A recent study presented at the American College of Cardiology Conference in New Delhi has raised concerns about the impact of high caffeine consumption on heart health. The research, published on August 17, indicates that consuming more than 400 milligrams (mg) of caffeine daily is associated with an elevated risk of cardiovascular problems.
In the U.S., approximately 85% of individuals consume at least one caffeinated beverage daily. The Food and Drug Administration (FDA) advises that a daily intake of up to 400 mg of caffeine is generally safe for most healthy adults. However, exceeding this limit may pose risks.
Impact of High Caffeine Intake
The study involved 92 healthy participants aged 18 to 45, all with normal blood pressure. Researchers assessed their caffeine intake from coffee, tea, and carbonated drinks and measured their blood pressure and heart rate after a three-minute step test designed to evaluate cardiovascular response.
Nearly 20% of participants consumed at least 400 mg of caffeine daily—equivalent to four cups of coffee, two energy drinks, or ten cans of soda. This level of caffeine intake was linked to significant increases in heart rate and blood pressure over time. Those consuming over 600 mg of caffeine daily showed even more pronounced effects, including elevated heart rates and blood pressure during rest periods following the step test.
Dr. Nency Kagathara, the study’s lead author, emphasized that regular high caffeine consumption could stress the autonomic nervous system, potentially leading to hypertension and other cardiovascular issues.
Caffeine’s Effects on the Cardiovascular System
Caffeine affects the cardiovascular system in several ways. It acts as a vasoconstrictor, narrowing blood vessels and raising blood pressure. “This is akin to the difference between water flowing through a hose versus a straw,” explained Amber Core, RD, a registered dietitian at The Ohio State University Wexner Medical Center.
As a stimulant, caffeine also triggers the body’s fight-or-flight response, which increases heart rate and blood pressure. While these effects are usually temporary, they can be more noticeable in individuals who do not consume caffeine regularly.
Research on caffeine’s overall impact is mixed. Some studies suggest moderate coffee consumption may reduce the risk of cardiovascular disease and other health benefits, such as a lower risk of type 2 diabetes and dementia. Conversely, excessive consumption—particularly for those with severe hypertension—could increase the risk of cardiovascular disease.
In addition to cardiovascular concerns, high caffeine intake can lead to symptoms like rapid heartbeat, jitters, and insomnia. Dr. Aeshita Dwivedi, a cardiologist at Northwell Health Lenox Hill Hospital, noted that excessive caffeine can also exacerbate anxiety.
Choosing the Right Caffeinated Drinks
Not all caffeinated beverages are equal. Energy drinks often contain high levels of caffeine, added sugars, and other ingredients like nitric oxide, which can negatively affect heart health. “Added sugars can lead to weight gain and diabetes, while nitric oxide may not be advisable for those with preexisting heart conditions,” Core said.
Even when opting for healthier caffeinated drinks, moderation is crucial. Symptoms such as insomnia, restlessness, or rapid heartbeat could indicate excessive caffeine consumption. Dr. Jason Hopper advises reducing caffeine intake if these symptoms occur and tailoring consumption to individual tolerance levels.
In summary, while moderate caffeine intake is generally considered safe, consistently exceeding 400 mg per day could pose significant risks to cardiovascular health.
