Is Caffeine Good for Your Heart?

Caffeine is a daily companion for millions of people in the form of coffee, tea, energy drinks, and soda.

It’s easy to think of caffeine as harmless, especially since it’s socially accepted, widely available, and even associated with certain health benefits. Yet caffeine’s effects go far beyond keeping you awake. It acts on your nervous system, influences your cardiovascular function, and alters the way your heart responds to stress and exertion.

For those with or at risk for heart rhythm disorders like atrial fibrillation (Afib), it’s worth understanding how caffeine affects the heart’s electrical system.

Is that morning cup of coffee harmless – or a potential trigger?

Caffeine and the Heart’s Electrical System

Caffeine is a central nervous system stimulant with multiple physiological effects. After you consume it, caffeine blocks adenosine receptors, the chemical pathways in the brain and heart that normally promote relaxation and slow electrical activity. This blockage prompts the release of catecholamines (neurotransmitters and hormones like adrenaline), which temporarily raise your heart rate and blood pressure.

Caffeine also mobilizes free fatty acids from adipose tissue, which affects how your body uses energy. On top of that, it has mild diuretic properties, increasing urine output and potentially contributing to dehydration – something that can influence cardiac function and overall fluid balance.¹

While caffeine clearly has an effect on the cardiovascular system, research has not found strong evidence linking moderate caffeine consumption to a higher risk of arrhythmias, including atrial fibrillation. One study involving individuals with significant structural heart disease and arrhythmias found no increase in premature ventricular contractions (PVCs) following modest caffeine intake, even as catecholamine levels rose.²However, it’s worth noting that electrical activity changes are dose-dependent and differ between habitual consumers and those less accustomed to caffeine.

Caffeine Tolerance

Your body’s reaction to caffeine depends heavily on how accustomed you are to it. Habitual consumers often develop a degree of tolerance, meaning their cardiovascular system doesn’t respond as dramatically to caffeine’s stimulatory effects. In contrast, those who rarely consume caffeine may experience stronger effects, such as more noticeable increases in heart rate or palpitations, even at lower doses.

For most people, an average daily intake of 200 to 400 milligrams (about two to four cups of brewed coffee) is generally considered safe and unlikely to pose a significant risk of arrhythmia. Still, individual responses vary widely – “safe” is not the same for everyone. Variations in how an individual metabolizes caffeine, dehydration, and even stress levels can interact with caffeine’s stimulant effects. For some, that translates into palpitations or irregular heartbeats, even with lower amounts.

While habitual caffeine drinkers can often tolerate higher doses without issue, very high doses can provoke electrical disturbances sufficient to trigger palpitations or extra heartbeats, regardless of tolerance and especially in people with established arrhythmia issues.

Large quantities of caffeine can come from a strong cup of coffee, concentrated energy drinks, caffeine pills, or pre-workout supplements, and can cause uncomfortably noticeable heart rhythm changes.

In some cases, excess caffeine can cause:

• Palpitations or fluttering sensations
• A racing heartbeat (tachycardia)
• Extra or skipped beats
• Shortness of breath, dizziness, or lightheadedness

These effects can grip anyone with or without an existing heart condition in both habitual and non-habitual caffeine users, but people with existing arrhythmias are generally more vulnerable.

Research Perspective

Current research generally supports the idea that moderate caffeine use is safe for most people, even those with some forms of heart disease. The slight, temporary increases in heart rate and blood pressure seen after caffeine consumption rarely translate into dangerous arrhythmias in healthy individuals.

In fact, some studies suggest that regular coffee consumption is linked with a lower risk of certain heart issues, including arrhythmias. According to the American College of Cardiology (ACC), drinking a specific amount of caffeine can ward off strokes, heart failure, and Afib. Note: that does not mean someone who is not already a caffeine user should start drinking copious amounts of coffee.

