Up to five cups of coffee per day OK for heart health. Energy shots, not so much
American Heart Association
However, higher amounts of caffeine, such as levels found in energy drinks including energy shots, may increase the risk of high blood pressure and/or irregular heart rhythm or arrhythmia.
More research is needed to better understand caffeine’s impact on the body, how different sources of caffeine impact heart health and how its impact may vary among different people, according to the scientific statement.
Previous studies have found that caffeine is the world’s most popular stimulant and psychoactive substance, and coffee is the most common way people consume caffeine. The latest research supports the conclusion that for most adults, consuming up to 400 mg of caffeine/day (or up to 5, 8-ounce cups of caffeinated coffee per day) is safe and appears to be linked to a lower risk of cardiovascular disease for some individuals.
However, higher doses of caffeine, such as levels found in energy drinks including energy shots, may cause cardiovascular harm, according to a new American Heart Association scientific statement, “Caffeine and Cardiovascular Disease,” published today in the American Heart Association’s flagship peer-reviewed scientific journal Circulation.
“Caffeine consumed in coffee is a key part of daily life for millions of people, and in our review of the most recent research, for most adults, intake of up to 400 mg of caffeine/day, the equivalent of up to 5 cups of caffeinated coffee per day without added sugars or fillers, is safe and does not increase cardiovascular risk,” said Chair of the scientific statement volunteer writing group Gregory M. Marcus, M.D., M.A.S., FAHA, a professor of medicine at the University of California, San Francisco School of Medicine and the associate chief of Cardiology for Research at the University of California, San Francisco Health.
“However, high doses of caffeine, such as those found in
energy drinks including energy shots, may have harmful effects on the heart and
should be avoided.”
The statement authors note that studying the effects of
caffeine on the cardiovascular system is challenging. Coffee is the main source
of caffeine in most research studies, and the observed cardiovascular effects
may be due to other compounds in coffee. For example, experimental studies
suggest that the bioactive compounds in coffee may have antioxidant and
anti-inflammatory properties, which may help explain some health benefits. It’s
also difficult to separate the effects of caffeine from other ingredients
usually added to coffee, such as milk, cream, flavored syrups and/or sugar. In
addition, most studies on caffeine are observational, meaning they cannot prove
cause and effect.
Although coffee is the main source of caffeine for most
adults, tea, chocolate, soda and energy drinks, as well as over-the-counter and
prescription medications, also contribute to overall caffeine intake. More
research is needed about other products with caffeine in order to understand
caffeine content and caffeine’s impact on cardiovascular health.
The new scientific statement details the most recent
research primarily on caffeinated coffee and the potential impact of caffeine
in coffee on high blood pressure, cholesterol, Type 2 diabetes, coronary heart disease, stroke, heart failure, atrial fibrillation, other arrhythmias and other
cardiovascular conditions.
Caffeine and cardiovascular health: key things to know
- Based
on the results of the latest research studies reviewed, consuming up to
400 mg of caffeine per day, or no more than 3 to 5, 8-ounce cups of
regular black caffeinated coffee per day (without sugars, sweeteners,
flavors or added fillers), is considered safe for most adults. A regular
brewed, non-specialty, caffeinated coffee typically contains 9.4-20.6 mg
of caffeine per fluid ounce.
- Consuming
caffeinated coffee without added sugars, flavors or cream was linked to a
lower risk of Type 2 diabetes, heart disease, stroke, heart failure and
some irregular heart rhythms.
- Randomized
trials, the most rigorous and reliable type of study design, have shown
that caffeine consumption in coffee is associated with a lower risk of
atrial fibrillation but also a higher risk of premature ventricular
contractions.
- Adding
sugar, flavored syrups, milk and/or cream to coffee likely reduces its
potential health benefits, and more research is needed to understand the
impact of these additives.
- Higher
caffeine intake, such as levels found in energy drinks including energy
shots, was associated with cardiovascular harm, such as increased risk of
high blood pressure and irregular heart rhythm. Energy drink shots may
contain 40-69 mg of caffeine per fluid ounce, 3-4 times more caffeine than
regular caffeinated coffee.
How does caffeine affect the body?
Caffeine consumed in coffee is metabolized by the liver and
generally reaches peak concentration for most people within an hour. However,
how quickly individuals process caffeine depends on their genetics, metabolism,
age and past caffeine use. When more caffeinated coffee is consumed regularly,
some people may develop a tolerance to higher levels of caffeine. Other people
may feel stronger effects from the same amount of caffeine. Short-term effects
of caffeine may include temporary increases in blood pressure, heart rate,
blood sugar and alertness. Some people may experience heart palpitations and/or
sleep disruption.
Specific health impacts of caffeine:
- Effects
on blood pressure: Studies have found that caffeinated coffee
consumption may affect blood pressure differently depending on how much is
consumed. In people with optimal blood pressure, drinking 1–3 cups a day
was associated with an increased risk of developing high blood pressure, while drinking more than 3 cups
per day was associated with a lower risk. High doses of caffeine (such as
those from energy drinks or energy shots) can significantly increase blood
pressure, especially in people who already have high blood pressure.
