Definition
Heart palpitations are an awareness of the heart beating in a way that feels unusual, whether faster, harder, irregular, or simply more noticeable than usual. Most palpitations in healthy adults are benign, but new, frequent, or sustained palpitations warrant cardiac evaluation, particularly when accompanied by chest pain, fainting, or shortness of breath.
What it can feel like
A pounding or fluttering in the chest. A skipped beat followed by a stronger beat. A sudden awareness of the heartbeat in quiet moments, especially at night when other sensory input is low. The experience can be brief or sustained, and it tends to feel more alarming the more attention is paid to it.
Why it happens
Adrenaline raises both heart rate and the force of contraction, which makes individual beats more perceptible. Caffeine, alcohol, sleep loss, dehydration, and certain medications also amplify the sensation. Once an evaluation has ruled out cardiac causes, palpitations are often part of the broader picture of anxiety, where the original sensation triggers monitoring, the monitoring triggers more activation, and the cycle reinforces itself. Treatment is typically the underlying anxiety pattern rather than the heart.
What palpitations actually feel like
Patients describe palpitations in several distinct ways, and the description is clinically meaningful. A pounding heartbeat that's hard to ignore, often more noticeable when lying down, is usually increased force of contraction during sympathetic activation, the most common pattern in anxiety. A skipped or flipped beat followed by a more forceful beat is usually a premature atrial or ventricular contraction; most adults have a small number daily without noticing. A run of fast, regular beats that starts and stops abruptly can suggest a supraventricular tachycardia, benign in most cases but worth a workup if recurring. A racing irregular beat in someone over 40 or with cardiac risk factors warrants evaluation for atrial fibrillation; this pattern isn't typical of anxiety.
Knowing which pattern is happening is part of what a clinical evaluation is for. An EKG and, in some cases, an event monitor (a small wearable device that captures the rhythm during a symptomatic episode) usually clarify the picture quickly.
Why caffeine matters more than people expect
Caffeine is the most underrated driver of palpitations in adults presenting with anxiety. Two reasons. Caffeine sensitivity varies widely by genetics, the CYP1A2 enzyme has fast and slow variants, and a slow metabolizer who drinks the same amount as a friend will have substantially higher and longer-lasting circulating caffeine. Cumulative dose adds up quickly: a morning coffee, a mid-morning second cup, a soda, a pre-workout supplement, and a late-afternoon tea can easily reach 600 to 800 mg, far above the 400 mg threshold most adults tolerate without effects.
A two-week experiment usually clarifies the role. Reducing total caffeine to under 200 mg daily often halves the symptom in patients whose palpitations had been attributed entirely to anxiety.
Sleep, hydration, and the small things that compound
Two other commonly missed contributors. Dehydration concentrates blood volume and increases heart rate; many patients turn out to be drinking far less water than they think, and a target of roughly 2 liters daily often makes a noticeable difference. Short sleep reliably increases ectopic beats, the night after four hours of sleep, the next day's PAC rate climbs measurably. Combined with caffeine to compensate for the fatigue, the effect compounds. Protecting sleep is one of the most effective non-medication interventions for recurring anxiety palpitations.
When to see a clinician
A first episode of unexplained palpitations should be evaluated medically, including an EKG. Once cardiac causes have been ruled out, recurring anxiety-driven palpitations usually respond well to treatment of the underlying anxiety, often paired with caffeine reduction.