adjust to the medications and recognise you may need to readjust your workloads. You can slowly work back up to the higher workloads as you readjust to the meds.
Third, your blood thinners, by very nature, increase your risk of bleeding, both internally and externally. You may notice easy bruising if you bump your arm or leg against something. It’s generally advisable to avoid contact sports since this can increase your risk of internal bleeding.
Work with your doctor to find the medications that get the job done but do not completely bog you out with strong side effects. This might take a little bit of trial and error, but explain your interest in exercising and ask which ones will be most complementary to getting active again.
Take home message
Atrial fibrillation can be a scary condition, but your best weapon is a thorough evaluation and diagnosis and education on how best to manage it. I have worked with countless patients with atrial fibrillation and most go on to live completely normal and uneventful lives (no news is good news, right?). In nearly all cases, they were able to exercise quite safely provided their condition was medically managed and well-controlled.
Please share your thoughts, experiences, or questions in the comments section below.