Waking Up With a Racing Heart at Night: Causes and What to Do

You jolt awake in the dark. Your heart is pounding so hard you can feel it in your throat, your mind is suddenly sharp, and for a moment you are not sure what woke you. Maybe it settles in a minute or two. Maybe you lie there for an hour, listening to your pulse and wondering whether something is wrong.

Waking up with a racing heart is unsettling, and it is also very common. Most of the time it comes from things that are understandable and fixable: stress hormones, a vivid dream, alcohol, a late meal, or a body that is a little out of balance. Sometimes, though, it can point to a heart rhythm issue, a breathing problem during sleep, or another medical condition that deserves a proper check. This guide walks through the most common causes, what you can do in the moment, how to reduce the chance of it happening again, and when it is time to see a doctor.

What Is Happening in Your Body

Your heart rate naturally slows during sleep, especially in deeper stages. It also varies. During REM sleep, the stage linked with vivid dreaming, heart rate and breathing can become more irregular and speed up for short bursts. That is normal.

A racing heart on waking usually means your body has switched into "fight or flight" mode. Your nervous system releases adrenaline and related hormones, which raise your heart rate, sharpen your senses, and make you feel suddenly alert. The question is what flipped that switch.

It also helps to know that the feeling of your heartbeat is more noticeable at night. When the room is quiet and you are lying still, especially on your left side, you may notice heartbeats you would never feel during a busy day. That awareness alone can kick off a worried loop: you notice your heart, you feel anxious, your heart speeds up, and you notice it even more.

Common Causes of Waking Up With a Racing Heart

Stress and anxiety

Ongoing stress keeps your nervous system on a higher setting, even while you sleep. Many people with anxiety find that the night is when it breaks through, because there are no distractions. Nocturnal panic attacks, which wake you from sleep with a pounding heart, shaking, sweating, or a sense of dread, are a recognized pattern. They are frightening but not dangerous in themselves. Our article on anxiety and insomnia explains how the two feed each other.

Nightmares and vivid dreams

A frightening dream can trigger a real stress response. Your body reacts as though the threat were happening, and you wake with your heart racing before you have even remembered the dream. If this happens often, see what vivid dreams say about your sleep.

Alcohol

Alcohol is a common and often overlooked cause. It may help you doze off, but as your body processes it in the second half of the night, it can cause a rebound in alertness, faster heart rate, sweating, and lighter, more broken sleep. Holiday season parties make this especially relevant in November and December. We explain the full effect in alcohol and sleep: the honest truth.

Caffeine, nicotine, and other stimulants

Caffeine can stay active in your system for many hours. Nicotine, some decongestants, certain asthma inhalers, thyroid medication doses that are too high, and some weight loss or energy products can also raise heart rate. If you started a new medication recently, ask your pharmacist whether it can affect your heart rate or sleep.

Blood sugar dips

For some people, especially those with diabetes or who eat a large sugary meal or drink alcohol late, blood sugar can drop overnight. Your body responds by releasing stress hormones to bring it back up, which can wake you with a racing heart, sweating, or shakiness. Our guide to blood sugar and sleep covers this in more detail.

Sleep apnea and breathing pauses

In obstructive sleep apnea, your airway partly or fully closes repeatedly during sleep. Each time oxygen drops, your body jolts you toward waking to restart breathing, often with a surge in heart rate. You might wake gasping or choking, or you may not remember waking at all. Loud snoring, morning headaches, and heavy daytime sleepiness are common clues. Read more in snoring vs sleep apnea.

Hormonal changes

Shifts in hormones can bring on night sweats and a pounding heart. This is very common during perimenopause and menopause, and can also happen around the menstrual cycle and during pregnancy. An overactive thyroid can cause a fast heart rate day and night. If you suspect hormones are involved, our articles on hot flashes at night and thyroid and sleep are good next reads.

Dehydration, fever, or illness

Being dehydrated or running a fever makes your heart work harder. A racing heart during a cold, flu, or other infection is often part of your body fighting it off.

Heart rhythm problems

Some people have palpitations because of an arrhythmia, a problem with the heart's electrical rhythm. Examples include extra beats (which feel like a skip or thud), episodes of a fast regular rhythm that start and stop suddenly, or atrial fibrillation, which often feels fast and irregular. These are not something to diagnose at home. If your racing heart feels irregular, comes with other symptoms, or keeps happening, it is worth a medical check.

