Study finds too much caffeine raises risk of heart damage, stroke

Caffeine consumed regularly in high quantities — including coffee, tea, cola beverages and energy drinks, among others — may increase the risk of heart disease, according to a study from India that’s being presented at the American College of Cardiology Asia 2024 scientific meeting in Delhi, India.

The researchers, from Zydus Medical College and Hospital in Dahod, India, found that drinking more than 400 milligrams of caffeine a day most days of the week could increase the risk of heart problems in otherwise healthy people. That’s roughly four cups of coffee, 10 cans of soda or two energy drinks, the researchers said.

“Regular caffeine consumption could disturb the parasympathetic system, leading to elevated blood pressure and heart rates,” said lead author Nency Kagathara, from the Department of Internal Medicine, in a news release . “Our study sought to determine the effects of chronic caffeine consumption on heart health, specifically the recovery of heart rate and blood pressure.”

The researchers defined chronic caffeine consumption as drinking any caffeinated drinks five days a week for more than a year. The researchers said they focused on “tea, coffee and aerated beverages such as Coke, Pepsi, Redbull, Sting and Monster.” They used a randomized group of 92 healthy people ages 18-45 with normal blood pressure. All of them had their blood pressure and pulse taken and did a three minute step test, then their blood pressure and heart rates were measured at one minute and five minutes after that test. Researchers also looked at sociodemographic data and daily caffeine intake.

About 20% of participants consumed more than 400 milligrams of caffeine a day. Drinking that much caffeine almost daily “was shown to significantly impact the autonomic nervous system, raising the heart rate and blood pressure over time.”

Women working in business and management roles who live in urban communities had the highest intake, per the researchers.

People who consumed the most caffeine — 600 milligrams daily — had significantly elevated blood pressure and heart rates even when they rested for five minutes after the step test.

The researchers noted that high blood pressure raises the risk of coronary artery disease, chronic kidney disease, heart failure and dementia.

They wrote that “hypertension weakens your heart over time and is a leading risk factor for heart disease. In addition to caffeine intake, there are several factors that could contribute to high blood pressure, such as alcohol consumption, smoking, age, family medical history and salt consumption. Increasing physical activity, following a nutritious diet and other lifestyle changes could help lower blood pressure and reduce the risk of heart disease.”