Why do I feel heart palpitations and anxiety the moment I lie down to sleep?

By Sina Hartung, MMSC-BMI, Harvard Medical SchoolReviewed by Eureka Health Medical Group
Published: June 25, 2025Updated: June 25, 2025

Summary

Sudden pounding in the chest, racing thoughts, and an inability to fall asleep often stem from a surge of nighttime sympathetic (“fight-or-flight”) activity. Lying flat can accentuate awareness of your heartbeat, while anxiety and caffeine, thyroid overactivity, or an irregular rhythm like premature atrial contractions may worsen sensations. Most cases are benign, but persistent or escalating palpitations demand medical review, ECG monitoring, and targeted stress-reduction techniques.

Could nighttime palpitations and insomnia simply be an anxiety surge?

Yes—about 60 % of people who report palpitations in sleep studies have no structural heart disease; heightened anxiety and increased adrenaline are the main drivers. When you lie flat, there are fewer external distractions, so you notice each heartbeat more. Yet it is essential to rule out medical causes before attributing everything to stress.

  • Fight-or-flight hormones peak as you unwindCatecholamine levels can remain 30 % higher in stressed individuals, making the heartbeat feel forceful once external noise drops.
  • Awareness of your own pulse increases in silenceWithout daytime sounds, even normal premature beats (up to 150 per day is common) become noticeable.
  • Breathing pattern shifts can trigger palpitationsShallow chest breathing during anxiety lowers carbon dioxide, which can induce tingling and a racing heart.
  • Expert insight“Most people mistake a normal sinus tachycardia for a dangerous arrhythmia. We first exclude cardiac disease, then tackle stressors,” says the team at Eureka Health.
  • Stress and insomnia raise atrial fibrillation risk in womenA cohort study following 83,000 post-menopausal women showed that roughly 25 % developed atrial fibrillation, with higher stress and insomnia scores independently increasing risk—highlighting why nocturnal palpitations merit a cardiac evaluation before being labeled as ‘just anxiety’. (HRI)
  • Poor sleep amplifies cardiovascular sensations in anxious peopleCardiology research found that individuals with high anxiety who also suffered insomnia reported markedly more palpitations and chest discomfort than anxious good sleepers, indicating that wakefulness at night magnifies adrenaline-driven heart sensations. (NCBI)

References

When are nighttime palpitations a red flag that needs urgent care?

While occasional flutters are often benign, certain warning signs suggest a potentially serious arrhythmia or cardiac disorder. Immediate assessment can be lifesaving.

  • Sustained heart rate above 120 beats/min at restA rate that stays over 120 for more than 15 minutes may signal supraventricular tachycardia or atrial fibrillation.
  • Chest pressure, fainting, or near-syncopePalpitations plus dizziness or shortness of breath triple the odds of a cardiac cause versus anxiety alone.
  • Palpitations waking you after falling asleepNocturnal episodes associated with gasping can indicate sleep apnea-related atrial fibrillation.
  • Quote from our expert“If palpitations are paired with blackouts, call emergency services—do not wait for a morning clinic,” advises Sina Hartung, MMSC-BMI.
  • Resting pulse below 45 beats/min warrants emergency evaluationVerywell Health advises calling 911 if nighttime palpitations accompany a heart rate under 45 bpm, as severe bradycardia can signal conduction disturbances or advanced cardiac disease. (VWH)
  • Exercise-induced palpitations or a family history of sudden death require urgent assessmentPalpitations that start during physical exertion, or occur in individuals with a personal or family history of fainting or sudden cardiac death, are considered high-risk and should be evaluated in an emergency setting. (VWH)

References

Could something other than anxiety be causing the pounding in my chest?

Several physical conditions mimic anxiety-induced palpitations. A focused evaluation helps distinguish them.

