Why is my heart racing when I'm resting?

Detailed Explanation

Feeling your heart race when you're sitting still can be alarming. The medical term is tachycardia (heart rate over 100 beats per minute at rest). While often benign, it's important to understand the causes and know when to seek help.

Normal resting heart rate varies: | Category | Resting Heart Rate | |----------|-------------------| | Normal Adult | 60-100 bpm | | Well-Trained Athlete | 40-60 bpm | | Tachycardia | Over 100 bpm | | Concerning | Over 150 bpm at rest |

The Most Common Cause: [Anxiety](/condition/anxiety)

• Anxiety and stress trigger your "fight-or-flight" response:
• Adrenaline and cortisol flood your system
• Heart rate increases to prepare for action
• Blood pressure rises
• You may feel chest tightness, shortness of breath
• Creates a cycle: racing heart causes more anxiety

• 1. Caffeine and Stimulants
• Coffee, tea, energy drinks
• Chocolate (contains caffeine)
• Pre-workout supplements
• Some medications (pseudoephedrine, ADHD meds)
• Effect can last 4-6 hours

• 2. Dehydration
• Blood volume drops when dehydrated
• Heart beats faster to compensate
• Solution: drink more fluids
• Especially after exercise, in hot weather

• 3. Sleep Deprivation
• Poor sleep affects heart rate variability
• Increases stress hormones
• Creates hyperarousal state
• Irregular sleep patterns disrupt rhythm

• 4. Alcohol and Substances
• Alcohol increases heart rate
• "Holiday heart syndrome" - racing heart after heavy drinking
• Nicotine stimulates the heart
• Cannabis can cause tachycardia

• 5. Intense Emotions
• Excitement, anger, fear
• Grief or emotional stress
• Even positive excitement (falling in love!)

• [Thyroid Problems (Hyperthyroidism)](/condition/graves-disease)
• Overactive thyroid speeds up metabolism
• Heart rate increases as part of overall "revving"
• Other signs: weight loss, heat intolerance, tremor
• Simple blood test (TSH) diagnoses it
• Very treatable once identified

• [Anemia](/condition/anemia)
• Low red blood cells mean less oxygen delivery
• Heart beats faster to compensate
• Common in women with heavy periods
• Also causes fatigue, pale skin, shortness of breath
• Blood test confirms diagnosis

Heart Arrhythmias Various electrical problems in the heart:

| Arrhythmia | What It Feels Like | |------------|-------------------| | SVT (Supraventricular Tachycardia) | Sudden racing (150-250 bpm), starts and stops abruptly | | Atrial Fibrillation | Irregular, fluttering, may come and go | | Premature Beats (PVCs/PACs) | Skipped beats, flip-flops, thumping |

• Fever or Infection
• Heart rate increases about 10 bpm per degree Fahrenheit
• Body fighting infection requires more circulation
• Resolves when illness clears

1. Manual: Place two fingers on inner wrist, count beats for 15 seconds, multiply by 4
2. Fitness tracker: Most give continuous readings
3. Smartphone app: Many can detect pulse through camera
4. Blood pressure cuff: Many include heart rate

• Schedule an appointment if:
• Racing heart happens frequently
• Episodes are getting worse or longer
• You have risk factors for heart disease
• It's affecting your quality of life
• You haven't had it evaluated before
• You have symptoms of thyroid problems or anemia

1. ECG/EKG: Records heart's electrical activity
2. Blood tests: Thyroid, anemia, electrolytes
3. Holter monitor: 24-48 hour continuous heart recording
4. Event monitor: Wear for weeks, press button when symptoms occur
5. Echocardiogram: Ultrasound of heart structure (if needed)

• Limit caffeine (or eliminate for 2 weeks to see effect)
• Stay well hydrated
• Get regular, adequate sleep
• Manage stress ([anxiety treatment](/condition/anxiety) if needed)
• Exercise regularly (strengthens heart, reduces resting rate)
• Limit alcohol
• Avoid smoking and nicotine