Heart Palpitations: Causes, Symptoms, and When to Worry

What Are Heart Palpitations?

Palpitations are the conscious awareness of your own heartbeat. They are symptoms, not diagnoses — a perception that the heart is beating abnormally in rate, rhythm, or force. People describe them as:

• Fluttering in the chest
• Heart "skipping a beat" or pausing
• Rapid or racing heartbeat
• Pounding or thumping sensation
• Heart "flopping" or turning over
• Irregular heartbeat felt in the throat or neck

The sensation can occur in the chest, throat, or neck. Duration ranges from a single beat to hours.

How Common Are Palpitations?

A systematic review in Heart journal (Raviele et al., 2011) found that palpitations are the second most common cardiac complaint after chest pain in primary care settings. Population studies report lifetime prevalence of 10–16%. In a 2012 cohort study (Annals of Internal Medicine), Weber & Kapoor found that 43% of palpitation cases in primary care had a cardiac cause, 31% psychiatric (anxiety/panic), 10% miscellaneous (thyroid, anemia, drugs), and 16% were never identified.

Most Common Causes of Palpitations

1. Premature Beats (Most Common — Usually Benign)

The most common cause of "skipped beat" palpitations is premature atrial contractions (PACs) or premature ventricular contractions (PVCs). These are extra heartbeats that occur slightly out of rhythm, followed by a brief pause and then a stronger-than-usual beat — which is the "thud" most people feel.

PACs and PVCs occur in virtually everyone: Holter monitor studies find PVCs in over 75% of structurally normal hearts over 24 hours. They are triggered by caffeine, alcohol, stress, dehydration, and fatigue. In people without structural heart disease, frequent PVCs (<10,000/day) carry no increased mortality risk.

2. Anxiety and Panic Disorder

Psychological stress activates the sympathetic nervous system, releasing adrenaline (epinephrine) which directly increases heart rate and contraction force. During a panic attack, heart rate can reach 120–180 bpm — producing prominent palpitation awareness. A 2016 meta-analysis (Katerndahl, Journal of the American Board of Family Medicine) found anxiety disorders in 28–40% of patients presenting with unexplained palpitations.

Key distinguishing feature: anxiety palpitations typically occur in context of other symptoms (breathlessness, tingling, dread), during emotional stress, and resolve completely between episodes.

3. Caffeine

Caffeine blocks adenosine receptors and increases circulating catecholamines, directly promoting atrial and ventricular ectopy. A dose-response relationship exists: consumption above 300 mg/day (approximately 3 cups of coffee) significantly increases PAC and PVC frequency in sensitive individuals. Importantly, a large prospective study (Kim et al., JACC, 2021) found no association between moderate habitual coffee intake and increased arrhythmia risk in most people — but individual sensitivity varies considerably.

4. Atrial Fibrillation (AF)

AF is the most clinically significant cause of palpitations — and the most important to identify. In AF, the atria fire chaotically at 350–600 impulses/min, producing an irregularly irregular ventricular response, typically 100–160 bpm. Globally, AF affects 33–37 million people and is associated with 5× higher stroke risk (Wolf et al., Stroke).

AF palpitations are typically described as irregularly irregular — the heart seems to beat "randomly." They often occur in episodes lasting minutes to days and may be associated with fatigue, exercise intolerance, and mild dyspnea.

5. Supraventricular Tachycardia (SVT)

SVT is a family of arrhythmias arising above the ventricles — the most common being AVNRT (AV nodal re-entrant tachycardia). SVT produces sudden-onset regular rapid heart rate of 150–250 bpm that terminates abruptly. Episodes often last minutes to hours. SVT affects approximately 2.29 per 1,000 people and is more common in women and younger adults.

The hallmark description: "My heart suddenly switches to a high speed — then just stops." The abrupt onset and offset distinguish SVT from sinus tachycardia (which accelerates and decelerates gradually).

6. Thyroid Disorders

Hyperthyroidism (excess T3/T4) is a classic and underdiagnosed cause of persistent palpitations. Thyroid hormones directly increase heart rate and cardiac contractility. The combination of resting tachycardia, palpitations, weight loss, heat intolerance, and tremor should prompt immediate TSH measurement. Hypothyroidism can also cause palpitations, particularly in patients on thyroid replacement therapy.

7. Anemia

Hemoglobin deficiency reduces oxygen-carrying capacity, forcing the heart to increase output (higher rate and stroke volume) to compensate. Iron deficiency anemia — the most prevalent nutritional deficiency worldwide — commonly presents with palpitations, dyspnea on exertion, and fatigue. A complete blood count (CBC) rules this out quickly.

8. Dehydration and Electrolyte Imbalances

Low magnesium, potassium, or calcium can destabilize cardiac membrane potentials, increasing ectopic beat frequency. Hypomagnesemia is particularly associated with PVCs and SVT. Severe dehydration reduces plasma volume, triggering reflex tachycardia. These are among the most reversible causes of palpitations.

9. Medications and Substances

• Beta-agonist inhalers (albuterol, salbutamol) — direct chronotropic effect; palpitations are a known side effect
• Decongestants (pseudoephedrine, phenylephrine) — sympathomimetic; common OTC trigger
• Thyroid hormone replacement — palpitations indicate suprapherapeutic dosing
• Alcohol — "holiday heart syndrome": AF after acute alcohol intake, even without chronic use
• Cannabis — THC increases sympathetic tone; AF and SVT are reported complications
• Energy drinks — high caffeine + taurine combination: associated with SVT in case series

When Palpitations Are Not an Emergency (But Still Need Evaluation)

Schedule a non-urgent GP or cardiologist appointment for:

• Palpitations occurring more than once per week
• Episodes lasting more than 10 minutes regularly
• Palpitations during exercise (not anxiety-related)
• Family history of sudden cardiac death or arrhythmia
• New palpitations after starting a medication

How Palpitations Are Diagnosed

The diagnostic approach depends on frequency and duration of episodes:

Reducing Palpitations: Evidence-Based Approaches

Lifestyle Modifications (Strongest Evidence)

• Reduce caffeine: trial 2–4 weeks caffeine-free; many patients with PAC/PVC palpitations see significant improvement
• Limit alcohol: even 1–2 drinks triggers palpitations in susceptible individuals; holiday heart is well-documented
• Stay hydrated: 2–3 L of water daily eliminates dehydration-related ectopy
• Correct sleep: sleep deprivation increases sympathetic tone and ectopic beat frequency
• Slow breathing exercises: diaphragmatic breathing at 6 breaths/min significantly increases vagal tone, suppressing ectopy (Lehrer et al., 2000)
• Magnesium supplementation: 300–400 mg/day of magnesium glycinate reduces PVC frequency in deficient individuals — discuss with a physician first

The Valsalva Maneuver

For SVT episodes, bearing down (as if having a bowel movement) increases vagal tone and can terminate SVT within seconds. The modified Valsalva position — lying supine with legs raised immediately after — nearly doubles the termination rate from 17% to 43% compared to standard position (Appelboam et al., The Lancet, 2015).