When you’re in atrial fibrillation, certain habits, substances, and reactions can make an episode worse or raise your risk of serious complications like stroke. The most important things to avoid fall into a few categories: drinking alcohol, taking certain over-the-counter medications, ignoring warning signs that need emergency care, and skipping or stopping prescribed blood thinners.
Don’t Drink Alcohol
Alcohol is one of the most reliable triggers for Afib episodes. It damages the connections between heart cells, triggers inflammation and oxidative stress, and disrupts the electrical channels that keep your heart rhythm steady. It also ramps up your sympathetic nervous system (the “fight or flight” side) and reduces your heart rate variability, both of which make irregular rhythms more likely.
Even moderate, “socially acceptable” amounts of alcohol cause structural changes in the left atrium over time, including enlargement and scarring. These changes make future episodes more likely regardless of whether you’re actively drinking. The acute risk is real too: a large study of over 36,000 people found that occasional spikes in drinking, the pattern sometimes called “holiday heart syndrome,” were linked to a significant jump in emergency department visits for new-onset Afib. If you’re already in Afib or prone to episodes, alcohol is the single most avoidable trigger.
Don’t Take Certain OTC Medications
Some common over-the-counter products can spike your heart rate or blood pressure and worsen Afib. The biggest offenders are decongestants containing pseudoephedrine or phenylephrine, which are found in many cold and sinus medications. These drugs stimulate the same “fight or flight” pathways that destabilize heart rhythm.
Energy drinks and weight-loss supplements are another category to avoid entirely. Many contain stimulant compounds beyond caffeine. Synephrine, a common ingredient, has long-lasting effects on the nervous system that raise heart rate and systolic blood pressure. Yohimbine, found in some sexual health and weight-loss supplements, increases blood pressure and heart rate and can cause palpitations and anxiety. Guarana delivers roughly 40 mg of caffeine per gram on top of whatever caffeine is already listed on the label. If you’re in Afib, read labels carefully on any supplement or cold medicine, and choose products specifically labeled as safe for people with heart conditions.
Don’t Ignore Stroke Warning Signs
Afib increases stroke risk because blood can pool in the upper chambers of the heart and form clots. When those clots travel to the brain, they cause strokes. Your individual risk depends on factors like age, high blood pressure, diabetes, and prior stroke history. For people with multiple risk factors, the annual stroke rate can climb above 13 per 100 patient-years. Even with just one or two risk factors, the rate sits between 1 and 3 per 100 patient-years.
The symptoms that demand an immediate 911 call during an Afib episode include: face drooping, confusion, slurred speech, dizziness or balance problems, numbness or weakness on one side of the body, a sudden severe headache, or vision changes. These are signs of a stroke in progress, and every minute of delay costs brain tissue. Chest pain or pressure that comes on suddenly, happens at rest, or lasts longer than usual also warrants emergency care, as it can signal that your heart isn’t getting enough blood.
Don’t Stop Taking Blood Thinners
If you’ve been prescribed anticoagulants, skipping doses or stopping them without medical guidance is one of the most dangerous things you can do in Afib. These medications exist specifically to prevent the blood clots that cause strokes. Missing even a short window of protection can leave you vulnerable, especially if you have additional risk factors. If you’re experiencing side effects or concerned about bleeding risk, that’s a conversation to have with your prescribing clinician rather than a reason to quietly stop the medication.
Don’t Let Low Electrolytes Slide
Potassium and magnesium play direct roles in maintaining a stable heart rhythm. When potassium drops below 3.5 mmol/L, Afib risk increases. Low magnesium has been linked to Afib as well, particularly in people without underlying structural heart disease. You can become depleted through heavy sweating, diarrhea, vomiting, diuretic medications (water pills), or simply not eating enough mineral-rich foods.
If you’re in Afib and also dealing with dehydration, stomach illness, or are on diuretics, pay extra attention to replenishing electrolytes. Potassium-rich foods include bananas, potatoes, spinach, and beans. Magnesium is found in nuts, seeds, whole grains, and dark leafy greens. If you take a diuretic, ask whether you need a potassium-sparing version or a supplement.
Don’t Neglect Sleep Apnea
Obstructive sleep apnea and Afib are deeply intertwined, and ignoring one makes the other harder to control. People with untreated sleep apnea who undergo procedures to correct Afib have roughly 2.8 times the risk of Afib recurrence compared to those without sleep apnea. The connection isn’t just statistical: episodes of blocked breathing directly trigger Afib in the moments immediately after each apnea event, meaning your heart rhythm is being disrupted dozens of times per night.
The tricky part is that most people with sleep apnea in the Afib population don’t report classic symptoms like excessive daytime sleepiness. Many cases go undiagnosed unless screening is done deliberately. If you have Afib and haven’t been evaluated for sleep apnea, particularly if you snore, wake up feeling unrefreshed, or have a large neck circumference, getting tested could be one of the most impactful things you do for rhythm control.
Don’t Try Vagal Maneuvers for Afib
You may have heard that bearing down (the Valsalva maneuver) or other vagal techniques can “reset” a fast heartbeat. These maneuvers are a legitimate first-line treatment for a different arrhythmia called supraventricular tachycardia, or SVT, and they work by briefly increasing the calming branch of the nervous system. But Afib is not SVT. Vagal maneuvers are not a standard treatment for atrial fibrillation, and in rare cases they can actually provoke Afib or other dangerous rhythms. The electrical chaos of Afib originates in a different part of the heart than the circuits these maneuvers target.
Don’t Assume Caffeine Is the Enemy
For years, people with Afib were told to cut out coffee. Recent evidence tells a different story. A randomized clinical trial (the DECAF trial) assigned coffee drinkers who had undergone successful cardioversion to either continue drinking caffeinated coffee or abstain from all caffeine. The coffee group actually had a 39% lower risk of Afib recurrence compared to the abstinence group, with no increase in adverse events. The coffee drinkers averaged about one cup per day.
This doesn’t mean you should start drinking coffee if you don’t already, and high doses of any stimulant can be a problem. But if you’re a moderate coffee drinker with Afib, cutting out your daily cup may not help and could remove a small protective benefit. Energy drinks are a different matter entirely because of their additional stimulant ingredients.
Don’t Push Through Intense Exercise
Physical activity is generally beneficial for heart health, but high-intensity or prolonged endurance exercise during an active Afib episode is a different situation. When your heart is already beating irregularly, pushing your cardiovascular system hard can worsen symptoms like dizziness, breathlessness, and fatigue. It can also drive your heart rate dangerously high since Afib already impairs the heart’s ability to regulate how fast it beats. If you feel an episode starting during a workout, stop, sit down, and focus on slow breathing. Moderate exercise between episodes, once cleared by your care team, remains one of the best long-term strategies for reducing Afib burden.