A recent study has found that drinking two or more cups of coffee a day may double the risk of dying from heart disease in people who have very high blood pressure. This condition, known as severe hypertension, means having a blood pressure reading of 160 over 100 mm Hg or higher.
The researchers studied over 18,000 adults in Japan, including about 6,570 men and 12,000 women, aged 40 to 79. They looked at how coffee and green tea habits affected health over time.
The study showed that people with severe high blood pressure who drank two or more cups of coffee each day had twice the risk of heart-related death compared to people with the same blood pressure who didn’t drink coffee.
However, the same risk was not seen in people who drank only one cup of coffee a day, or those who drank green tea regularly. Even though both drinks contain caffeine, only high coffee intake seemed to increase risk in people with severe hypertension.
The researchers believe that caffeine may have harmful effects when blood pressure is already very high.
While caffeine can offer some health benefits—such as improving alertness, mood, and possibly lowering the risk of some diseases—too much of it may raise blood pressure, cause anxiety or heart palpitations, and interfere with sleep. These effects can be especially dangerous for people with severe hypertension.
Green tea, on the other hand, may offer heart-protective benefits without the same risks. One reason could be the presence of polyphenols—natural compounds in plants that have antioxidant and anti-inflammatory effects. These compounds may help reduce damage to blood vessels and support heart health, even in people with high blood pressure.
Earlier studies have suggested that drinking one cup of coffee a day may help people who’ve had a heart attack live longer, and may even reduce the risk of heart problems in healthy individuals. But for those with very high blood pressure, it now seems that drinking too much coffee may do more harm than good.
So, what can people with high blood pressure do to protect their hearts?
First, it’s important to check your blood pressure regularly. This helps you and your doctor keep track of changes and adjust treatments if needed. If you’re taking medication for high blood pressure, be sure to follow your doctor’s instructions. Skipping pills or stopping suddenly can cause your blood pressure to rise quickly.
Eating a healthy diet also plays a big role. Try to include lots of fruits, vegetables, whole grains, lean proteins like fish or chicken, and healthy fats such as olive oil or nuts. At the same time, cut down on salt, sugar, and unhealthy fats, which can raise your blood pressure.
Staying active helps, too. Just 30 minutes of walking, biking, or other moderate exercise most days of the week can lower your blood pressure and keep your heart strong. Managing stress through relaxation techniques—like deep breathing, meditation, or yoga—can also make a difference.
If you smoke, quitting is one of the best things you can do for your heart. And if you drink alcohol, keep it in moderation—no more than one drink per day for women and two for men.
Overall, if you have severe high blood pressure, it may be wise to limit your coffee intake and talk to your doctor about the best ways to manage your condition. Green tea may be a safer alternative with added health benefits. As always, make decisions based on your personal health needs and work closely with your healthcare provider.
This study was conducted by Dr. Hiroyasu Iso and colleagues and published in the Journal of the American Heart Association. It adds to the growing body of research that helps people make informed choices about their diet, lifestyle, and heart health.
If you care about high blood pressure, please read studies that early time-restricted eating could help improve blood pressure, and natural coconut sugar could help reduce blood pressure and artery stiffness.
For more information about blood pressure, please see recent studies about How to eat your way to healthy blood pressure and results showing that Modified traditional Chinese cuisine can lower blood pressure.
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