What to Do in the Moment

If you wake with a racing heart and you do not have any warning signs (see the doctor section below), these steps can help your body settle.

1. Pause and name it. Tell yourself, "My heart is racing because my stress system switched on. This feeling is uncomfortable, and it will pass." Naming it helps reduce the fear that adds fuel.
2. Slow your breathing. Breathe in gently through your nose for a count of four, and out slowly for a count of six or more. Long exhales activate the calming side of your nervous system. Box breathing is another simple pattern.
3. Change position. If you are lying on your left side, roll onto your back or right side. This can make your heartbeat less noticeable.
4. Cool down. Push off heavy covers, sip some water, and if you are hot, splash cool water on your face or wrists.
5. Relax your muscles. Starting from your feet, tense each muscle group for a few seconds, then let it go. Work your way up to your face.
6. Get up if you cannot settle. If you are still wide awake after what feels like 20 minutes, go to another dim room and do something calm until you feel sleepy again. Lying in bed checking your pulse tends to keep the alarm going. Our guide to falling back asleep after waking has more ideas.

Try not to check your phone or a smartwatch repeatedly. Watching numbers in the middle of the night often increases anxiety rather than reducing it.

How to Reduce Night-Time Heart Racing

Prevention usually comes down to calming your system during the day and evening.

• Limit alcohol, especially within a few hours of bed. If you notice a pattern after drinks, that is useful information.
• Set a caffeine cutoff in the early afternoon, and check labels on energy drinks, pre-workout products, and some pain relievers.
• Eat balanced evening meals. Combine protein, fiber, and healthy fats rather than a large sugary dessert or drinks late at night.
• Build a wind-down routine. Dim lights, set aside work, and give your mind time to slow down before you lie down.
• Deal with worries earlier. A short evening "worry list" can stop the same thoughts from showing up at 3 a.m.
• Move your body regularly. Regular exercise tends to lower resting heart rate and improve sleep, though very intense workouts close to bedtime can keep some people wired.
• Stay hydrated through the day so you are not short on fluids overnight.
• Keep a short log. Note the time, what you ate and drank, stress level, and any symptoms. Patterns often appear within a couple of weeks and are helpful to share with a doctor.

If anxiety is the main driver, approaches like cognitive behavioral therapy (CBT) and CBT-I for insomnia have strong evidence for reducing both night-time anxiety and broken sleep.

When to See a Doctor

Call emergency services right away if a racing heart comes with any of these:

• Chest pain, pressure, or tightness, or pain spreading to your arm, jaw, neck, or back
• Severe shortness of breath
• Fainting, nearly fainting, or sudden confusion
• A very fast heart rate that does not settle with rest
• Sudden weakness, numbness, trouble speaking, or a drooping face

Make a non-urgent appointment with your doctor if:

• You wake with a racing or pounding heart more than occasionally, or it is getting more frequent
• Your heartbeat feels irregular, fluttering, or like it is skipping beats often
• You snore loudly, gasp or choke in your sleep, or feel very sleepy during the day
• You have night sweats, unexplained weight changes, or feel hot and shaky often
• You have a known heart condition, diabetes, thyroid disease, or high blood pressure
• You recently started a new medication or supplement
• Anxiety or panic is affecting your sleep and daily life

A doctor may check your blood pressure, run blood tests, and arrange a heart rhythm recording or a sleep study. Many causes are very treatable once identified.

If you want a clearer picture of how stress, habits, and your body clock are shaping your nights, take our free 2-minute sleep quiz for a personal starting point.

The Bottom Line

Waking up with a racing heart is frightening, but it is usually your body's stress response doing its job a little too eagerly, often triggered by anxiety, dreams, alcohol, stimulants, blood sugar swings, or hormones. Slow breathing, a cooler room, and getting up when you cannot settle can help in the moment, while calmer evenings and fewer late stimulants can reduce how often it happens. If it comes with chest pain, breathlessness, or fainting, or if it keeps happening, get it checked. Peace of mind is worth the appointment.

This article is educational, not medical advice. Call emergency services immediately if a racing heart comes with chest pain, severe shortness of breath, fainting, confusion, or signs of a stroke. See a doctor if night-time palpitations are frequent or irregular, if you snore loudly or gasp in your sleep, or if you have a known heart, thyroid, or blood sugar condition.