  • Thyroid overactivity accelerates nighttime heart rateHyperthyroidism raises resting pulse by 10–20 beats/min; a TSH below 0.4 mIU/L warrants testing.
  • Iron-deficiency anemia forces the heart to work harderHemoglobin under 11 g/dL can double cardiac output during sleep, creating a thumping sensation.
  • Premature atrial or ventricular contractions are commonUp to 1 in 4 healthy adults have benign ectopic beats, which feel like skips followed by a heavy beat.
  • Caffeine and alcohol late in the day prolong alertnessA double espresso after 3 pm can delay melatonin release by 40 minutes and trigger extra beats.
  • Expert reflection“Identifying a reversible trigger—like a 10-minute bedtime doom-scroll—often solves half the problem,” notes the team at Eureka Health.
  • Insomnia and life stress raise atrial fibrillation risk after menopauseIn a cohort of more than 83,000 post-menopausal women followed for a decade, about 25 % developed atrial fibrillation; those with the highest insomnia scores and stressful life events faced the greatest risk, showing that poor sleep can trigger palpitations independent of anxiety. (HRI)
  • Even mild dehydration can drop blood pressure and provoke palpitationsCardiovascular specialists note that reduced plasma volume forces the heart to beat harder when fluid levels are low, making fluttering or pounding in the chest a common early sign of dehydration that warrants checking electrolytes. (CVC)

References

What self-care steps calm palpitations so I can finally sleep?

Targeted lifestyle tweaks often relieve both the heartbeat sensation and the insomnia. Implement them consistently for at least two weeks.

  • Practice physiologic sigh breathing for 5 minutesInhaling twice then exhaling slowly lowers heart rate variability within 120 seconds, according to Stanford sleep data.
  • Keep bedroom temperature between 60–67 °FCool surroundings encourage parasympathetic dominance, lowering resting pulse by roughly 4 beats/min.
  • Limit screens one hour before bedBlue-light exposure at 10 pm suppresses melatonin up to 23 %, maintaining alertness and a faster pulse.
  • Use the Valsalva maneuver when a flutter startsBearing down for 10–15 seconds can break some supraventricular tachycardias under medical guidance.
  • Expert tip“Write a quick ‘worry list’ then park it outside the bedroom—it externalizes racing thoughts,” suggests Sina Hartung, MMSC-BMI.
  • Splash cold water on your face to spark the diving reflexHolding your breath while briefly dousing your face can stimulate the vagus nerve and slow a racing heartbeat within about 30 seconds. (Healthgrades)
  • Meet daily fluid goals to curb dehydration-triggered fluttersIsland Hospital advises roughly 15.5 cups of water a day for men and 11.5 cups for women—shortfalls can precipitate nighttime palpitations. (IslandHosp)

References

Which tests and treatments should I discuss with my clinician?

A concise work-up rules out disease and guides therapy without over-testing. Share a clear symptom diary—time, pulse, triggers—with your provider.

  • 12-lead ECG and possibly a 24-hour Holter monitorThese detect arrhythmias like atrial fibrillation that casual blood-pressure cuffs can miss.
  • TSH, free T4, and iron panelAbnormal thyroid or ferritin levels explain up to 15 % of unexplained palpitations in primary-care cohorts.
  • Beta-blockers or low-dose calcium-channel blockers may be offeredDoctors sometimes prescribe these to blunt excessive adrenergic response; dose is individualized.
  • Occasional short-acting sleep aids can break a vicious cycleDiscuss options such as low-dose doxepin; benefits must outweigh next-day grogginess.
  • Expert reassurance“Most patients improve with targeted lifestyle changes plus a short monitoring period,” reports the team at Eureka Health.
  • 30-day event recorders capture elusive rhythm problemsMayo Clinic notes that patient-activated event monitors can be worn for up to 30 days, providing a better chance of catching infrequent arrhythmias than a 24-hour Holter. (Mayo Clinic)
  • Anxiety and panic disorder explain a large share of palpitationsReview data summarized by AAFP show 31 % of palpitation cases stem from anxiety or panic disorder, compared with 43 % caused by cardiac arrhythmias, highlighting the need to screen mental health. (AAFP)

References

How can Eureka’s AI doctor guide me through nighttime palpitations?