One analysis tracked more than 380,000 adults without pre-existing heart disease over a ten-year period to see how different levels of coffee intake influenced the development of heart disease, stroke, and arrhythmias. The findings suggested that drinking two to three cups of coffee daily was linked to the most benefit, including a 10–15% lower risk of coronary heart disease, heart failure, or arrhythmias. Researchers also noticed that drinking more or less than that resulted in a slight decrease in the benefits, but the lowest stroke risk was seen among those consuming around one cup per day.³

A follow-up study focused on 34,000 participants who already had cardiovascular disease at the outset, and consuming two to three cups of coffee daily was associated with improved mortality. Researchers also noted that any modest level of coffee intake did not increase the risk of arrhythmias, including atrial fibrillation or atrial flutter.³

Researchers also examined whether the type of coffee mattered, comparing instant vs. ground and caffeinated vs. decaffeinated versions. The data showed that two to three cups of caffeinated coffee daily provided the strongest association with lower risk of arrhythmias, coronary artery blockages, stroke, or heart failure, regardless of whether the coffee was ground or instant. While decaffeinated coffee did offer some cardiovascular protection, it did not reduce the incidence of new arrhythmias. Overall, the findings suggest that caffeinated coffee is generally preferable for heart health, though individuals should avoid increasing intake if it causes discomfort, anxiety, or jitteriness.³

Can Caffeine Combined With Alcohol Affect Your Heart Rhythm?

Caffeine is a stimulant, while alcohol is a depressant. When consumed together, as in coffee cocktails or energy drinks with liquor, these substances send mixed signals to the nervous system. Caffeine may blunt the sedative effects of alcohol, causing people to feel more awake than they really are, which can lead to excessive alcohol intake and increased cardiac strain.

For individuals with or at risk of Afib, combining caffeine and alcohol could increase the chances of experiencing arrhythmias. Both substances interact with the autonomic nervous system, potentially disrupting the regulation of heart rate and rhythm. The overstimulation may lead to palpitations or skipped beats, especially in those who are sensitive to either substance on its own.

There’s also a delayed effect to consider. Caffeine often wears off before alcohol fully clears the system. This can leave the body in a vulnerable state, especially at night when the nervous system tries to return to a relaxed “rest and digest” phase. The shift may act as a trigger for arrhythmia if the heart has already been taxed by the earlier stimulant/depressant combo.

While occasional combinations may not cause issues for everyone, those with a history of atrial fibrillation or sensitivity to cardiac rhythm changes may want to steer clear of mixing the two.

Practical Tips for Heart-Safe Caffeine Use

If you’re trying to balance your love of caffeine with heart health concerns, these strategies may help:

1. Track your daily intake from all sources (coffee, tea, energy drinks, chocolate, medications) and explore other options for boosting your energy.
2. Counteract caffeine’s mild diuretic effect with extra fluids and stay hydrated throughout the day.
3. Avoid large doses late in the day to prevent interference with sleep, which can indirectly affect heart rhythm.
4. Pay attention to palpitations, rapid heartbeat, or unusual fatigue that occurs after caffeine use.

For most people, caffeine can be part of a healthy lifestyle if consumed in moderation, but for those with existing rhythm issues or sensitivity, small adjustments or avoidance may be beneficial.

Listen to Your Heart

Your heart’s rhythm powers every moment of your life – if you notice palpitations, fluttering, or unusual heart sensations after consuming caffeine, take it seriously.

Based on current interpretations of research, the low-level circulatory changes induced by moderate caffeine intake, such as a slight increase in heart rate and blood pressure, rarely translate into clinically significant arrhythmias. Patients with known arrhythmias should monitor their own reactions carefully and discuss personalized consumption limits with their healthcare practitioner.

Always consult your healthcare provider before making changes to your caffeine intake, particularly if you have a history of arrhythmia or heart disease.

This information is not a substitute for professional medical advice. Always consult your healthcare provider if you have a history of heart rhythm issues or symptoms that concern you. In case of a medical emergency, call 911.

Dr. Tordini is a part of Florida Medical Clinic, Orlando Health.

1. American Heart Association. (2023, September 12). Caffeine and Heart Disease. Www.heart.org. https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/nutrition-basics/caffeine-and-heart-disease.
2. Planning Committee for a Workshop on Potential Health Hazards Associated with Consumption of Caffeine in Food and Dietary Supplements, Food and Nutrition Board, Board on Health Sciences Policy, & Institute of Medicine. (2014, April 23). Caffeine Effects on the Cardiovascular System. Nih.gov; National Academies Press (US). https://www.ncbi.nlm.nih.gov/books/NBK202224/
3. American College of Cardiology. (2022, March 25). Studies Finds Drinking Two to Three Cups of Coffee a Day May Benefit the Heart. American College of Cardiology. https://www.acc.org/Latest-in-Cardiology/Articles/2022/03/25/17/36/Coffee-a-Day-May-Benefit-the-Heart-acc-2022.