Caffeine and Your Heart: How Much Caffeine Is Too Much?

You may wonder how much caffeine is too much if you have ever had enough coffee, tea or energy drinks to make your head buzz and your heart beat like a drum. You might also worry about what caffeine is doing to your heart if you sometimes feel chest pain after drinking tea or coffee.

"Although it is theoretically possible that you could have chest pain from caffeine, caffeine is not considered a cause of chest pain," says John V. Higgins, MD, assistant professor of cardiovascular medicine at the University of Nebraska Medical Center in Omaha.

Caffeine doesn't cause chest pain for most people, especially when safe levels (up to 400 milligrams per day, per the Mayo Clinic) are consumed.

​Read more:​ What Really Happens to Your Body When You Have Caffeine

Most people drink caffeine because it stimulates the central nervous system and acts as a pick-me-up. It also stimulates acid in your stomach, increases blood pressure and can make your heart beat faster, according to the U.S. National Library of Medicine (NLM).

"If a person was very sensitive to caffeine, it could cause the heart to beat fast and blood pressure to go up enough to decrease blood flow to the heart and cause chest pain. These effects on heart rate and blood pressure are not likely for most people. If you experience chest pain from drinking tea or coffee, it is more likely to be acid indigestion," Dr. Higgins says.

Caffeine does not cause breathing problems, according to the Harvard T.H. Chan School of Public Health. In fact, it can improve breathing because it relaxes and opens breathing passages. It has been shown to improve asthma symptoms, and it has been used as treatment for breathing problems in premature babies.

Up to 400 milligrams of caffeine a day is safe for most healthy people, which is about the amount of caffeine in 4 cups of coffee, Mayo Clinic says. Too much caffeine, however, can cause unpleasant symptoms, including:

• Nervousness and irritability.
• Headache.
• Insomnia.
• Heartburn.
• Tremor.
• Frequent urination.
• Rapid heart rate.

The amount of caffeine that causes these symptoms can be different for different people. Some people with caffeine sensitivity or intolerance may have unpleasant symptoms from less than 400 milligrams. People who drink a lot of caffeine may have no symptoms, even if they go over 400 milligrams, per Mayo Clinic. It varies person-to-person.

"Some people who are not used to caffeine or may be more sensitive may have palpitations and should avoid caffeine, but studies show that even 6 cups of coffee per day is not associated with any significant heart problems," Dr. Higgins says.

The American College of Cardiology (ACC) warns that energy drinks may be one form of caffeine to be avoided. These drinks have higher levels of caffeine and may include other energy-boosting ingredients. Energy drinks are associated with numerous health problems, including heart attacks, the ACC says.

"I advise everyone to stay away from these drinks," Dr. Higgins says. "If you have a history of heart attack or you have been diagnosed with coronary artery disease, ask your doctor how much caffeine is safe for you."

Caffeine may be more likely to cause palpitations or high blood pressure when combined with certain medications. The Mayo Clinic says to avoid caffeine along with an over-the-counter decongestant that contains ephedrine, drugs that contain theophylline and the herbal supplement echinacea. All of these can increase the risk of unpleasant caffeine effects.

Finally, according to the NLM, people with certain conditions may need to avoid or limit caffeine, including:

• Women who are pregnant or breastfeeding.
• Children and teens.
• People with insomnia.
• People with acid reflux or ulcer disease.
• People with anxiety.

According to the American Heart Association, coffee is an excellent source of antioxidants. Coffee drinking has been linked to a lower risk of heart disease, and Dr. Higgins says some studies have shown it may help people live longer.

​Read more:​ 8 Health Benefits of Coffee That'll Justify Your Java Obsession (and How to Brew the Best Cup)