Sleep may be a trigger of AFib. Some people may be more prone to experiencing AFib symptoms at night, including heart palpitations, a fast heartbeat, and fluttering sensations in the chest.

Aside from palpitations, other symptoms of AFib may include dizziness, sweating, and shortness of breath.

Sleep position, sleep apnea, and other sleep impairments may increase the risk of nighttime AFib.

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According to the American Heart Association (AHA), atrial fibrillation (AFib) does not always cause symptoms. When symptoms do occur, they may include one or more of the following:

A 2021 study notes that sleep is a well-known trigger for AFib. As such, people may be more likely to experience the above symptoms at night.

Sleep is a common trigger for AFib episodes, meaning AFib symptoms may also be more common at night.

Factors that may contribute to night-time AFib symptoms include sleep position, sleep apnea, and impaired sleep.

Sleep position

The 2021 study previously referenced found that sleep position may affect AFib. In this study involving 94 people with AFib, 77% experienced symptoms during the night, or while falling asleep or waking.

Moreover, 22% of people reported that a specific body position triggered their AFib. Of these individuals:

  • 57% reported that lying on their left side triggered AFib
  • 33% reported that lying on their back triggered AFib
  • 10% reported that lying on their right side triggered AFib
  • 5% reported that lying on their front triggered AFib

The study authors noted that a left-sided sleeping position increases the size of the heart’s left atrium and the right pulmonary veins that carry oxygenated blood from the lungs to the left atrium. This increases stress on the heart, potentially triggering AFib in individuals more likely to experience the heart event.

Sleep apnea

As the American Sleep Apnea Association (ASAA) explains, sleep apnea (SA) is a medical condition in which a person repeatedly stops and starts breathing during sleep.

According to a 2021 literature review, there is a strong association between SA and AFib. While the reason for this association remains unclear, scientists believe that SA causes over-activity of the autonomic nervous system (ANS).

The ANS is the part of the nervous system that regulates involuntary physiological responses, such as:

  • heart rate
  • respiration
  • blood pressure

Impaired sleep

According to the British Cardiovascular Society (BCS), observational data suggest that impaired sleep may increase a person’s risk of developing AFib, and may also increase the risk of AFib episodes in people who already have the condition.

This is because impaired sleep can disrupt the hormones and metabolic processes that contribute to a normal heart rhythm.

Sleep impairments associated with AFib include:

  • taking longer to fall asleep
  • waking up frequently throughout the night
  • spending less time spent in rapid eye movement (REM) sleep
  • sleeping for less than 6 hours, or more than 8 hours per night
  • working night shifts

People who experience symptoms of AFib at night or at any other time of day should contact a doctor for a diagnosis.

As the AHA explains, while AFib itself is not harmful, it can increase the risk of cardiovascular complications, such as heart attack and stroke.

The AHA adds that the following lifestyle changes may help to reduce these risks:

A person should contact a doctor if they experience any symptoms of AFib.

According to the Centers for Disease Control and Prevention (CDC), a person should contact emergency services as soon as possible if they experience any of the following symptoms, which could indicate a heart attack:

  • chest pain or discomfort
  • chest pain or discomfort that spreads to the arms, back, neck, or jaw
  • shortness of breath

As AFib increases the risk of having a stroke, people should be aware of the signs and contact emergency services if they notice any.

Signs of a stroke include sudden:

  • confusion or trouble speaking
  • vision problems
  • trouble walking, dizziness, or loss of balance or coordination
  • severe headache

Is it a heart attack?

Heart attacks occur when there is a lack of blood supply to the heart. Symptoms include:

  • chest pain, pressure, or tightness
  • pain that may spread to arms, neck, jaw, or back
  • nausea and vomiting
  • sweaty or clammy skin
  • heartburn or indigestion
  • shortness of breath
  • coughing or wheezing
  • lightheadedness or dizziness
  • anxiety that can feel similar to a panic attack

If someone has these symptoms:

  1. Dial 911 or the number of the nearest emergency department.
  2. Stay with them until the emergency services arrive.

If a person stops breathing before emergency services arrive, perform manual chest compressions:

  1. Lock fingers together and place the base of hands in the center of the chest.
  2. Position shoulders over hands and lock elbows.
  3. Press hard and fast, at a rate of 100 to 120 compressions per minute, to a depth of 2 inches.
  4. Continue these movements until the person starts to breathe or move.
  5. If needed, swap over with someone else without pausing compressions.

Use an automated external defibrillator (AED) available in many public places:

  1. An AED provides a shock that may restart the heart.
  2. Follow the instructions on the defibrillator or listen to the guided instructions.

The following sleeping tips may help reduce the risk of night-time AFib in people who have this condition.

  • avoiding sleeping on the left side
  • following a consistent sleep-wake schedule
  • getting around 8 hours of sleep per night
  • sleeping in a cool, quiet, and comfortable environment
  • avoiding stimulants, such as alcohol, nicotine, or caffeine, before bedtime

Individuals with sleep apnea and AFib may find that treating the sleep apnea helps to reduce episodes of night-time AFib. The National Institutes of Health (NIH) provides the following lifestyle changes to help manage sleep apnea:

  • staying physically active, such as exercising regularly
  • maintaining a healthy weight
  • quitting smoking if you smoke
  • using a breathing device, such as a continuous positive airway pressure (CPAP) machine to help keep the airways open during sleep
  • wearing custom-fit oral devices during sleep to help prevent airway blockages
  • receiving orofacial therapy to help strengthen the muscles of the face, tongue, and upper airway

Why does AFib get worse at night?

The following factors may cause AFib to worsen at night:

  • sleeping on the left side, which increases pressure on the left atrium and left pulmonary vein, triggering AF
  • having sleep apnea, which can cause ANS hyperactivity and associated changes to heart rhythm
  • experiencing sleep impairments, which can disrupt the hormones and metabolic processes that play a role in normal heart rhythm

What position should you sleep in with AFib?

According to a 2021 study, the best sleep position for people with AFib is sleeping on the front, since only 5% of people who slept in this position reported experiencing night-time AFib.

People who do not feel comfortable sleeping on their front may prefer to sleep on their right side. According to the 2021 study, only 10% of people who slept in this position reported experiencing night-time AFib.

Symptoms of AFib may include sweating, dizziness, and shortness of breath. For some people, these symptoms may occur or worsen at night.

Factors that may contribute to night-time AFib include sleep apnea, other sleep impairments, and lying on the left side during sleep.

Things people can do to reduce night-time AFib include sleeping on their front or on their right side, treating sleep apnea, and practicing good sleep hygiene.

While AFib itself is not harmful, the condition can increase the risk of cardiovascular events, such as stroke and heart attack. As such, anyone who experiences symptoms of AFib should see promptly see a doctor for a diagnosis and appropriate treatment.