This Amount of Caffeine Is Bad for Your Heart

Consuming over 400 mg of caffeine on most days of the week may increase the risk of cardiovascular disease in healthy individuals, a new study suggests.

A new study being presented at ACC Asia 2024 in Delhi, India, looked at how chronic caffeine consumption affects cardiovascular health.

Chronic caffeine consumption was defined as consuming any caffeinated drink — coffee, tea, and aerated beverages like Coke and Monster — five days per week for more than one year.

The study included 92 healthy individuals with normal blood pressure between 18 and 45 years old. They all had their blood and pulse measured before and after undergoing a three-minute step test, which measures aerobic fitness based on how quickly the heart rate recovers after exercise.

The authors also collected information on each participant’s sociodemographic data and daily caffeine intake.

They found that nearly one in five participants (19.6%) consumed more than 400 mg of caffeine daily, translating to about four cups of coffee, eight cups of black tea, 10 cans of soda, or two energy drinks.

The highest daily caffeine intakes were observed in participants who were female, employed in business and management roles, and living in urban areas.

Those who consumed the highest amounts, chronic caffeine consumption of more than 600 mg of caffeine per day, had significantly elevated heart rates and blood pressure after five minutes of rest following the step test.

“Due to its effect on the autonomic nervous system, regular caffeine consumption could put otherwise healthy individuals at risk of hypertension and other cardiovascular events. Increasing awareness of these risks is vital to improve heart health for all,” lead author Nency Kagathara, MBBS, Department of Internal Medicine, Zydus Medical College and Hospital, Dahod, India, said in a statement.

High blood pressure weakens the heart over time and is a leading risk factor for heart disease. However, risk factors like alcohol consumption, smoking, or family medical history can also contribute to increased blood pressure.

In the United States, about 85% of adults consume 135 mg of caffeine daily, which is equivalent to 12 ounces of coffee.

Most people can safely consume under 400 mg of caffeine a day, according to the Food and Drug Administration. However, some conditions and medications may make people more sensitive to caffeine’s effects.

Caffeine overconsumption may cause the following effects:

Drinking moderate amounts of coffee and tea can have health benefits, including for the heart. However, it is important to stay within the recommended limit.