Coffee is one of the most popular drinks in the world. For many people, it is part of their morning routine and a source of comfort, energy, and focus. Some people enjoy a cup while working, studying, or relaxing with friends.
Over the years, many studies have explored how coffee affects human health. Some research has suggested that moderate coffee drinking may help lower the risk of some diseases and may even support brain health and mood.
However, a new study from Japan shows that drinking too much coffee could be risky for people who already have very high blood pressure.
The research was published in the Journal of the American Heart Association. Scientists wanted to better understand how coffee and green tea affect people with different blood pressure levels. High blood pressure, also called hypertension, is a major health problem around the world.
It increases the risk of heart attacks, strokes, heart failure, and other serious conditions. Many people do not even know they have high blood pressure because it often causes no clear symptoms in the early stages. That is why doctors sometimes call it a “silent killer.”
In this study, researchers followed more than 18,000 adults in Japan for nearly 19 years. The participants included about 6,570 men and around 12,000 women between the ages of 40 and 79.
During the long study period, the scientists recorded information about the participants’ health, lifestyle, coffee drinking habits, and green tea intake. They also tracked deaths linked to heart disease.
To better understand the results, the researchers divided blood pressure into several groups. The healthiest group had blood pressure below 130/85 mm Hg. Other groups included people with slightly higher readings and those with more serious hypertension.
The most severe groups included people with blood pressure levels of 160/100 mm Hg or higher. These levels are considered dangerous because they place extra strain on the heart and blood vessels.
During the study, 842 participants died from heart-related diseases. When researchers looked closely at the data, they found something important.
People with severe high blood pressure who drank two or more cups of coffee every day had about twice the risk of dying from heart disease compared with people who did not drink coffee. This increased risk appeared only in people with very high blood pressure.
Interestingly, drinking just one cup of coffee per day did not seem to increase the risk of death, even in people with high blood pressure. The study also found that green tea did not raise the risk of heart-related death at any blood pressure level.
This finding surprised some scientists because both coffee and green tea contain caffeine. Caffeine is known to temporarily raise blood pressure and increase alertness. However, green tea also contains natural plant substances called polyphenols. These compounds may help protect the body because they have antioxidant and anti-inflammatory effects.
Antioxidants help protect cells from damage, while anti-inflammatory effects may reduce harmful stress in the body. Researchers believe these substances could help explain why green tea did not show the same harmful effect as heavy coffee drinking.
The study adds to the ongoing debate about coffee and health. In recent years, coffee has often received positive attention from scientists. Some studies have linked moderate coffee drinking with lower risks of stroke, type 2 diabetes, depression, and even some brain diseases. Coffee also helps many people feel more awake and focused.
Still, coffee is not completely harmless for everyone. Drinking large amounts may lead to anxiety, nervousness, fast or irregular heartbeats, poor sleep, and temporary increases in blood pressure. People who already have heart problems or severe hypertension may be more sensitive to these effects.
The researchers say their findings suggest that people with very high blood pressure should be careful about drinking too much coffee. Having one cup each day may still be safe for many people, but drinking two or more cups daily could increase health risks for those with severe hypertension.
The study does not prove that coffee directly causes heart disease deaths. It only shows a strong connection between heavy coffee drinking and higher risk in people with severe high blood pressure. Other lifestyle factors may also play a role. Even so, the results are important because high blood pressure affects millions of people worldwide.
Doctors often recommend healthy habits such as eating less salt, exercising regularly, maintaining a healthy weight, avoiding smoking, reducing stress, and limiting alcohol to help control blood pressure. This new research suggests that limiting coffee may also be worth considering for some people with severe hypertension.
For people looking for another warm drink, green tea may be a healthier option. Besides caffeine, it contains compounds that may support heart health. However, health experts still recommend talking with a doctor or healthcare professional about the best choices for your own body and medical condition.
As scientists continue to study coffee and heart health, one message is becoming clearer: moderation matters. Coffee may be safe and even helpful for many people when consumed in reasonable amounts, but too much could become dangerous for people already facing serious blood pressure problems.
If you care about blood pressure, please read studies about blood pressure drug that may increase risk of sudden cardiac arrest, and these teas could help reduce high blood pressure.
For more health information, please see recent studies about nutrient that could strongly lower high blood pressure, and results showing this novel antioxidant may help reverse blood vessels aging by 20 years.
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