Heartburn at night: why it gets worse lying down
Reflux often feels worst the moment your head hits the pillow. Here's why nighttime is harder on a refluxy gut — and the practical changes that help you sleep through it.
Nighttime is when reflux loses its best ally: gravity.
Plenty of people get through the day fine and then dread bedtime. You lie down, and within minutes there's that familiar burn rising behind the breastbone, maybe a sour taste at the back of the throat, sometimes a cough that won't settle. Nighttime heartburn is one of the most common — and most disruptive — faces of acid reflux, and it isn't your imagination that it's worse after dark. The body simply manages reflux less well when you're flat and asleep.
Why reflux gets worse when you lie down
Several things that protect you during the day quietly switch off at night. Together they explain why a problem that's mild at your desk can flare the moment you go horizontal.
- You lose gravity. Upright, gravity helps keep stomach contents where they belong. Lying flat removes that help, so acid can travel back up the esophagus far more easily.
- You swallow and salivate less. Swallowing and saliva are how the esophagus normally clears acid and neutralises it. Both drop sharply during sleep, so whatever refluxes up sits there longer instead of being washed back down.
- Dinner is still digesting. A large or late meal means a full, working stomach right when you lie down — more volume and pressure pushing upward.
- The valve can relax. The lower esophageal sphincter (LES), the muscular valve at the top of the stomach, can loosen — and certain late-evening foods and drinks make that more likely.
The combination matters: acid comes up more easily and stays up longer. That's why nighttime reflux is linked to poorer, more broken sleep, and why it tends to irritate the esophagus more — the acid simply lingers in contact with the lining instead of being cleared in a swallow or two.
Daytime reflux gets washed away in seconds by swallowing and gravity. At night both of those defences are offline, so the same splash of acid sits and stings for much longer.
How to sleep through it
The good news is that nighttime reflux responds well to a handful of practical changes. None of them are dramatic, and they stack — doing several together works better than any single one.
Find what's driving your night flare-ups
Nighttime reflux almost always traces back to the evening — what you ate, how much, and how late. Because the symptoms arrive hours after the meal, the link is easy to miss in the moment. The dependable way to see it is to log your evening meals and your nighttime symptoms for a couple of weeks and look for the foods and habits that repeatedly show up before a bad night.
When to see a doctor
Occasional nighttime heartburn that responds to these changes is usually nothing to worry about. See a clinician if:
- Heartburn wakes you two or more nights a week, or persists despite the changes above.
- You wake up choking or coughing, or with a sour taste, on a regular basis.
- You have trouble swallowing, or food feels like it sticks.
- You have chest pain — this always needs to be checked to rule out a cardiac cause, not assumed to be reflux.
The bottom line
Nighttime heartburn is worse because lying flat takes away gravity and sleep takes away swallowing — the two defences that keep daytime reflux in check. Time your last meal earlier, keep it lighter, raise the head of the bed, and favour your left side, and most people sleep far better. To pin down which evening foods set off your nights, see how to find your personal reflux triggers or the GERD diet: what to eat and avoid.
Key facts
- Why worse at night
- No gravity + less swallowing to clear acid
- Eat by
- About 3 hours before bed
- Bed angle
- Raise the head 6–8 inches
- Best side
- Left
- Red flag
- Frequent night symptoms → see a doctor
FAQ
Why is my acid reflux worse at night?+
Lying flat removes the gravity that normally keeps stomach contents down, so acid flows back up the esophagus more easily. During sleep you also swallow less and produce less saliva — the two things that usually clear acid — so anything that comes up lingers longer. A large or late dinner that's still digesting adds to the load.
What side should I sleep on for acid reflux?+
The left side tends to help. Because of where the stomach sits, lying on the left keeps the junction between stomach and esophagus above the pool of stomach contents, so there's less reflux. The right side, or flat on your back, is generally worse for nighttime heartburn.
Does raising the head of the bed help heartburn?+
Yes — raising the head about 6 to 8 inches lets gravity keep acid down overnight. Use bed risers under the head legs or a wedge that lifts your whole upper body. Stacking extra pillows usually doesn't help; it bends you at the waist and can raise abdominal pressure, making reflux worse.