- Effects
on Type 2 diabetes: Research suggests that caffeinated coffee may
reduce insulin sensitivity in the short term. In addition, drinking black,
caffeinated coffee (no additives, flavors or sweeteners) regularly was
linked to a lower risk of developing Type 2 diabetes. However, this
benefit may be due to compounds in coffee other than caffeine. More
research is needed to clarify the impact on Type 2 diabetes of caffeinated
coffee vs. various compounds in coffee.
- Effects
on cholesterol: Data from randomized clinical trials indicate
cafestol, a component in both caffeinated and decaffeinated coffee, was
associated with higher levels of low-density lipoprotein (also known as
“bad” cholesterol). Cafestol is present in unfiltered coffee (such as
espresso, French press, Turkish coffee or boiled coffee) but not present
in coffee brewed with paper filters or instant coffee. More research is
needed to understand which products have higher levels of cafestol and
their mechanisms.
- Effects
on heart rhythm: The most recent analyses of health measures with
self-reported information from participants have found that drinking 1-3
cups of caffeinated coffee per day was not associated with an increased
risk of atrial fibrillation or abnormal heart rhythm. However, caffeinated
coffee at that same level may be associated with more early beats from the
lower chamber of the heart, called premature ventricular contractions (or
PVCs). Very high doses of caffeine (such as those in caffeinated energy
drinks or energy shots) have been linked to abnormal heart rhythm in
people usually considered to have low cardiovascular disease risk, such as
healthy adults younger than age 30.
- Effects
on heart disease and stroke: Drinking 2-4 cups of caffeinated
coffee per day was linked to a lower risk of heart disease, heart failure
and stroke. However, drinking more than 4 cups of caffeinated coffee a day
may increase the risk of heart failure.
Not all sources of caffeine are the same
More research is necessary to investigate the different
health impacts of various types of caffeinated coffee and other products with
caffeine, such as tea, soda, energy drinks and energy shots, and foods. There
have been fewer studies focused on tea vs. coffee; however, tea has been
associated with reduced risk of atrial fibrillation, heart failure and stroke,
similar to caffeinated coffee. Energy drinks, bars, gels and caffeine-based
supplements often contain other added ingredients that may increase the absorption
of caffeine, may accelerate its effects on the body, may raise blood pressure
and increase the risk of cardiovascular harm.
More randomized controlled trials investigating the effects
of caffeine in coffee and other products that have caffeine on cardiovascular
health are needed to better understand how caffeine affects different people
and how different sources of caffeine impact heart health. The writing group
emphasized that there is also a need for research focused on caffeinated energy
drinks and other popular products containing caffeine. Due to the lack of
sufficient, rigorous data to develop guidance on recommendations for caffeine
intake, caffeine was not referenced in the Association’s 2026 Dietary Guidance to Improve Cardiovascular Health.
“Although research suggests that caffeine consumption may be
associated with certain cardiovascular benefits for some people, it’s important
to remember that there is no ‘one-size-fits-all’ strategy for safe caffeine
consumption. People can respond very differently to caffeine based on various
factors, such as age, medications, underlying health conditions, genetics and
how quickly their bodies metabolize it. What may be a reasonable amount for one
person could cause unwanted effects, such as heart palpitations, anxiety or
sleep disruption, in another. That’s why it’s important to pay attention to how
your body responds to caffeine and talk with your healthcare team about what is
right for you,” Marcus said.
This scientific statement was prepared by the volunteer writing group on behalf of the American Heart Association’s Council on Lifestyle and Cardiometabolic Health; the Council on Clinical Cardiology; and the Stroke Council. American Heart Association scientific statements promote greater awareness about cardiovascular diseases and stroke issues and help facilitate informed health care decisions. Scientific statements outline what is currently known about a topic and what areas need additional research. While scientific statements inform the development of guidelines, they do not make treatment recommendations. American Heart Association guidelines provide the Association’s official clinical practice recommendations.
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Additional Resources:
- Available
multimedia is on right column of release link, including video interview clips
with Gregory M. Marcus, M.D., M.A.S., FAHA. Scroll through
thumbnails for each clip topic and download option.
- Spanish news release (Including interview clips
in Spanish)
- After
July 20, 2026, view the manuscript
online.
- American
Heart Association news release: Top Health Experts Release New Drink Recommendations for
Kids and Teens’ Overall Health (Jan. 2025)
- American
Heart Association news release: Drinking coffee may help prevent mental decline in people
with atrial fibrillation (Dec. 2024)
- American
Heart Association news release: Drinking 2 or more cups of coffee daily may double risk of
heart death in people with severe hypertension (Dec. 2022)
- American
Heart Association news release: Drinking caffeinated coffee has both beneficial and
harmful short-term health effects (Nov. 2021)
- American
Heart Association health information: Caffeine and Heart Disease
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American Heart Association/American Stroke Association news on X @HeartNews
- Follow
news from the American Heart Association’s Circulation journal
on X @CircAHA
