Is sleeping on your left side better? Reflux, snoring and pregnancy

Sleeping on your left side is a good choice if you get acid reflux at night, because several studies link it to less acid in the esophagus than sleeping on your right side or your back. For snoring, the main win comes from being on your side at all, and the left-versus-right research is mixed. In pregnancy, the NHS says either side is safe. For everyone else, the most comfortable side is usually the right answer.

Is it better to sleep on your left side?

Sleeping on your left side is better for one well-studied problem: night-time acid reflux. For snoring and sleep apnea, the clearer benefit comes from avoiding your back, and either side works. Here's a quick summary of what the research says:

Does sleeping on your left side help acid reflux?

Sleeping on your left side does seem to help acid reflux at night. The studies consistently find less reflux when people lie on that side.

The earliest study here is from 1999 in the American Journal of Gastroenterology. Researchers followed 10 people with night-time reflux through the night with an acid probe and a position sensor. Lying on the right side was linked to more time with acid in the esophagus and slower acid clearance than lying on the left side, the back or the stomach.

A larger 2022 study in the same journal tracked 57 people having routine reflux tests, measuring their sleep position and esophageal acid at the same time. Acid exposure was significantly lower on the left side than on the right or the back. Acid also cleared faster on the left: a median of 35 seconds, against 76 seconds on the back and 90 seconds on the right.

The strongest evidence is a 2022 randomized, sham-controlled trial from Amsterdam. It enrolled 100 people with night-time reflux symptoms, advised all of them to sleep on their left side, and gave each a small wearable. In half of them, the device vibrated when they rolled onto their right side. In the other half, it was a sham. After treatment, 44% of the active group had at least halved their night-time reflux score, compared with 24% of the sham group. The active group spent about 61% of the night on their left side, against about 39% with the sham, and had more reflux-free nights.

The NHS also says sleeping on your left side can help heartburn in pregnancy, along with propping up your head and shoulders. If reflux is a regular part of your nights, our guide to acid reflux and a stuffy nose goes further.

Does the side you sleep on affect snoring?

The side you sleep on matters less for snoring than whether you're on your side at all. The NHS lists sleeping on your side among its main tips for snoring. A 2003 study in Sleep looked at 72 people who snored, using overnight sleep tests. Most of those without sleep apnea snored less, and less loudly, on their side than on their back. People with sleep apnea had more variable results and often kept snoring on their side.

Left versus right is less settled. A 2012 Turkish study of 131 people with suspected sleep apnea who spent similar time on each side found fewer breathing events on the right side than on the left, especially in more severe cases. But a 2026 study of 338 adults with sleep apnea found no significant difference between left and right, and lying on the back gave the highest event counts.

So for snoring, pick whichever side is comfortable and focus on staying off your back. Our guides to sleep position and snoring and why you still snore on your side cover what to do if side sleeping isn't enough.

Your nose and mouth matter too, whichever side you're on. If your nose feels tight, a nasal strip can make breathing feel easier, and if your mouth falls open, mouth tape keeps your lips closed so you breathe through your nose. The Titan Sleep System pairs both, and mouth tape and side sleeping explains how to keep tape in place when your face is on the pillow.

Which side should you sleep on when pregnant?

In pregnancy, the NHS says the safest position to go to sleep in is on your side, either left or right. It says research suggests that, after 28 weeks, going to sleep on your back can double the risk of stillbirth, possibly because of the flow of blood and oxygen to the baby.

The NHS also says not to worry if you wake up on your back. Just turn onto your side and go back to sleep. The NHS suggests supporting your bump with pillows and putting a pillow between your knees. You may have heard that the left side is best, but the NHS doesn't single it out for sleep safety, so choose whichever side lets you rest. Ask your midwife if you have questions about your own pregnancy.

Our guide to snoring during pregnancy covers what's normal and when to mention it. Check with your midwife or doctor before trying mouth tape or nasal strips while pregnant.

Is sleeping on your left side bad for your heart?

There's no good evidence that sleeping on your left side harms a healthy heart. The research on this topic is about people who already have heart failure.

A 2003 study in the Journal of the American College of Cardiology tracked sleep position in 75 people with heart failure and 75 people without it. The people with heart failure spent significantly less time on their left side than their right, while the comparison group showed no such difference. Those with larger hearts and poorer heart function avoided the left side the most. The authors suggested this might be a protective habit, perhaps to avoid discomfort from the enlarged heart's beat or extra strain on the heart.

If you have a heart condition and lying on one side feels uncomfortable or makes you short of breath, go with what your body tells you and mention it to your doctor. Our guide to sleep apnea and the heart covers the wider links between sleep and heart health.

How do you stay on your left side all night?

Staying on your left side all night can take some help. A few things make it easier:

• Start the night on your left side, with a firm pillow tucked behind your back so rolling over takes more effort.
• Put a pillow between your knees, as the NHS suggests for side sleeping in pregnancy.
• Try a tennis ball stitched to the back of your sleepwear, or a special pillow or wedge, which the NHS suggests for staying off your back.
• If reflux is the reason, the 2022 trial shows that a nudge when you roll right can work, though that was a specific medical wearable.

If snoring is why you're switching sides, a nasal strip from the Titan Sleep System can make nose breathing feel easier whichever way you end up facing. Don't stress if you wake up on the other side. In the trial, even the group with the most success still spent part of the night elsewhere. Our guide to the best sleep position for breathing has more on getting comfortable.

Can you use mouth tape on your side?

You can use mouth tape on your side, as long as your nose is clear and the tape stays put against the pillow. It's meant for adults who can breathe comfortably through the nose with the mouth closed. If you have reflux with acid or food coming up into your throat or mouth, read our guide to mouth tape and acid reflux before you start, because that changes the picture. We don't recommend mouth tape for children.

When should you see a doctor?

You should see a doctor if heartburn or reflux happens often, or if your snoring comes with other warning signs. The NHS advises seeing a GP if you feel sleepy during the day, your breathing stops and starts while you sleep, or you make gasping or choking noises, because these can be signs of sleep apnoea. Side sleeping, strips and tape don't treat sleep apnea.

A nose that's blocked most nights deserves a check too, since it makes every sleep position harder. If you're pregnant, ask your midwife about sleep position, heartburn or new snoring. If you have heart failure, talk to your care team about which positions feel best for you.

Our pick (paid partner): Titan Sleep System

If snoring or mouth breathing is part of your night, whichever side you sleep on, our pick is the Titan Sleep System. It's our recommendation, not the result of our own testing, and it isn't a reflux remedy. No published study has tested these products.

Titan describes it as TitanAir Nasal Strips and Titan Mouth Tape together as one nightly system. Titan says the strips are drug-free external nasal dilators with flexible, spring-loaded bands, worn just above the flare of the nostrils on the soft part of the nose. It says the tape is a bamboo silk strip worn horizontally across the lips, and suggests 20 to 30 minutes of daytime practice before the first night. Titan says both are third-party tested and certified PFAS-free, and both come with a 30-night guarantee.

Read next

• Does sleeping on your side reduce snoring?
• Mouth tape and acid reflux or nausea at night
• The best sleep position for easier breathing at night

* This content is for informational and educational purposes only and is not medical advice. It is not intended to diagnose, treat, cure or prevent any disease or health condition. Talk to a qualified healthcare provider about your health.