Feeling your heart flutter, thump, or race, especially when relaxing, can be unsettling. This sensation, known as a “skipped heart beat” or palpitation, is frequent for many. While alarming, these moments are common and generally harmless. Understanding their causes can help alleviate concerns.
The Physiology of a Skipped Beat
A “skipped beat” sensation arises from an alteration in the heart’s electrical activity. Rather than missing a beat, the heart experiences an extra, premature contraction. These are premature atrial contractions (PACs) from the upper chambers, or premature ventricular contractions (PVCs) from the lower chambers.
Following a premature beat, the heart pauses briefly to reset its rhythm. This pause, known as a compensatory pause, allows the heart’s chambers to fill with more blood. When the next beat occurs, it feels more forceful, creating the sensation of a “skipped” beat followed by a powerful beat. Both PACs and PVCs are benign and can occur in healthy individuals.
Positional Triggers When Lying Down
Heart palpitations can become more noticeable when lying down due to physiological factors. One reason is increased bodily awareness; when resting, distractions are minimized, making individuals more attuned to internal sensations. This heightened perception can make otherwise unnoticed heartbeats more prominent.
Certain lying positions can influence the vagal nerve, which regulates heart rate and rhythm. Lying on the left side or stomach can exert pressure on this nerve, triggering or exacerbating palpitations. Digestive issues, such as acid reflux or gastroesophageal reflux disease (GERD), worsen when lying flat. The irritation from stomach acid can stimulate the vagal nerve, leading to heart palpitations.
Lying down can cause shifts in blood volume distribution. These fluid shifts can influence the heart’s workload and electrical stability, contributing to palpitations. The diaphragm’s proximity to the heart means pressure changes from certain body positions, or conditions like a hiatal hernia, can impact cardiac rhythm. These factors explain why palpitations feel more pronounced during rest.
Other Everyday Causes of Palpitations
Beyond positional influences, common factors can trigger heart palpitations. Lifestyle choices contribute, with stimulants like caffeine, alcohol, nicotine, and illicit drugs affecting heart rhythm.
Emotional states are a cause, as stress, anxiety, and panic attacks can activate the body’s “fight or flight” response, leading to a rapid or irregular heartbeat. Physical factors, such as dehydration, insufficient sleep, or intense exercise, can induce palpitations. Hormonal fluctuations during menstruation, pregnancy, or menopause, can alter heart rhythm sensitivity.
Over-the-counter and prescription medications, including decongestants and some asthma treatments, can cause palpitations. Nutritional imbalances, such as deficiencies in electrolytes like potassium or magnesium, are culprits. These electrolytes are important for heart function; their imbalance can disrupt electrical signals.
When to Seek Medical Advice
While heart palpitations are often harmless, certain accompanying symptoms warrant medical attention to rule out underlying conditions. Consult a doctor if palpitations occur alongside:
Chest pain or discomfort, indicating a serious cardiac issue.
Shortness of breath, particularly when resting or with minimal exertion.
Dizziness, lightheadedness, or fainting spells, signaling insufficient blood flow to the brain.
Unusual sweating not related to heat or activity.
Significant fatigue and weakness.
Palpitations that are frequent, prolonged, or worsening over time.
A family history of sudden cardiac death or a pre-existing heart condition increases the importance of seeking medical advice for new or changing palpitations.
What to Expect from a Doctor
When consulting a doctor for heart palpitations, the initial visit involves a detailed medical history and physical examination. The doctor will ask about the nature of your palpitations, including how often they occur, what triggers them, and any accompanying symptoms. This information helps in narrowing down potential causes.
Diagnostic tests evaluate heart function. An Electrocardiogram (ECG or EKG) records the heart’s electrical activity at rest, identifying abnormalities. To capture intermittent rhythms not occurring during a brief EKG, wearable monitors such as a Holter monitor (worn for 24-48 hours) or an event monitor (worn for longer periods, activated by symptoms) may be prescribed.
Blood tests check for conditions like thyroid dysfunction or electrolyte imbalances, which can contribute to palpitations. Often, no serious cause is found, providing reassurance. If a cause is identified, treatment may involve lifestyle adjustments, medication, or addressing the medical condition.
References
Heart Palpitations. Mayo Clinic. [Online]. Available: https://www.mayoclinic.org/diseases-conditions/heart-palpitations/symptoms-causes/syc-20373196. [Accessed 2025-08-21].
Premature Ventricular Contractions (PVCs). Cleveland Clinic. [Online]. Available: https://my.clevelandclinic.org/health/diseases/17441-premature-ventricular-contractions-pvcs. [Accessed 2025-08-21].
Palpitations and Your Vagus Nerve. Healthgrades. [Online]. Available: https://www.healthgrades.com/right-care/heart-health/palpitations-and-your-vagus-n. [Accessed 2025-08-21].
Heart Palpitations. American Heart Association. [Online]. Available: https://www.heart.org/en/health-topics/arrhythmia/what-is-arrhythmia/heart-palpitations. [Accessed 2025-08-21].
When to Worry About Heart Palpitations. Johns Hopkins Medicine. [Online]. Available: https://www.hopkinsmedicine.org/health/conditions-and-diseases/heart-palpitations. [Accessed 2025-08-21].
Heart Palpitations: Diagnosis and Treatment. NHS. [Online]. Available: https://www.nhs.uk/conditions/heart-palpitations/diagnosis-and-treatment/. [Accessed 2025-08-21].