Racing Heart After Coffee: What Caffeine Does and When to Get Help

Key takeaways

• Increased heart rate, palpitations and higher blood pressure are on the FDA list of signs of too much caffeine.
• Palpitations with chest pain, shortness of breath, feeling faint or fainting, or palpitations that do not go away, need emergency help.
• In a 2023 randomized trial, coffee did not significantly increase extra beats from the upper heart chambers but was linked to more extra beats from the lower chambers.
• Caffeine peaks in the blood within about an hour and can be felt for 4 to 6 hours, and longer in slow clearers.
• If coffee keeps setting off palpitations, cut down gradually and talk to a doctor, especially if you have a heart condition.

Call for help now if a racing heart after coffee comes with these signs

Do not try to wait these out, even if you are sure you just had too much coffee. The NHS says to call emergency services or go to the emergency department if you have palpitations that do not go away, or palpitations together with any of the symptoms below. MedlinePlus says anyone with signs of a caffeine overdose should seek medical help right away.

If these symptoms happened but have now stopped, the NHS still advises getting an urgent appointment rather than waiting (in the UK, through your GP surgery or 111). It also says not to drive yourself to the emergency department: ask someone to take you, or call an ambulance.

• Chest pain.
• Shortness of breath or trouble breathing.
• Feeling faint or fainting.
• Palpitations that do not go away.
• An irregular heartbeat, confusion, seizures, vomiting or fever.
• You took caffeine pills, powder or energy shots, or you cannot tell how much you had. The FDA estimates toxic effects such as seizures can occur with rapid intake of around 1,200 mg.

When heart palpitations after caffeine need a doctor visit

Even when you feel well otherwise, some patterns are worth getting checked. The NHS advises seeing a GP if palpitations keep coming back or happen more often, last longer than a few minutes, or if you have a heart condition or a family history of heart problems. The FDA also advises talking with a health professional about your caffeine use if you notice symptoms such as an increased heart rate or palpitations.

MedlinePlus advises people with arrhythmia (a heart rhythm problem), high blood pressure or anxiety, and people taking certain medicines, to check with their health care provider about whether to limit or avoid caffeine. If any of these apply to you, ask your doctor or pharmacist what makes sense for you rather than relying on general advice.

Why caffeine can make your heart pound

Caffeine works mainly by blocking adenosine receptors, which makes you more alert and stimulates the body. In a controlled study of 102 light caffeine users given 50 to 450 mg, caffeine raised blood pressure and produced feelings of arousal, and MedlinePlus notes that caffeine increases blood pressure. A faster heart rate is listed by both the FDA and MedlinePlus among the effects of too much caffeine.

Anxiety adds to the picture. The NHS lists stress and anxiety, lack of sleep and strenuous exercise, as well as caffeine, alcohol and nicotine, among the common causes of palpitations, so a big coffee on a stressful day can involve several triggers at once. That is one reason it can be hard to know what caused a racing heart, and why our guide on panic attacks or too much coffee treats them together.

How much you had matters most for most people. FDA figures put a 12-fl oz brewed coffee at 113 to 247 mg and an energy drink at 41 to 246 mg, and the FDA notes that people differ widely in how sensitive they are to caffeine.

What heart-rhythm studies show about coffee and extra heartbeats

The strongest recent study is a 2023 randomized trial in the New England Journal of Medicine. One hundred adults (average age 39, 51% women) wore a continuous heart monitor for 14 days, and daily text messages told them at random to drink caffeinated coffee or avoid caffeine. Coffee did not significantly increase premature atrial contractions, extra beats from the upper chambers of the heart. It was linked to more premature ventricular contractions, extra beats from the lower chambers: about 154 a day on coffee days versus 102 on caffeine-free days.

An earlier meta-analysis of seven human studies found no significant effect of caffeine on ventricular premature beats over 24 hours. Put together, the evidence is mixed. It does not show that caffeine causes dangerous rhythms in healthy people, and it does not show that caffeine has no effect on the heart. Neither study tells you how caffeine affects someone with a heart condition, so their results should not be stretched to cover that.

How long a caffeine racing heart can last, including at night

MedlinePlus says caffeine reaches its peak blood level within an hour and that you may feel its effects for 4 to 6 hours. The European Food Safety Authority puts the average half-life at about 4 hours in healthy adults, with a range of 2 to 8 hours. The calculator above shows how much of a dose may still be in your body at a given time.

Caffeine also lingers longer than people expect. In a small lab study of nine healthy men, 200 mg taken at about 7 a.m. was still measurable in saliva at 11 p.m., at roughly one-sixth of its peak level. If you notice your heart pounding when you lie down at night, an afternoon coffee or energy drink may still be in play. Our guide to waking up at night after caffeine covers the sleep side.

Knowing caffeine takes hours to clear is not a reason to sit with symptoms. The NHS advises a GP visit for palpitations that last longer than a few minutes, and emergency help if they do not go away or come with the warning signs above.

Steps that may help a racing heart after too much coffee

If you have none of the warning signs and you know you overdid it, these steps do not lower your caffeine level, but they avoid making things worse:

• Stop all caffeine, including tea, cola, energy drinks, pre-workout and caffeinated medicines or supplements.
• Avoid nicotine and alcohol, which the NHS lists alongside caffeine as palpitation triggers.
• Sit down somewhere quiet and breathe slowly. calmness.today has a free guided 4:6 breathing reset if it helps to follow along.
• Skip a hard workout meant to burn off the caffeine: the NHS lists strenuous exercise as a common cause of palpitations. See can you flush caffeine out for what does and doesn't change clearance.
• If symptoms are not easing, or you feel worse, get medical advice rather than waiting.

Cutting back if coffee keeps setting off heart palpitations

When palpitations are not caused by a health condition, the NHS says cutting out triggers like caffeine can help. That makes it worth getting checked first, then trying less caffeine.

If you drink caffeine daily, cut down gradually. The FDA advises this because withdrawal can be unpleasant, and in experimental studies about half of people got a headache when they stopped caffeine. Switching some cups to decaf, which typically has 2 to 15 mg per 8-fl oz cup, or to green tea, lowers the dose while keeping the habit. Our caffeine withdrawal guide explains what to expect.

Common questions