DALLAS – The American Heart Association (AHA) has issued a new scientific statement clarifying the cardiovascular effects of caffeine, concluding that for most adults, up to 400 milligrams per day—equivalent to about five 8-ounce cups of brewed coffee—is safe and may even reduce the risk of several heart conditions. However, the statement warns that higher doses, particularly from energy drinks and energy shots, can increase the risk of high blood pressure and irregular heart rhythms.
Published today in the AHA’s flagship journal Circulation, the statement titled “Caffeine and Cardiovascular Disease” reviews the latest research on caffeine consumption and heart health. “Caffeine consumed in coffee is a key part of daily life for millions of people, and in our review of the most recent research, for most adults, intake of up to 400 mg of caffeine/day, the equivalent of up to 5 cups of caffeinated coffee per day without added sugars or fillers, is safe and does not increase cardiovascular risk,” said Dr. Gregory M. Marcus, chair of the statement writing group and professor of medicine at the University of California, San Francisco.
The statement notes that coffee is the primary source of caffeine for most adults, but other products like tea, chocolate, soda, and energy drinks also contribute. The writing group emphasized that not all caffeine sources are equal. Energy drinks and shots can contain 40-69 mg of caffeine per fluid ounce—three to four times more than regular coffee—and are often consumed in high doses quickly, which can lead to adverse effects.
Key findings from the statement include that consuming 2-4 cups of caffeinated coffee daily was linked to a lower risk of heart disease, heart failure, and stroke. However, drinking more than 4 cups a day may increase heart failure risk. The statement also highlights that adding sugar, flavored syrups, milk, or cream likely reduces coffee’s potential health benefits.
Regarding specific conditions, the research suggests that 1-3 cups of coffee per day was not associated with an increased risk of atrial fibrillation, but higher doses from energy drinks have been linked to arrhythmias in healthy young adults. For blood pressure, moderate coffee consumption had mixed effects, but high caffeine doses from energy drinks significantly raised blood pressure, especially in those with hypertension.
The statement also addresses cholesterol: unfiltered coffee (e.g., French press, espresso) contains cafestol, which can raise LDL (“bad”) cholesterol, while paper-filtered or instant coffee does not. For type 2 diabetes, regular black coffee consumption was linked to a lower risk, though this may be due to other compounds in coffee.
Dr. Marcus stressed individual variability: “People can respond very differently to caffeine based on various factors, such as age, medications, underlying health conditions, genetics and how quickly their bodies metabolize it.” The AHA calls for more randomized controlled trials to better understand caffeine’s effects, especially from energy drinks, and to inform future dietary guidance.
The statement reinforces that while moderate coffee consumption can be part of a heart-healthy diet, high-caffeine energy products should be avoided due to potential cardiovascular harm. The full statement is available online at the AHA’s website.
