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What causes acid reflux and why it get worse at night
15th September, 2026 12:51 PM
For some people, the day may pass without much discomfort, only for a burning sensation in the chest to appear after getting into bed. Acid reflux can become more noticeable at night, making it difficult to sleep and sometimes leaving a sour taste in the mouth.
Acid reflux happens when stomach contents, including acid, move back up into the oesophagus, the tube that carries food from the mouth to the stomach. When this happens regularly and causes troublesome symptoms, it can develop into gastro-oesophageal reflux disease (GERD).
What causes acid reflux?
Normally, a ring of muscle at the bottom of the oesophagus opens to allow food into the stomach and then closes to prevent stomach contents from moving back up. When this muscle becomes weak or relaxes when it should not, stomach acid can travel upwards.
According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), factors such as being overweight, pregnancy, smoking and having a hiatal hernia can increase the likelihood of developing GERD. Some medicines may also contribute to the problem or make symptoms worse.
Food and eating habits can also play a role. Large meals, fatty or fried foods, spicy foods, coffee, alcohol, chocolate and other foods may trigger symptoms in some people. However, triggers are not the same for everyone.
Why symptoms are worse at night
One of the main reasons acid reflux can become more uncomfortable at night is the position of the body. During the day, a person is usually upright, allowing gravity to help keep stomach contents down.
When lying flat, gravity no longer provides the same help. If stomach acid moves into the oesophagus, it can remain there for longer and irritate.
Eating close to bedtime can make the problem worse because the stomach is still digesting food when a person lies down. According to the NIDDK, people experiencing reflux at night may benefit from eating meals at least three hours before lying down or going to bed.
Large evening meals can also put more pressure on the stomach, increasing the chance of reflux.
The signs to watch for
Heartburn is one of the most common symptoms of acid reflux. It can feel like a burning sensation in the middle of the chest and may rise towards the throat.
Some people also experience a sour or bitter taste in the mouth when stomach contents come back up. Others may have a persistent cough, hoarse voice, bloating or nausea.
Night-time reflux can be particularly disruptive because symptoms may wake someone from sleep or make it difficult to fall asleep comfortably. The NHS notes that acid reflux symptoms are often worse after eating, when lying down or when bending over.
Simple changes that may help
Changing the timing and size of evening meals can help reduce night-time symptoms. Avoiding foods and drinks that repeatedly trigger reflux is also useful.
People who regularly experience symptoms at night may also benefit from raising the upper part of the body during sleep rather than simply adding pillows under the head. Maintaining a healthy weight and avoiding smoking can also help reduce reflux symptoms.
Occasional heartburn is common, but frequent symptoms should not simply be ignored. Persistent acid reflux can irritate the oesophagus over time. Anyone experiencing frequent or severe symptoms, difficulty swallowing, unexplained weight loss, persistent vomiting or chest pain should seek medical attention.
Chest pain accompanied by difficulty breathing or pain spreading to the arm or jaw requires urgent medical attention because it can have causes other than acid reflux.
