Drinking high amounts of caffeine 5 days a week may increase heart disease risk

• There have been many studies examining the potential positive and negative effects of caffeine on a person’s health.
• Much previous research has focused on how caffeine might impact heart health.
• A new study says that people who chronically drink high amounts of caffeine may increase their risk of cardiovascular disease, even if they are otherwise in good health.

Over the years, there have been numerous studies examining the potential effect — both positive and negative — of caffeine on a person’s health.

Much of this research has focused on the possible impact of caffeine — a stimulant found in beverages like coffee , tea, and energy drinks and foods like chocolate — on heart health .

One of the latest of these studies, recently presented at ACC Asia 2024 in India, reports that people who chronically drink high amounts of caffeine at least five days per week may increase their risk of cardiovascular disease, even if they are otherwise in good health.

What is a healthy intake of caffeine?

For this study, researchers recruited a random group of 92 healthy participants between the ages of 18 and 45. All study participants had their blood pressure and pulse measured and then participated in a three-minute step test. Their blood pressure and pulse were once again measured one minute and five minutes following the test.

Scientists also gathered information on the participants’ normal daily caffeine intake and their sociodemographic information.

“Regular caffeine consumption could disturb the parasympathetic system , leading to elevated blood pressure and heart rates,” Nency Kagathara, MBBS, a researcher in the Department of Internal Medicine at Zydus Medical College and Hospital in India and lead author of this study says in a press release . “Our study sought to determine the effects of chronic caffeine consumption on heart health, specifically the recovery of heart rate and blood pressure.”

For this study, researchers defined chronic caffeine consumption as drinking any caffeinated beverages — coffee, tea, soda, and energy drinks — five days during the week for more than one year.

At the study’s conclusion, the research team discovered that 19.6% of the study participants ingested more than 400 milligrams (mg) of caffeine each day, which is equal to about four cups of coffee, two energy drinks, or 10 cans of soda.

According to the U.S. FDA, 400 mg of caffeine per day is not normally associated with negative health issues for healthy adults. However, the FDA does warn that individuals react to and metabolize caffeine differently, and some people are more sensitive to caffeine than others.

High caffeine levels linked to elevated heart rate, blood pressure

Scientists found that chronic intake of 400 mg of caffeine daily showed a significant impact on the autonomic nervous system , leading to increased heart rate and blood pressure over time.

For participants who chronically consumed 600 mg of caffeine a day, which is higher than the recommended daily limit, scientists reported significantly elevated heart rate and blood pressure after five minutes of rest following the three-minute step test. This indicates that habitually high caffeine intake might hinder the recovery of heart rate and blood pressure after regular daily activity.

“Due to its effect on the autonomic nervous system, regular caffeine consumption could put otherwise healthy individuals at risk of hypertension and other cardiovascular events,” said Kagathara. “Increasing awareness of these risks is vital to improve heart health for all.”

Past studies show that ingesting more than 400 mg of caffeine or more a day may lead to health concerns, including anxiety and insomnia .

Unsurprising findings

Medical News Today spoke with Monique Richard, MS, RDN, LDN, a registered dietitian nutritionist and owner of Nutrition-In-Sight, about this study who commented that the findings were not surprising.

“Caffeine tolerance varies per individual as do effects and consequences; however, we understand the stimulating potential as well as are aware of the frequent population-wide use, which, for some, can be excessive. Chronic, excessive caffeine — above the recommended 400 mg a day — can elevate heart rate, (and) blood pressure, but depending on the form can come with additional drawbacks such as excessive sugar, calories, sodium, additives, and artificial ingredients.”
— Monique Richard, MS, RDN, LDN

MNT also spoke to Yu-Ming Ni, MD , a board certified cardiologist and lipidologist at MemorialCare Heart and Vascular Institute at Orange Coast Medical Center in Fountain Valley, CA, who expressed dissatisfaction with there being a large number of studies focused on coffee and caffeine, many times with conflicting findings.

“(With) coffee … there’s just so many unknown variables. We had not that long ago a study that showed that four cups of coffee a day or more was associated with longer survival. I feel like we keep on dragging on coffee. It’s either great, terrible or somewhere in between — it’s probably somewhere in between,” he said.

Caffeine in energy drinks

Richard also touched on other sources of caffeine, besides coffee.

“In practice, we have become aware of the increased intake of energy drinks, energy shots, and other beverages with excessive caffeine by adolescents who may be more susceptible to the dangerous consequences of excessive caffeine,” Richard said.

She also pointed out the side effects of consuming too much caffeine.

“Some of the side effects [of too much caffeine] can include dizziness, heart palpitations, jitteriness, anxiety, sleep interruptions, dehydration, diarrhea, nausea or decreased appetite, agitation, and difficulty maintaining focus among others,” Richard explained.

Meanwhile, instead of focusing on coffee for caffeine-related studies, Ni said he would like to see more studies on energy drinks and their impact on cardiovascular health.

“You have these energy drinks with like 300 milligrams of caffeine in one drink, which is insane,” he said.

Tips for cutting down on caffeine

Ni said it can sometimes be challenging for people who wish to cut back on their daily caffeine intake, as some people enjoy the taste of coffee.

“If it’s about just caffeine in general, I think part of the question is has caffeine become sort of a crutch for you to be able to go through your day?” he continued. “And if so, maybe try to just drink water during that time instead and just see what happens. I would not be surprised if you feel pretty much the same when you do that after about a week or so, once the caffeine gets out of your system, and then you don’t really need the caffeine.”

“People just assume they need the coffee to stay awake, but it becomes a sort of ritual to have coffee in the morning, and you may not actually need that at the end of the day once you’ve gotten it out of your system for a set period of time, and so it’s something worth experimenting with.”
— Yu-Ming Ni, MD

To decrease daily caffeine consumption, Richard suggested:

• start to slowly decrease daily intake while monitoring withdrawal symptoms such as headaches, irritation, a decrease in energy, and brain fog
• be sure to stay hydrated throughout the day with water or unsweetened beverages
• fill up on foods that naturally contain a lot of water (salads and vegetables like cucumbers, peppers, celery, and tomatoes, fruit like watermelon, citrus, grapes, and melons)
• recruit your friends and social network to support your goals or “decaf” together

“Take time to pause and make decisions today for tomorrow’s self — ingesting a caffeine and sugar-loaded beverage at lightning speed ‘in order to function,’ ‘get to the next level,’ or ‘make it through something’ is not conducive to long-term health,” Richard said. “Enjoy some chocolate, coffee, or tea but in an environment shared with others, nature, or your favorite book!”