What Causes Heart Palpitations?

Heart palpitations are a feeling of the heart beating faster, more forcefully, or irregularly. Normally the heart beats around 60 to 100 times per minute without us paying any attention. But heart palpitations may cause you to become aware of your own heartbeat. It can feel like a pounding or racing in the chest, throat, or neck or as though the heart skipped a beat.¹

Having heart palpitations can be an unsettling experience and probably makes you wonder why it's happening. Read on to learn about some common causes of heart palpitations and when to seek medical attention.

Heart Palpitation Causes

Most times, palpitations are not a sign of something serious.¹ There could be an underlying issue that needs to be addressed, though. Depending on what's causing you palpitations, you might be able to take measures to bring them to an end.

Dehydration

Dehydration happens when there's a decrease in total body water content due to fluid loss, a lack of fluid intake, or a combination of the two.² One symptom of dehydration is a rapid heart rate.³ Fast heart rate is also known as tachycardia, which is defined by a heart rate greater than 100 beats per minute.¹

During a period of dehydration, the heart has to work harder to pump blood.⁴ Dehydration can sometimes be accompanied by electrolyte imbalance, like low potassium, which is another cause of palpitations.⁵

Besides a change in heart rate, other signs of dehydration are⁶:

• Thirst
• Dark yellow urine
• Decreased urination
• Fatigue
• Weakness
• Sunken eyes
• Irritability

Tips for staying hydrated include^3,7:

• Drinking enough water every day
• Increasing fluid intake on hot days, when exercising, or during times of fluid loss such as sweating, diarrhea, or vomiting
• Avoid drinks that have sugar and caffeine
• Aiming for a pale yellow urine color

Caffeine

Caffeine is a stimulant, and taking in unusually large amounts—generally more than 10 grams—has been linked to arrhythmias, which are irregular heartbeats.⁸

However, studies have shown that in low and moderate doses, caffeine is not a significant cause of serious arrhythmias. In fact, a small 2021 trial continuously monitored heart activity for two weeks among 100 people who either did or did not have caffeine. The trial found no significant difference in arrhythmias between those who consumed or did not consume coffee. Still, those who drank coffee did show an increase in extra beats called premature ventricular complexes (PVCs).⁹ And palpitations may be felt with PVCs.¹⁰

Too much caffeine consumption can also cause a fast heart rate.¹¹ So if you are experiencing palpitations, it's worth seeing if decreasing your caffeine intake can make improvements.

Besides coffee, other sources of caffeine include¹¹:

• Tea
• Soda
• Energy drinks
• Chocolate
• Some supplements and powders
• Some headache medications

Alcohol

Alcohol can raise heart rate.¹² Alcohol can also increase the risk of atrial fibrillation, an irregular often fast heartbeat. Binge drinking has been found to have that connection, but so has having just one drink a day.^13,14 Drinking alcohol can also lead to dehydration and electrolyte disturbances, both of which are causes of palpitations.¹⁵

The American Heart Association recommends that those who drink alcohol do so in moderation, which is defined as no more than one drink per day for women and one to two drinks per day for men.¹³ If you experience palpitations, see if consuming less alcohol leads to an improvement.

Anxiety

Anxiety is one of the most common causes of heart palpitations. A fast heart rate can be caused by high levels of stress hormones and activation of the sympathetic nervous system that triggers the fight-or-flight response.¹⁶ People who experience panic attacks are familiar with the feeling of a racing and pounding heart that accompanies a sense of doom.¹⁷

While this feeling can be uncomfortable and scary, panic attacks are temporary and not a sign of an underlying heart problem. Once a healthcare provider rules out any physical cause of the palpitation, they might recommend visiting a mental health professional for help with managing anxiety.

Thyroid Problems

Thyroid hormones help control many of the body's main functions, including heart rate. Hyperthyroidism is a condition of increased thyroid hormone levels. High levels of thyroid hormone cause the heart to beat faster and may feel more forceful, giving the sensation of palpitations. Hyperthyroidism can also cause arrhythmias, like atrial fibrillation.¹⁸

Other symptoms of hyperthyroidism can include¹⁹:

• Restlessness and anxiety
• Weight loss
• Difficulty sleeping
• Change in hair or skin
• Changes in menstrual cycle

If you experience palpitations with these symptoms, see your health care provider who can order thyroid blood tests.

