Many people enjoy coffee every day, and it’s often seen as a comforting and energizing part of daily life.
But a new study suggests that drinking too much coffee could be dangerous for people with very high blood pressure.
According to researchers, having two or more cups of coffee each day may double the risk of dying from heart disease in people whose blood pressure is 160/100 mm Hg or higher.
On the other hand, drinking just one cup of coffee a day or drinking green tea did not show any increased risk, even though both drinks contain caffeine.
This study adds to what we already know—and don’t fully understand—about coffee and heart health. In the past, studies have had mixed results. Some have suggested that drinking coffee in moderate amounts may help reduce the risk of heart attacks or strokes.
Others have shown that regular coffee drinkers may benefit from better mental alertness, lower risk of depression, and even protection from some long-term diseases.
However, drinking too much coffee can lead to problems, especially for people with heart conditions. These problems can include higher blood pressure, feeling anxious, irregular heartbeats, and trouble sleeping.
In this study, scientists divided blood pressure levels into five categories. “Optimal and normal” was anything below 130/85 mm Hg.
Then came “high normal,” “grade 1 hypertension,” and finally, “grade 2” and “grade 3 hypertension.” Grade 2 starts at 160/100 mm Hg, and grade 3 is even higher. Grades 2 and 3 are considered severe high blood pressure.
The study followed more than 18,000 adults in Japan—about 6,570 men and 12,000 women—aged between 40 and 79 years. Researchers kept track of them for almost 19 years. During that time, 842 people died from heart-related causes.
What they found was eye-opening. People with severe high blood pressure who drank two or more cups of coffee each day were twice as likely to die from heart disease compared to people with similar blood pressure who didn’t drink coffee.
In contrast, those who had just one cup of coffee per day had no added risk, no matter what their blood pressure was.
Green tea also showed no link to a higher risk of death, regardless of blood pressure levels. That’s an important finding, especially since green tea contains caffeine too.
Scientists believe this may be because green tea also has special plant compounds called polyphenols. These are known to have antioxidant and anti-inflammatory effects, which may help protect the heart.
So, what does this all mean? If you have very high blood pressure, it might be wise to limit your coffee intake. While moderate coffee consumption can still be safe for many people, too much might do more harm than good—especially for those already at risk.
And if you’re looking for a healthier alternative, green tea could be a good choice. As always, it’s best to talk with your doctor about what’s right for your specific health needs.
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