NEW YORK, Aug 15: Regularly drinking more than four cups of coffee a day may elevate the risk of severe heart disease, according to a recent study. Researchers have found that consuming over 400 milligrams of caffeine daily is associated with an increase in heart rate and blood pressure over time, potentially leading to serious cardiovascular issues.

The study, conducted by Dr. Nency Kagathara and her team at Zydus Medical College and Hospital in India, examined 92 individuals with healthy hearts. Participants' heart rates and blood pressures were measured before and after a three-minute cardio exercise, and data on their caffeine consumption and demographics were recorded.

The findings revealed that nearly 20 percent of participants consumed more than 400 milligrams of caffeine daily, which is equivalent to about two Celsius energy drinks, nine cups of black tea, or 11 Coca-Colas. For context, a Venti Starbucks cold brew contains approximately 310 milligrams of caffeine.

Dr. Kagathara noted, “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.” She explained that the increase in heart rate and blood pressure may cause wear and tear on blood vessels and the heart, potentially leading to heart attacks, strokes, or heart failure.

The CDC and NHS recommend limiting caffeine intake to no more than 400 milligrams per day. Pregnant women and breastfeeding mothers are advised to consume less. Those exceeding this limit were found to have significantly higher blood pressure and heart rate, both generally and following exercise.

The researchers acknowledged that their results might also be influenced by other factors such as participants' activity levels, age, or dietary habits. However, Dr. Kagathara emphasized the importance of raising awareness about these risks to improve heart health.

The study also noted that individuals most likely to consume excessive caffeine were women living in urban areas and working in business environments. These findings were presented at the American College of Cardiology Asia's 2024 conference and are pending publication in a scientific journal.

While short-term high blood pressure is not immediately harmful, chronic hypertension can strain the heart and blood vessels, leading to severe health problems including heart attack, stroke, kidney issues, vascular dementia, and vision problems. Similarly, a persistently high heart rate can cause comparable complications.

Caffeine, the most widely used psychoactive substance globally, temporarily blocks receptors in the brain that control sleep, memory, attention, and learning. This increases oxygen flow to the brain, speeds up the heart rate, and enhances concentration. However, excessive caffeine intake can cause adverse effects such as headaches, nausea, anxiety, jitters, increased body temperature, and a flushed face. Extremely high doses, over 5,000 milligrams, can be fatal.

Previous research has suggested that moderate caffeine consumption may not be harmful and could even benefit certain health aspects, such as gut health and longevity. Some studies have indicated that moderate coffee consumption might be associated with longer life for office workers.