Eureka’s AI doctor collects your symptom pattern, suggests appropriate tests, and flags emergencies. The tool mirrors the clinical reasoning of board-certified physicians.

  • Symptom triage in under two minutesYou answer structured questions; the AI assigns a risk tier using guidelines from the American Heart Association.
  • Personalized testing recommendationsIf your answers suggest hyperthyroidism, it proposes TSH and free T4, which a physician reviewer can approve.
  • Medication review and interaction checkUpload your current list—Eureka cross-checks for stimulants that might worsen palpitations.
  • Statistic that builds trustUsers with sleep issues rate Eureka’s insomnia pathway 4.7 out of 5 for clarity.
  • Quote on usefulness“Patients feel heard because the AI never rushes them and turns their narrative into a structured plan,” says Sina Hartung, MMSC-BMI.

Why use Eureka’s AI doctor instead of scrolling forums at 2 am?

Forums can be reassuring but often spread myths. Eureka combines evidence-based guidance with real clinicians’ oversight, all while respecting your privacy.

  • 24/7 access without appointment backlogsUnlike clinics that book weeks out, Eureka answers questions instantly—crucial when anxiety peaks at bedtime.
  • Data stays encrypted and under your controlHIPAA-grade encryption safeguards entries; you decide if and when to share reports with your doctor.
  • Long-term tracking of palpitations and sleepDaily check-ins create a trend graph, helping you see if cutting caffeine actually lowered nighttime pulse.
  • Physician review for prescriptionsIf the AI flags a need for beta-blocker renewal, a licensed doctor confirms safety before sending it to your pharmacy.
  • User endorsement“Knowing an evidence-based plan is a tap away lets me fall asleep faster,” one beta tester told the team at Eureka Health.

Become your own doctor

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Frequently Asked Questions

Can lying on my left side cause palpitations?

Yes, the heart sits closer to the chest wall on the left. This position can amplify awareness but usually does not cause an actual arrhythmia.

How many skipped beats per day are considered normal?

Up to 150 premature beats in 24 hours is generally considered benign if you have no structural heart disease.

Should I buy a smartwatch for overnight pulse tracking?

Consumer devices are helpful trend tools, but any reading that concerns you—especially irregular rhythms—should be verified with medical-grade ECG.

Does magnesium really calm palpitations?

Only if you are deficient. Blood magnesium below 1.7 mg/dL can contribute to palpitations; supplements beyond that level show little added benefit.

Can dehydration in summer worsen nighttime heart pounding?

Yes, low plasma volume makes the heart beat faster to maintain blood pressure. Aim for clear urine and a 0.5–1 lb overnight weight loss threshold.

Is it dangerous to exercise if I get palpitations at night?

Moderate daytime exercise actually reduces nighttime sympathetic tone. Stop only if you experience chest pain, dizziness, or a rapid irregular rhythm.

Do antihistamines like diphenhydramine cause heart racing?

They can. First-generation antihistamines have anticholinergic effects that may increase heart rate in sensitive individuals.

How long should I try lifestyle changes before seeking help?

If symptoms persist beyond two weeks despite good sleep hygiene—or sooner if red-flag signs appear—book a medical review.

Can menopause trigger these night palpitations?

Yes, estrogen fluctuations alter autonomic balance, and up to 50 % of perimenopausal women report nocturnal heart racing.

Will cutting out all caffeine fix the problem?

It helps many people, but not all. Track your intake and symptoms; a two-week caffeine-free trial is the simplest test.

This content is for informational purposes only and is not intended as medical advice. Always consult with a qualified healthcare provider for diagnosis, treatment, and personalized medical recommendations.

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