The American Heart Association (AHA) has released a new scientific statement on caffeine and cardiovascular disease, published today in its journal Circulation. The statement, based on a comprehensive review of the latest research, concludes that for most adults, consuming up to 400 milligrams of caffeine per day—equivalent to about five 8-ounce cups of caffeinated coffee—is safe and may be linked to a lower risk of several cardiovascular conditions, including heart failure, heart disease, and stroke.
However, the statement warns that higher doses of caffeine, particularly those found in energy drinks and energy shots, can increase the risk of high blood pressure and irregular heart rhythms (arrhythmias). Energy drink shots may contain 40-69 mg of caffeine per fluid ounce, three to four times the caffeine concentration of regular coffee.
“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. “However, high doses of caffeine, such as those found in energy drinks including energy shots, may have harmful effects on the heart and should be avoided.”
The statement highlights that coffee contains bioactive compounds with antioxidant and anti-inflammatory properties, which may contribute to its health benefits. Adding sugar, flavored syrups, milk, or cream likely reduces these benefits. The research also notes that unfiltered coffee (e.g., espresso, French press) contains cafestol, which can raise LDL (“bad”) cholesterol, whereas paper-filtered or instant coffee does not.
Key findings from the statement include: drinking 1-3 cups of caffeinated coffee daily was not associated with an increased risk of atrial fibrillation, but higher caffeine doses from energy drinks have been linked to arrhythmias in young, healthy adults. Two to four cups per day was linked to lower risks of heart disease, heart failure, and stroke, while more than four cups may increase heart failure risk. For blood pressure, 1-3 cups was associated with a higher risk of hypertension in people with optimal blood pressure, but more than 3 cups showed a lower risk.
The statement emphasizes that individual responses to caffeine vary based on genetics, metabolism, age, and medications. “There is no ‘one-size-fits-all’ strategy for safe caffeine consumption,” Marcus noted. “What may be a reasonable amount for one person could cause unwanted effects in another.”
The AHA calls for more research on different caffeine sources, especially energy drinks, and their long-term cardiovascular effects. The statement does not provide specific intake recommendations but informs the development of future dietary guidelines.
