Drinking too much coffee can give your heart more caffeine than it can tolerate, and a new study finds that consuming more than 400 milligrams of caffeine a day increases the risk of cardiovascular disease in even healthy people.
“Regular caffeine consumption can disrupt the parasympathetic nervous system, which can increase blood pressure and heart rate,” explained lead study author Nenshi Kagatala from Zydus Medical College and Hospital, Dahod, India.
Kagatala and his team measured the blood pressure and heart rate of 92 healthy adults, aged 18 to 45, who had normal blood pressure at the start of the study, as they completed a three-minute step test.
About 20% of participants consumed more than 400 mg of caffeine daily, the equivalent of about four cups of coffee, 10 cans of soda, or two energy drinks.
Chronic daily doses of 400 mg were found to increase heart rate and blood pressure over time, the study findings were presented Thursday at the American College of Cardiology conference in Delhi, India.
The U.S. Food and Drug Administration acknowledges that some people are more sensitive to caffeine than others and may metabolize it at different rates, but says that consuming 400 mg of caffeine per day is “generally not associated with dangerous adverse effects.”
According to the Mayo Clinic, up to 400 mg of caffeine is “likely safe for most healthy adults.”
Caffeine is a stimulant that promotes the production of the stress hormones norepinephrine and epinephrine, narrowing blood vessels, increasing heart rate and raising blood pressure.
But it also has been shown to have a range of benefits, including boosting mood and possibly lowering the risk of certain cancers.
Kagatala found in her study that urban women in business and managerial positions had the highest daily caffeine intake.
People who consumed more than 600 mg of caffeine per day had significantly increased heart rate and blood pressure after a five-minute break following the step test.
“Because caffeine affects the autonomic nervous system, regular caffeine consumption can put even healthy people at risk for hypertension and other cardiovascular diseases,” Kagatala said. “Increasing awareness of these risks is essential to improving heart health for everyone.”
Hypertension, another name for high blood pressure, is a condition that increases the risk of coronary artery disease, heart failure, chronic kidney disease, and dementia.
Experts recommend regular exercise and a nutritious diet to lower blood pressure. If losing weight, changing your diet, and exercising don’t help, medications may be prescribed.