Fever

Another common—and temporary—cause of palpitations is fever. During a fever, the heart rate increases and can be perceived as a racing heart. One study among children showed that for every increase by 1 degree Celsius, heart rate increased by about 10 beats per minute.²⁰ Taking fever-reducing medications, like Tylenol (acetaminophen) or NSAIDs (non-steroidal anti-inflammatory drugs), and staying hydrated can help lower fevers to keep fever-related palpitations at bay.

Anemia

Anemia, or low blood count, is another cause of heart palpitations. When the levels of blood are low, regardless of the cause, the heart rate increases to compensate and bring oxygen and nutrients to the body. This can result in the feeling of a racing heart. Common causes of anemia are iron deficiency and blood loss.²¹

Other signs of anemia include:

• Shortness of breath
• Dizziness
• Weakness
• Headache
• Cold hands or feet
• Pale or yellow skin

Treatment depends on what's causing the anemia. Anemia can be caused by a number of factors, including iron deficiency, vitamin deficiency, or disease.²¹ Addressing the cause can help with symptoms like heart palpitations.

Medications

Many medications have palpitations as a side effect^16,22:

• Thyroid medication
• Diuretics
• Decongestants
• Asthma inhalers
• Antidepressants
• Antipsychotics
• Stimulants (such as medications for ADHD)
• Certain blood pressure medications
• Certain herbs and supplements

Talk with a health care provider about the medications you take, their potential side effects, and possible alternatives.

Long COVID

Palpitations are a common symptom of post-acute sequelae of COVID-19 infection (PASC). A substantial number of people with previous COVID-19 infection have reported racing heart and various other symptoms weeks to months after infection. People may experience fast heart rates with standing or with minimal levels of activity, resulting in exercise intolerance. Ongoing research is being done to determine the prognosis and best treatment strategies.²³

Low Oxygen Levels

Low oxygen levels in the blood, also known as hypoxemia, can lead to palpitations.²⁴ Blood oxygen levels can become low for various reasons²⁵:

• Lung infection, like pneumonia
• High altitude
• Lung disease
• Heart problems (heart failure, certain heart defects)
• Pulmonary embolism
• Impaired breathing mechanism (such as with sedative medications or coma)

Heart Disease

While palpitations may have any number of causes unrelated to the heart, some of the more serious forms of palpitations are from problems with the heart itself. These can be due to problems with various parts of the heart like the muscle, electrical system, chambers, and valves:

• Heart rhythm problems
• Heart attack
• Scar in the heart from a previous heart attack
• Congenital heart disease
• Heart valve problems
• Heart failure
• Myocarditis (heart muscle inflammation)

Low Blood Sugar

Hypoglycemia, or low blood sugar, happens when your blood sugar levels fall below what is considered a safe range. A fast heartbeat is one of the symptoms of low blood sugar. This happens because low blood sugar causes the body to release adrenaline, the hormone associated with the fight-or-flight response. The adrenaline is what can cause a racing heart along with other symptoms of low blood sugar like sweating, tingling, and anxiety.²⁶

Other signs of low blood sugar include:

• Feeling shaky, lightheaded, or dizzy
• Confusion
• Hunger
• Nausea
• Color draining from the skin
• Headaches
• Clumsiness

There are actions you can take, such as eating carbohydrates, to raise your blood sugar to a safe level. That will make the thumping heartbeat subside.²⁶

When to Visit a Health Care Provider

If this is your first time experiencing heart palpitations, visit a health care provider. They can make sure it's nothing serious causing the palpitations. If you've had heart palpitations in the past and they are now different, that's another reason to visit a provider.¹

Whether you've had palpitations before or not, you should seek immediate medical care if they are accompanied by symptoms like chest pain, loss of consciousness, shortness of breath, unusual sweating, dizziness, and lightheadedness.¹

Summary

Many causes of heart palpitations are harmless. Once the cause is addressed, such as drinking water to reverse dehydration, calming anxiety, or decreasing caffeine intake, the palpitations will subside. But some causes of palpitations can be a sign of heart disease or other serious conditions. Whatever the cause, palpitations can be unnerving. It's time to see a healthcare provider if you are concerned about your palpitations. Worrisome signs like fainting or near-fainting, chest discomfort, or shortness of breath are all reasons to seek medical attention right away.

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