Rapid Heartbeat

A rapid heartbeat (tachycardia) means your heart is beating faster than normal — typically more than 100 beats per minute at rest. It's often a normal response to exercise or stress, but persistent or sudden rapid heartbeats can have important causes.

Table of Contents

Quick Facts

  • Medical term: Tachycardia
  • ICD-10: R00.0
  • Normal resting: 60–100 bpm

When to Call 911

Call 911 for rapid heartbeat with:
  • Chest pain or pressure
  • Shortness of breath
  • Fainting or near-fainting
  • Severe weakness or sweating
  • Heart rate over 150 that won't slow

Common Causes

Non-cardiac

  • Exercise or recent activity
  • Anxiety, panic attack, or stress
  • Caffeine, alcohol, nicotine, stimulants
  • Fever or dehydration
  • Anemia
  • Hyperthyroidism
  • Low blood sugar
  • Pregnancy
  • Medications (some asthma, cold, ADHD medications)

Cardiac arrhythmias

  • Atrial fibrillation
  • Supraventricular tachycardia (SVT)
  • Ventricular tachycardia (more serious)
  • Inappropriate sinus tachycardia

Diagnosis

  • ECG during an episode (if possible)
  • Holter or event monitor
  • Echocardiogram
  • Blood tests — thyroid, blood count, electrolytes
  • Stress testing in selected patients

Treatment

Cause-specific:

  • Treat underlying conditions (thyroid, anemia)
  • Reduce caffeine and stimulants
  • Vagal maneuvers (deep breathing, cold water on face) for SVT
  • Medications (beta-blockers, calcium channel blockers, anti-arrhythmics)
  • Catheter ablation for recurrent SVT
  • Anticoagulation for atrial fibrillation

When to See a Doctor

See a doctor for episodes of unexplained rapid heartbeat at rest, especially if they cause dizziness, chest discomfort, or shortness of breath. Same-day evaluation is appropriate for new sustained tachycardia.

Related Symptoms

Palpitations

Awareness of heartbeat

 Heart Disease

Can cause arrhythmias

 Hyperthyroidism

Common reversible cause

 Anxiety

Frequent cause of rapid heart rate

Frequently Asked Questions

Is a heart rate of 120 dangerous?

It depends on the cause. With exercise or anxiety, 120 is usually normal. Persistent rates of 120 at rest, especially with symptoms, should be evaluated.

Why does my heart race when I lie down?

Lying down can briefly change blood flow and make heart sensations more noticeable. Persistent or symptomatic episodes warrant evaluation.

Medical Disclaimer: This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always consult a qualified healthcare provider with questions about a medical condition. If you are experiencing a medical emergency, call your local emergency number immediately.

References

  • American Heart Association. Tachycardia Patient Information.