Countless studies have analyzed the health implications of drinking coffee, with no consensus on whether it’s “good” or “bad” for our hearts. Part of the problem is that most research on coffee’s effects has been observational – reliant on self-reported data that can’t be analyzed separately from a patient’s overall health, daily lifestyle, and diet.
But an innovative study presented at the American Heart Association’s (AHA) 2021 Scientific Sessions is changing our perceptions of coffee and heart health.
The Coffee and Real-time Atrial and Ventricular Ectopy (CRAVE) clinical trial returned the first set of data that illustrates a quantifiable link between heart rhythm, duration of sleep, and coffee consumption.
Researchers from the University of California, San Francisco, asked 100 generally healthy CRAVE participants (median age 38) to alternate days on which they consumed one to three cups of coffee. Their biophysical responses to the caffeine were captured through continuously worn electrocardiogram (ECG) monitors, activity tracker watches, and continuous blood glucose monitors.
CRAVE showed that on coffee-drinking days, trial participants:
- Experienced 54% more premature ventricular contractions (PVCs), or heart palpitations
- Got 36 fewer minutes of sleep
- Walked about 1,000 more steps
Each additional cup of coffee consumed beyond the three-cup limit was associated with a 3% increase in PVCs, 587 more steps per day, and 18 fewer minutes of sleep per night. Patients whose bodies metabolized caffeine slowly were more likely to lose sleep. Faster caffeine metabolizers were more likely to experience heart palpitations.
So, what do the results of this study mean for you? Like all good things in life, enjoying coffee should be an exercise in moderation – and each of us should tailor our caffeine consumption to what makes the most sense for our heart health.
Skipped heartbeats after coffee are probably safe
Whereas the CRAVE data showed an increase of heart palpitations on coffee days, it’s not necessarily a cause for alarm. Everyone experiences occasional heart palpitations, which can feel like your heart skipping a beat or a heavy thump. They rarely point to a serious problem. Participants in the CRAVE study did not have an increased risk of dangerous heart rhythms.
However, that doesn’t mean caffeine consumption is safe for everyone. When we look at the study results, it’s important to consider two key points:
- Participants generally drank three or fewer cups of coffee a day; this is a relatively modest amount.
- These individuals were young and generally healthy, with no heart rhythm conditions that might be affected by caffeine consumption.
If you have an existing heart condition or if you experience new or more frequent PVCs, talk with your provider about whether drinking coffee is right for you. A few and occasional extra beats can be normal, but racing heart beats, especially for several minutes to hours, can be a more concerning issue.
Call your doctor anytime you are concerned about your heart health. If you experience fainting, lightheadedness, or racing heartbeats for several minutes or more, call right away – these symptoms could indicate a serious heart rhythm disorder.
Related reading: The bitter truth: 25 cups of coffee might not be good for you
Meet Dr. Khera
Amit Khera, M.D., is a physician, researcher, and teacher at UT Southwestern, where he is also Director of the Preventive Cardiology Program. Beyond his clinical work, he pursues his passion for preventing cardiac disease by conducting extensive research in the subject.
The coffee tradeoff: Less sleep, more movement
CRAVE data suggest that drinking coffee correlates with getting less sleep and more physical activity. If you are generally healthy and normally sleep well, losing a little sleep but moving more might not put your heart health at risk. And moving more is associated with reduced risk of cardiovascular conditions such as obesity and diabetes, as well as several cancers.
I drink a cup of coffee every morning before I go for a run, and it helps give me a boost! For some patients, the tradeoff is worth it.
However, if you already have trouble sleeping, drinking coffee is not going to help your health. Over time, getting too little sleep has been linked to the risk of developing high blood pressure, heart disease, stroke, obesity, diabetes, and depression. Adults should try to get seven to nine hours sleep each night.
Heart health care you can wear
Wearables are opening a whole new way of thinking about research. New sensors and technology allow us to better understand what’s happening in real life – not just in a lab situation – allowing us to assess individualized triggers for abnormal heart rhythms such as atrial fibrillation.
In another study presented at this fall’s AHA event, patients selected the trigger they thought caused their A-fib, such as caffeine, alcohol, reduced sleep, exercise, or specific diets. After they were exposed to their self-selected trigger, a smartphone-based ECG device monitored their heart rate. Researchers found that what many people thought triggered their A-fib in fact did not. This personalized data can help us design care plans that more fully consider a patient’s overall health.
UT Southwestern cardiologists are using wearable technology in many ways. For example, our cardiac rehabilitation is testing ways to monitor patients’ home-based exercise. Patients frequently bring their mobile EKG recordings from their smart devices for their cardiologist to review. And there are helpful data coming from step counters, sleep trackers, and heart rate, blood pressure, and oxygen sensors.
As we work toward more personalized, real-time clinical applications for wearable data, we’re developing advanced processes to capture, protect, and analyze specific information more efficiently. I look forward to seeing how wearable technology will assist us in guiding patients toward improved heart health.
And it’s satisfying to know that, for many patients, enjoying a cup of Joe likely isn’t a major vice after all.
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