Waking up with heart palpitations, skipped beats, fluttering, or a hard pounding rather than a sustained fast racing feeling, can mean your body triggered a sudden “alert” response during sleep, for example from stress hormones, blood sugar changes, or breathing disruptions. It can feel alarming, but the NHS says palpitations are common and not usually a sign of anything serious. If your heart feels like it’s simply racing fast rather than skipping or pounding irregularly, see why you wake up with a racing heart instead; for the hormone side, see can cortisol wake you up at night. Palpitations are usually harmless, but some need a doctor’s check, so read when to get them checked.
Who this is for
- You wake up suddenly with a fast or pounding heartbeat
- It happens in the middle of the night or early morning
- Your heart settles after a few minutes
- You sometimes feel anxious, shaky, or sweaty when it happens
- It happens occasionally or in patterns
Quick Fix / Summary
- Focus on slow breathing when it happens
- Avoid alcohol and sugar before bed
- If you suspect a blood sugar dip, ask your doctor before changing evening eating, especially if you have diabetes
- Improve your breathing (reduce mouth breathing/snoring)
- Keep your room cool and comfortable
- Track timing and triggers
What’s Actually Causing Nighttime Heart Palpitations
1. Adrenaline From a Stress Response
Adrenaline, the hormone behind the body’s fight-or-flight response, makes your heart beat faster (Cleveland Clinic), so a stress-driven wake-up can be felt in the chest first. Mayo Clinic lists strong emotional responses such as stress, anxiety or panic attacks among the common causes of palpitations, and the NHS lists stress and anxiety too (see when to get palpitations checked).
If the pounding arrives with dread or a racing mind, waking up with anxiety in the middle of the night covers how to calm it in the moment; for what cortisol actually does overnight, see how cortisol can wake you at night.
2. A Blood Sugar Dip (Less Common Without Diabetes)
A fast or unsteady heartbeat, sweating and shakiness are classic signs of low blood sugar, because the body releases adrenaline to bring it back up. That is well documented in people with diabetes, especially those on insulin or certain diabetes medicines (NIDDK); in people without diabetes, true overnight lows are much less common, so test it rather than assume it. Why you wake up at 3am every night has a simple food-timing test, and does blood sugar affect sleep at night covers the mechanism.
3. Breathing Disruptions During Sleep
When breathing stalls or becomes unstable during sleep, the body can jolt you awake with your heart pounding. Loud snoring, waking up gasping, or feeling unrefreshed after a full night are worth taking seriously because they can point to sleep apnea; why you wake up gasping for air at night explains the signs and when to see a doctor.
4. You’re Waking From a Light Sleep Stage
Toward morning, your sleep becomes lighter.
What this means:
- You’re easier to wake
- Your body reacts more strongly to small changes
Result:
You may wake up suddenly with a noticeable heartbeat.
5. Overheating Can Trigger a Wake-Up Response
Heat can push your body into lighter sleep and trigger sudden awakenings.
What this looks like:
- You wake up warm or sweaty
- Your heart feels more noticeable
What to do:
- Use breathable bedding
- Keep your room slightly cool
- Improve airflow
If this happens often, improving how you sleep cooler at night can help stabilize your sleep.
6. Alcohol or Late Habits Disrupt Your Sleep
Certain habits increase nighttime instability.
What happens:
- Alcohol disrupts sleep cycles
- A large sugary snack right before bed may leave some people’s sleep less settled
Result:
Your body becomes more reactive during the night.
What to do:
- Avoid alcohol before bed
- Eat lighter, balanced meals earlier
What To Do When It Happens
Step-by-step:
- Stay calm
The sensation is uncomfortable but usually temporary - Focus on slow breathing
- Inhale 4 seconds
- Exhale 6–8 seconds
- Stay still or sit up slowly
Let your body settle - Avoid checking the time
Reduces stress and alertness - Let it pass naturally
Episodes can last seconds, minutes or longer, so note how long it lasts
When to Get Palpitations Checked
The NHS notes that palpitations are common and not usually a sign of anything serious. Common triggers include stress and anxiety, lack of sleep, alcohol, caffeine, nicotine and some medicines. Still, it is worth seeing a doctor if:
- They keep coming back or are happening more often
- They last longer than a few minutes
- You have a heart condition, or heart problems run in your family
Get emergency help (999 or 911) if palpitations come with chest pain, shortness of breath, or feeling faint or fainting. If they do not settle, get urgent medical advice (NHS 111 in the UK).
How to Reduce These Episodes Long-Term
- Keep evenings calm and low-stimulation
- Avoid sugar and alcohol late
- Improve breathing and sleep position
- Maintain a consistent sleep schedule
- Track patterns to identify triggers
Practical Tips That Actually Help
- If it happens at the same time → look at cortisol or blood sugar
- If you feel anxious → calm your body first
- If you wake up dry → breathing may be involved
- If it follows certain habits → adjust your evenings
- Steadier evenings may help over a week or two, but keep a note of how often it happens
Common Mistakes to Avoid
- Panicking during the episode – can keep your body on alert
- Checking the time repeatedly
- Using your phone after waking
- Ignoring patterns in timing or triggers
- Relying on quick fixes without changing habits
Frequently Asked Questions
Are heart palpitations at night dangerous?
Usually not. The NHS says palpitations are common and not usually a sign of anything serious, and that they can last seconds, minutes or longer. See a doctor if they keep coming back, last longer than a few minutes, or you have a heart condition, and get emergency help if they come with chest pain, shortness of breath or fainting.
What’s the difference between heart palpitations and a racing heart at night?
Palpitations usually feel like skipped beats, fluttering, or hard pounding, rather than a sustained fast racing feeling. If your heart feels like it’s simply racing fast, that’s covered separately since the pattern and triggers differ slightly.
What should I do in the moment when my heart starts pounding at night?
Stay calm, since the sensation is uncomfortable but usually temporary. Use slow breathing, inhaling for 4 seconds and exhaling for 6-8 seconds, stay still or sit up slowly, and avoid checking the time, which only adds stress and alertness.
Can what I eat or drink before bed cause this?
Alcohol can. The NHS lists it among common palpitation triggers, and it also disrupts sleep later in the night. Sugar is less clear-cut: a large sugary snack before bed may unsettle sleep for some people, but in people without diabetes true overnight blood sugar lows are uncommon, so treat it as something to test.
How long does it usually take for these episodes to improve?
If they are linked to evening habits or stress, steadier evenings often make them less frequent over a week or two. If they keep coming back, last more than a few minutes, or you have a heart condition, see a doctor.
Key Takeaways
Waking up with heart palpitations is often caused by stress responses, blood sugar changes, or breathing disruptions during sleep. Steadier evening habits often make them less frequent, but palpitations that keep coming back, last more than a few minutes, or come with chest pain, breathlessness or fainting need a doctor. For the fuller physiological picture of how cortisol and adrenaline drive this, see can cortisol wake you up at night.
Related Reading
- Can Cortisol Wake You Up at Night?
- Why Do I Wake Up at Night With a Racing Heart?
- Why Do I Wake Up With Anxiety in the Middle of the Night?
About this article
Written by the Sleep Fixes editorial team. We’re not medical professionals. We research each topic against primary sources and hold ourselves to being critical and thorough about what actually makes it onto the site.
This article is part of Sleep Fixes, a site focused on practical, easy-to-follow solutions for common sleep problems like night waking, dry mouth, overheating, and disrupted sleep.
The content is based on widely accepted sleep principles and common real-world patterns, with a focus on simple changes that may improve sleep quality.
It is not medical advice. If your symptoms are severe, persistent, or worsening, consider consulting a qualified healthcare professional.