Acid reflux at night: why it happens and what helps

Acid reflux is often worse at night because lying down takes away gravity, and sleep slows the things that normally clear acid from your esophagus. During the day, three things work in your favor:

• Gravity. When you sit or stand, your stomach sits below your esophagus, so acid has to work against gravity to rise. Lying flat puts them on the same level.
• Swallowing. Each swallow pushes acid back down. You swallow far less often while asleep.
• Saliva. Saliva is mildly alkaline and helps neutralize acid. Your mouth makes much less of it during sleep.

So acid that would be cleared in seconds during the day can sit in the esophagus for longer at night. That is why night reflux can feel stronger and linger, and why it can wake you up.

The most common causes of night reflux are eating too close to bed, eating a large or rich dinner, and lying flat. They often stack on top of each other.

• A late dinner. A stomach that is still full when you lie down has more to push back up. Many clinicians suggest finishing your last meal two to three hours before bed.
• A big or fatty meal. Large portions and fat slow how fast the stomach empties, so food and acid are still there at bedtime.
• Evening drinks. Alcohol, coffee, and fizzy drinks after dinner can relax the valve at the top of the stomach (the lower esophageal sphincter) or add pressure.
• Your own trigger foods. Tomato sauce, chocolate, peppermint, spicy food, and others bother many people. See our guide to GERD trigger foods for the full list and why each one matters.
• Pressure on the stomach. Tight waistbands and extra weight around the middle push up on the stomach, especially when lying down.

The changes with the most support are eating earlier, raising the head of your bed, and avoiding the foods that set you off. These are the steps most clinicians suggest first:

• Leave two to three hours between dinner and bed. If your evenings are busy, try moving the larger meal to lunch and keeping dinner lighter.
• Raise the head of your bed. Blocks under the bed's head legs or a wedge under the mattress lift your whole upper body. Stacking pillows tends to bend you at the waist, which can squeeze the stomach instead.
• Try sleeping on your left side. Some small studies have found less night reflux on the left side than the right, likely because the stomach then sits below the esophagus. The evidence is limited, but it costs nothing to try.
• Keep late snacks small and plain, if you need one at all.
• Loosen up at night. Change out of anything tight around your waist before you settle in.

If you smoke, stopping helps reflux too. Smoking weakens the valve and reduces saliva.

Night reflux usually shows up as heartburn when you lie down, or as signs you notice the next morning. Common ones include:

• A burning feeling in the chest or throat after lying down
• Waking with a sour or bitter taste in your mouth
• A cough or throat clearing that gets worse at night
• A hoarse voice or sore throat in the morning
• Waking up coughing or with fluid in your throat
• Broken sleep without an obvious reason

Some people have little daytime heartburn at all, so night signs like a morning cough can be easy to miss as reflux.

The clearest way to find your cause is a two-week experiment: log when you eat dinner, what it was, when you go to bed, and how you slept. General advice can't tell you which habit matters most for you, but your own log can.

1. Week one, change nothing. Log dinner time, the main foods and drinks, bedtime, and any night symptoms with a 1 to 10 rating.
2. Look at the gap. Compare nights where dinner ended three or more hours before bed with nights where it didn't.
3. Week two, change one thing. Pick the most likely culprit (the late meal, the glass of wine, the tomato sauce) and change only that. Changing everything at once hides which step helped.
4. Compare the two weeks. Fewer bad nights after one change is a strong clue.

Our guide to keeping a food and symptom diary covers what else is worth logging and how to read the results.

Why do I only get acid reflux at night?

Lying down removes gravity, and you swallow less and make less saliva while asleep, so small amounts of reflux you would not notice during the day can cause symptoms at night. A late or large dinner makes this more likely.

Which side should I sleep on for acid reflux?

Your left side. Small studies suggest less night reflux in that position than on the right side or flat on your back, though the evidence is limited.

Does drinking water help acid reflux at night?

A few sips of water can rinse acid from the esophagus and may ease mild heartburn briefly. Drinking a lot right before bed fills the stomach, which can make reflux more likely.

Can acid reflux cause a cough at night?

Yes. Acid reaching the throat can trigger coughing and throat clearing, often worse lying down. A cough that lasts for weeks should be checked by a doctor, since there are other causes too.