Beyond the Morning Buzz: How Does Coffee Affect Your Heart?

Majalla - Harvard Heart

Java junkies may have perked up after hearing that drinking coffee may lower heart disease risk. But are there grounds to support this claim?

In recent years, researchers have observed that people who drink about three cups of coffee daily may be slightly less likely to develop heart disease or to die from it than people who avoid the aromatic brew. A review article in the Nov. 22, 2017, issue of The BMJ that included nearly 300 studies on the health effects of coffee came to a similar conclusion. However, as the authors point out, their findings can’t prove cause and effect. In the absence of long-term, randomized trials that assign people to drink coffee or not, it’s impossible to say whether the popular drink (or some other factor) led to the lower heart risk.

“If you like coffee, it’s fine to drink it. But please don’t go out of your way to increase your intake in hopes of helping your heart,” says Dr. Patrick O’Gara, a cardiologist at Harvard-affiliated Brigham and Women’s Hospital.


Coffee contains some 1,000 different bioactive chemicals. Among these are vitamins, minerals, and potent, plant-based anti-inflammatory compounds known as polyphenols. The combination of these substances (which are also plentiful in fruits and vegetables) may exert favorable effects on the heart and blood vessels. And with respect to coffee’s effects on other heart-related factors, the brew seems fairly benign.

Drinking coffee or other caffeinated beverages does increase your blood pressure, but only temporarily. Over the long term, consuming caffeine on a daily basis hasn’t been shown to elevate blood pressure. Still, the recently updated national guidelines on high blood pressure recommend limiting caffeine to less than 300 milligrams (mg) per day. While a home-brewed, 8-ounce cup of coffee may contain about 100 to 150 mg of caffeine, the amount in some to-go sizes at popular coffee shops is often much higher (see “Caffeine content in common drinks”).



Among the myriad chemicals found in coffee are oily substances called diterpenes, which appear to slightly raise harmful LDL cholesterol levels. That’s according to studies of people who drink unfiltered coffee, which includes coffee made using a French press, Scandinavian-style boiled coffee, and Turkish coffee.

To make pressed coffee, you mix boiling water and coarsely ground coffee beans in a small pitcher called a French press, let it steep for a few minutes, and then press a mesh plunger from the top of the pitcher to the bottom to strain the liquid and trap the coffee grounds.

However, most of the coffee drunk in this country is filtered. The commonly used paper or metal mesh filters trap diterpenes, keeping them out of your cup.

If you choose to drink unfiltered coffee, keep an eye on your cholesterol levels to make sure your LDL doesn’t rise over time. But any change is likely to be small.


People have a wide range of responses to coffee and caffeine, says Dr. O’Gara. Some people are very sensitive to caffeine and develop a pounding or irregular heartbeat after drinking a single cup of coffee. Others say coffee leaves them jittery, anxious, and unable to fall asleep at night. Coffee can also trigger heartburn — an uncomfortable burning sensation in the center of the chest that’s sometimes mistaken for a heart attack.

But many people who enjoy coffee’s rich flavor and mild stimulant effect don’t have those problems. For them, drinking a few cups of coffee a day is fine — even if they have heart disease, says Dr. O’Gara. “For the most part, heart attack survivors can drink coffee even during recovery, as caffeine doesn’t seem to strain the heart,” he says. Coffee also does not appear to worsen heart failure.

If you have atrial fibrillation (afib), a heart rhythm disorder marked by an irregular, fast heart rhythm, or palpitations — a noticeably strong, fast, or irregular heartbeat — pay close attention to whether caffeine makes a difference in your symptoms. If so, try cutting back. Can’t live without coffee? “Drink one cup of regular coffee and one cup of decaf, or two cups of ‘half-caf’ coffee. Most people can live with that,” says Dr. O’Gara. But if you rely on coffee to spend less time sleeping, that’s a bad idea. “Sleep deprivation can be very hard on your heart,” he cautions.

Finally, be mindful of coffee add-ins like cream, sugar, or sugary flavored syrups, which are popular in specialty coffee drinks (see “Anatomy of a coffee drink”). These add saturated fat and empty calories to your diet, boost your blood sugar, and promote weight gain.

A Grande Caffè Mocha from Starbucks contains about the equivalent amount of coffee as two cups brewed, but will cost you close to 400 calories, 35 grams of sugar, and 19 grams of fat. Drinking a couple of these treats each day may get you into the range where coffee’s potential benefits kick in, but the add-ins will do more harm than good in the long run.