Stiffness of the arteries was similar in moderate and heavy coffee drinkers, but coffee has many other effects on the body.

Coffee lovers, rejoice! A new study found you can drink up to 25 cups of coffee a day without increasing the stiffness of your arteries — a risk factor for heart attack and stroke.

But before you start brewing 1.5 gallons of medium roast to get you through your workday, keep in mind that arterial stiffness is just one factor that affects health.

To help you decide how much coffee is “too much” for you, here’s a breakdown of the new study, other research on the health effects of coffee, and some expert tips.

Coffee doesn’t affect arterial stiffness

In the new study published in BMJ Heart, researchers asked more than 8,000 people about their coffee consumption habits. They also measured participants’ arterial stiffness in two different ways.

Researchers divided people into three groups based on how much coffee they drank: less than one cup a day, one to three cups a day, and more than three cups a day.

They excluded people who drank more than 25 cups of coffee a day.

Arterial stiffness was similar across all three groups, even for people who reported drinking up to 25 cups a day.

Researchers also took into account other factors, such as a person’s blood pressure, resting heart rate, alcohol consumption, and diet. These didn’t affect the results.

The study was presented Monday at the British Cardiovascular Society conference.

However, the relationship between coffee and health is more complicated than just arterial stiffness.

“Coffee and caffeine have a wide range of effects on the body outside of the cardiovascular system. When consumed in high amounts, these effects can be harmful,” said Dr. Parveen Garg, assistant professor of clinical medicine at Keck School of Medicine of USC.

But he also points to research showing the benefits of coffee on health.

“There has been a lot of recent literature to suggest that higher caffeine/coffee consumption may actually be associated with a reduced risk of cardiovascular disease,” Garg said.

Other studies have also found that more than four cups of coffee a day may protect against certain types of cancerTrusted Source, dying from chronic liver disease Trusted Source, and a lower risk of death overall Trusted Source.

Finding the coffee sweet spot

Many of these studies, though, compare coffee drinkers to people who don’t drink coffee.

Elina Hyppönen, PhD, director of the Australian Centre for Precision Health at the University of South Australia Cancer Research Institute, says non-coffee drinkers may not be the best comparison group.

“People tend to avoid drinking coffee if it makes them feel unwell,” she said. “Or if they are feeling unwell, this may make them reduce their coffee intake.”

In one studyTrusted Source, Hyppönen instead compared heavy coffee drinkers to people who drank moderately — one to two cups of coffee a day.

When done this way, she found that people who drank more than six cups of coffee a day — and also non-coffee drinkers — had a higher risk for cardiovascular disease, compared to moderate coffee drinkers.

When Hyppönen reanalyzed the data from earlier studies in the same way — including those showing a benefit from high coffeeintake — she found that moderate intake was linked to the lowest risk of cardiovascular disease.

However, people aren’t just coffee drinkers or non-coffee drinkers. They have other habits that can affect their health, including things like diet, exercise, and sleep. 

Sometimes these overlap with coffee consumption.

Dr. Satjit Bhusri, a cardiologist at Lenox Hill Hospital in New York City, points out that in the new study, moderate and heavy coffee drinkers were more likely to smoke and drink alcohol — both risk factors for cardiovascular disease.

How much coffee is too much?

The optimum amount of coffee varies from person to person.

“Individuals may respond differently to caffeine due to genetic differences and may have unique experiences related to tolerance and withdrawal,” said Whitney Linsenmeyer, PhD, RD, LD, a spokesperson for the Academy of Nutrition and Dietetics and nutrition instructor at Saint Louis University.

It also depends on how quickly you consume the caffeine. If you drink coffee quickly, you may outpace your body’s signals that it’s time to stop.

“The good thing with coffee is that it gives signs to indicate when we have reached our limit,” Hyppönen said. “These can include unpleasant sensations such as feeling jittery, irritable, and restless, but side effects can also include fast or irregular heartbeat, headaches, and gastrointestinal disturbances.”

Many experts, though, recommend drinking coffee in moderation.

“This new study suggests that high levels of coffee may not be harmful as it relates to artery hardening,” Bhusri said, “but I do not believe 25 cups of coffee is considered moderation. At these levels there is an increased risk [of health problems].”

According to the 2015–2020 Dietary Guidelines for AmericansTrusted Source, moderate coffee consumption is three to five cupsa day, providing up to 400 milligrams of caffeine per day.

Linsenmeyer notes people also need to be mindful of consuming other drinks and even foods with added caffeine, including caffeinated waters, juices, energy drinks, chocolates, candies, and even potato chips.

And remember that what you put in your coffee can also affect your health.

“Keep it simple,” Linsenmeyer said. “Get your caffeine from black coffee or tea. Skip the sugar — good coffee really doesn’t need it.”