Coffee has been part of human life for more than 600 years. Today, it is one of the most popular drinks in the world. Millions of people start their mornings with a cup of coffee, while others rely on it throughout the day for energy, focus, or comfort.
Some people prefer strong espresso, while others enjoy milder coffee drinks with milk or sugar. Coffee habits are influenced not only by taste but also by genetics. Scientists have found that genes affecting caffeine metabolism and the brain’s reward system partly determine how much coffee people enjoy drinking.
At the same time, coffee has long been debated in the world of health research. Some people worry that caffeine may increase blood pressure and raise the risk of heart disease. Others believe moderate coffee drinking may actually provide health benefits.
Now researchers say the relationship between coffee and blood pressure is more complicated than many people realize.
Blood pressure measures the force of blood pushing against artery walls as the heart pumps blood through the body. It is recorded using two numbers.
The higher number, called systolic blood pressure, measures pressure when the heart contracts and pushes blood out into the body. The lower number, called diastolic blood pressure, measures pressure when the heart relaxes between beats.
Healthy blood pressure is generally considered lower than 120/80 millimeters of mercury, also written as mm Hg. Blood pressure is considered high when readings consistently reach 140/90 or higher.
High blood pressure, also known as hypertension, is one of the biggest risk factors for heart attacks, strokes, kidney disease, and heart failure. One dangerous aspect of hypertension is that it usually causes no symptoms. Many people do not realize they have it until serious health problems appear.
Researchers estimate that around 31% of adults live with hypertension, and about half do not know they have it. Even among people taking blood pressure medication, many still do not have their condition fully controlled.
Scientists have known for years that caffeine can temporarily increase blood pressure. Caffeine acts as a stimulant that affects the heart, blood vessels, and nervous system.
When people drink coffee, caffeine can stimulate the adrenal glands to release adrenaline. This hormone increases heart rate and causes blood vessels to narrow, which may raise blood pressure.
Caffeine can also affect heart rhythm in some people, especially those sensitive to stimulants.
Blood caffeine levels usually reach their highest point between 30 minutes and two hours after drinking coffee. The body then slowly breaks caffeine down over several hours.
How quickly caffeine leaves the body depends on several factors. Genetics play a major role because some people naturally break down caffeine faster than others. Regular coffee drinkers also tend to process caffeine more efficiently than people who rarely consume it.
Research studies have shown that caffeine from coffee, cola, energy drinks, and chocolate can increase systolic blood pressure by around 3 to 15 points and diastolic blood pressure by about 4 to 13 points shortly after consumption.
However, scientists emphasize that short-term blood pressure increases do not necessarily mean coffee causes long-term hypertension.
In fact, several large studies suggest moderate coffee drinking is not strongly linked to developing high blood pressure over time.
One large scientific review analyzed 13 studies involving more than 315,000 people. During the follow-up period, more than 64,000 participants developed hypertension. Researchers found no clear evidence that coffee drinking increased the overall risk of developing high blood pressure.
The findings remained similar even after researchers considered differences such as gender, smoking habits, caffeine content, and length of follow-up.
Coffee also contains many other natural compounds besides caffeine. Scientists have identified hundreds of phytochemicals in coffee that may influence health.
Some of these compounds may actually help support healthy blood vessels and circulation. For example, quinic acid may improve blood vessel function and help the arteries handle pressure changes more effectively.
Melanoidins, another group of compounds formed during coffee roasting, may influence enzymes involved in blood pressure control.
Still, scientists say people with severe hypertension should be more cautious.
One long-term Japanese study followed more than 18,000 adults for nearly 19 years. Researchers found that people with very high blood pressure who drank two or more cups of coffee daily had roughly double the risk of dying from cardiovascular disease compared to non-coffee drinkers.
Interestingly, researchers did not see the same increased risk in people with normal blood pressure or mild hypertension.
This suggests coffee may affect people differently depending on their underlying health.
Experts say moderation is usually the key. Most healthy adults can likely continue drinking moderate amounts of coffee without major concern. Researchers generally suggest limiting intake to around four cups or fewer per day.
People with very high blood pressure, heart disease, arrhythmias, or other medical conditions may need to be more careful and discuss caffeine intake with their doctor.
Researchers also recommend avoiding caffeine shortly before blood pressure measurements because it may temporarily raise readings. Limiting caffeine later in the day may also improve sleep quality, which itself is important for healthy blood pressure.
The findings highlight how complicated nutrition research can be. Coffee contains many biologically active compounds that may both increase and reduce certain health risks at the same time.
The study findings are important because they show that moderate coffee intake may not significantly increase long-term hypertension risk for most people, despite caffeine’s short-term effects on blood pressure.
One major strength of the research is the inclusion of several very large population studies involving hundreds of thousands of participants. However, scientists still cannot fully explain why coffee appears safe for many people while potentially increasing risks in those with severe hypertension.
Individual genetics, caffeine sensitivity, and overall lifestyle may also influence results. More research is needed to better understand how coffee affects different groups of people over long periods of time.
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.
Source: The Conversation.
