Many factors can cause a person to wake up with a racing heart, including stress, sleep deprivation, sleep apnea, and changes in blood sugar levels.

Sometimes, upon waking, it may feel as though the heart is beating very fast or pounding in the chest. A person may also feel shaky or anxious when this happens.

Tachycardia is the name for a rapid heart rate. When a person has palpitations or arrhythmia, their heart rate becomes irregular. One reason for this is atrial fibrillation (A-fib). If a person has tachyarrhythmia, their heart beats irregularly and fast — over 100 beats per minute.

A racing or irregular heart rate is not always a matter for concern, but it can indicate a medical condition, such as heart disease, diabetes, a sleep disorder, or anemia. If a person’s heart rate changes, it is best to seek medical advice to rule out any serious issues.

This article looks at why a person may wake up with their heart racing and when to see a doctor.

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Anxiety and stress levels can trigger the release of hormones in the blood that raise heart rate. Statistics suggest that around 31% of heart palpitation cases may be due to a mental factor such as stress, anxiety, or internal conflict.

People with stress or anxiety may also notice other symptoms, including:

Find 10 natural remedies for stress and anxiety here.

Blood sugar levels can affect heart rate.

One symptom of high blood glucose, or hyperglycemia, is a rapid heart rate. For people with diabetes, consuming sugary foods before a nap or before bed may cause them to wake up with their heart racing.

Research also suggests that low blood sugar levels can increase the risk of arrhythmia. Low blood sugar triggers the release of epinephrine in the body. Epinephrine is a hormone that has a link to the “fight-or-flight” response, which can affect heart rate.

How can I manage my glucose levels?

Some experts say that caffeine consumption can increase heart rate. Caffeine is present in coffee, tea, soda, and some medications.

Research suggests this may be true for some people, specifically those with a particular gene.

However, a 2021 study that looked at data for more than 300,000 people found no evidence that caffeine increased the risk of changes in heart rate. Instead, the findings suggested that drinking coffee might reduce this risk by 3%.

The American Heart Association advises people to consume coffee in moderation because scientific studies have not yet confirmed these findings.

Other effects of caffeine consumption include:

  • restlessness
  • anxiety
  • trouble falling or staying asleep
  • headache

Can you overdose on caffeine?

Dehydration can affect the heart and may lead to an irregular heartbeat. When there is too little fluid in the body, this is known as hypohydration. It can lead to low blood pressure. The body tries to compensate by producing additional hormones to speed up the heart.

Symptoms of dehydration include:

What is a dehydration headache?

A high consumption of alcohol can lead to arrhythmia and a rapid heart rate, research shows.

It takes several hours for the body to process large amounts of alcohol, and the effects of drinking in the evening can continue throughout the night and into the morning.

After consuming alcohol, a person may also experience:

  • increased blood pressure
  • mild dehydration
  • fragmented sleep
  • gastrointestinal disturbances, such as pain and nausea
  • inflammation
  • feelings of restlessness, anxiety, and irritability
  • muscle aches
  • headache
  • fatigue
  • sensitivity to light
  • sweating

What happens if you drink a lot of alcohol?

A nightmare is a disturbing dream. Nightmares can cause physical symptoms, such as respiratory difficulties. This may cause a person to wake up with a racing heart. They may also experience sweating and shaking.

Night terrors can also cause a person to wake up feeling panicked and with a racing heart. Experts have found links between night terrors, vocalizations, a rapid heart rate, and breathing problems. When a person wakes up, they may not remember the specific details of these episodes.

How do night terrors affect toddlers?

Narcolepsy is a sleep disorder that includes:

It also has links with diabetes, heart disease, high cholesterol, and high blood pressure. Most people’s heart rate dips when they sleep. In people with narcolepsy, it may increase.

A lack of sleep may also cause a person to feel that their heart rate is higher than usual.

Sleep disturbances or not getting enough sleep can cause a number of health issues. The next day, the person may also feel that their heartbeat is slightly faster.

According to the Radiological Society of North America, just 24 hours of sleep deprivation can lead to cardiac disturbances, such as an increased heart rate and high blood pressure.

Sleep apnea is when a person repeatedly stops breathing while they sleep. This can lower oxygen levels and put extra stress on the heart. It may also cause a racing heartbeat.

People with sleep apnea can also:

Research from 2017 suggests sleep apnea may also contribute to new appearances of A-fib.

What are the symptoms of sleep apnea?

People with iron-deficiency anemia do not have enough healthy red blood cells circulating in their bodies. Various symptoms can result, including changes in heart rate.

Other symptoms of anemia are:

  • headaches
  • general fatigue
  • shortness of breath
  • difficulty concentrating

How can you increase your red blood cell count?

Waking up with a racing heart may also be due to the menstrual cycle. More specifically, a racing heart can occur due to shifts in estrogen and progesterone levels.

A 2013 study found higher variability in heart rate in females before menopause than in females after menopause or males, suggesting that hormonal fluctuations play a role.

Around menopause, declining estrogen levels can lead to palpitations. Palpitations may also occur during hot flashes.

What is the link between palpitations and menopause?

Changes in the body’s temperature, for example, during a fever, may also cause changes in heart rate.

A 2021 study of people in ICU found that for every 33.8°F body temperature rise in females, their heart rate increased by 9.5 beats per minute on average. For males, it was 7.2 beats.

Alongside a fever, a person may have:

  • sweating
  • chills
  • general fatigue
  • achy or sore muscles

How can you treat a fever?

A fast or irregular heart rate may be a side effect of various medications, including:

  • antiarrhythmic drugs, such as adenosine
  • some anticancer drugs, for example, trastuzumab
  • anticonvulsants, such as lacosamide
  • some antidepressants, for instance, citalopram
  • herbal remedies, such as Ginkgo biloba

Anyone taking medications should first speak with a doctor about possible side effects that may affect the heart.

A person should seek help for any change in heart rhythm or heart rate because it can be a sign of an underlying problem.

A doctor may carry out tests and order a Holter monitor. This records heart activity. It can monitor heart rhythms and may help with diagnosis.

A person needs urgent medical attention if they have a history of heart disease or signs of a heart attack, such as chest pain.

Learn some tips for stopping heart palpitations here.

Here are some questions people often ask about heart palpitations at night.

I cannot sleep because of palpitations. What should I do?

Anyone who often notices changes in heart rhythm should seek medical advice as they may be a sign of an underlying health problem. If palpitations are due to stress, breathing exercises or meditation may help manage them. If a person is taking medication for a heart condition and has palpitations, they should contact a doctor. The medication may need a review.

Why do I get palpitations at night?

This can happen if a person has a heart condition, such as atrial fibrillation. Other possible causes of arrhythmia or a rapid heart rate include sleep apnea, narcolepsy, a lack of sleep, alcohol use, stress, changes in blood sugar, hormonal fluctuations, and so on.

Waking up with a racing heart is not necessarily a cause for concern, but it is best to seek medical advice.

A doctor may determine that no treatment is necessary, but they may advise a person to do tests or see a specialist to investigate further. There may be an underlying issue that needs attention.