We’re constantly asked to pick a side—in politics, in sports, even in pizza crust. But what about in bed? If you’re among the estimated 60 percent of adults who sleep on their side, you might not have given much thought about which side you’re sleeping on. Does it even matter?
Yes and no. While experts agree that the best sleeping position is the one that helps you get consistently restorative slumber, research suggests that left-side sleeping offers an advantage over the right when it comes to your health and well-being. Plus, certain conditions (like sleep apnea and acid reflux) might make your go-to sleeping position less than ideal. Knowing which side is most likely to help you sleep (and feel) better could make it easier to switch things up.
Here’s why the left is the best side to sleep on, how sleeping positions affect your health and reasons to roll over to the other side.
Why You Should Sleep on Your Left Side
Comfort should always come first when it comes to sleep (after all, that’s what’s going to help you get high-quality Zzz’s). But if we’re talking about which sleeping position offers the most science-backed health benefits, the left side wins, says Andrew Colsky, LPC, LMHC, a behavioral sleep medicine clinician and founder of the National Sleep Center.
“There are pros and cons to each sleeping position, but if you had to choose, the left side should be your first pick,” he says.
The biggest benefit of sleeping on your left side has to do with digestion. According to the Cleveland Clinic, this sleep position keeps your lower esophageal sphincter—the muscle that prevents food and stomach acid from flowing back up—nestled in an air pocket just above your stomach, making it easier to do its job.
For people who are prone to heartburn or individuals with gastroesophageal reflux disease (GERD), which causes chronic acid reflux, sleeping on the left side can be a game-changer for finding relief during the night. One study that measured the pH level in participants’ esophagi found that those who slept on their left side had significantly less acid in their throats at night than those who slept on their right side or back. The acid left-side sleepers experienced also cleared significantly more quickly, which may, in turn, help you get better sleep. Researchers have found that while GERD can lead to poorer sleep quality, the impact is much less severe for left-side sleepers than right-side sleepers.
Beyond digestion, your sleep position might also play a role in circulation and organ function.
“It’s thought that sleeping on the left side may promote better blood flow,” notes Stephanie M. Stahl, MD, associate professor of clinical medicine and director of the sleep medicine fellowship program at Indiana University School of Medicine.
The Mayo Clinic explains that left-side sleeping lessens pressure on the organs, especially the liver and kidneys, and promotes healthy blood flow. This is especially important during pregnancy. Sleeping on your left side allows the most blood flow to reach a growing fetus, according to Stanford Medicine.
While not unique to the left, side-sleeping in general is considered the best position for improving symptoms of obstructive sleep apnea, a condition that affects nearly 30 million Americans, according to the American Academy of Sleep Medicine.
“Obstructive sleep apnea is where the tongue and surrounding tissues collapse the back of the throat repeatedly. When we sleep on our back, it makes it more likely to have obstructions near the airway,” says Stahl.
Sleeping on your side, however, can help keep the airways open, which eases mild apnea and even reduces snoring.
It’s worth noting that lying on your stomach can also alleviate sleep apnea symptoms, but it’s not the ideal sleeping position due to the extra tension it can create in the back, neck and shoulders. Spending seven to nine hours in that position can cause much discomfort, hence why experts encourage side-sleeping over lying face down.
Scientists continue to research the pros and cons of different sleeping positions, but early research shows that side-sleeping may support brain health, as well. The findings of a 2015 study suggest that sleeping on your side can help remove waste from the brain and potentially reduce the risk of neurological diseases like Alzheimer’s and Parkinson’s.
“The research isn’t conclusive, but there may be a relationship between sleeping position and clearing out amyloid plaques and other garbage that can build up on the brain,” says Colsky.
The Best Sleep Position Is the One That Works for You
While more research is needed on the optimal sleeping position for our health and well-being, the left side has the strongest evidence supporting its benefits. Studies suggest it may improve blood flow, ease sleep apnea symptoms and reduce acid reflux.
With that being said, everyone’s body is different, and we all have a natural tendency to feel more comfortable in one position than another. If your current sleep position doesn’t exacerbate any health conditions or cause discomfort, there’s no reason to force a change.
“Without an issue like sleep apnea, truly whatever position people are most comfortable in is the one they should sleep in,” says Stahl.
Even though left-side sleeping has its perks, it may not be worth the frustration of trying to force a new habit—especially if it comes at the cost of quality rest.
“If somebody hears that the number one choice is sleeping on their left side, they start to train themselves. There’s nothing wrong with that, but if your body is naturally fighting it and doesn’t like to sleep on that side, you can create anxiety for yourself, which makes it hard to sleep,” Colsky says. “It’s important to listen to your body.”
When You Might Need To Sleep in Another Position (And How To Do It)
Changing your bedtime posture isn’t always easy. The first few weeks of making the transition can feel strange, and it usually takes about 12 weeks for the position to become your new norm, says Colsky.
Still, there are some reasons why you might need to sleep in another position, including:
- Injuries
- Health conditions like obstructive sleep apnea, acid reflux or GERD
- General discomfort
- Chronic pain
- Recovery from surgery
- Pregnancy
- Circulation issues
- Snoring
If you find yourself in a position where you need to change positions, there are ways to make the adjustment period feel less like a bad dream. Start by giving your body support in the places it needs it most in the new position. “In general, we want to keep our spine fairly aligned from the neck to the lumbar area, so pillows are really important. If you’re sleeping on your side, putting a small pillow between your legs can help keep your spine aligned,” advises Stahl.
Even if you successfully drift off in the new position, your body might want to revert back to your preferred sleeping style in the middle of the night. You can wear certain devices to encourage your body to stay in a specific position, though.
“I recommend starting with something simple at home, like wearing a fanny pack with a few tennis balls tucked in on your back,” says Stahl. This can help prevent you from rolling onto your back in the middle of the night.
If that doesn’t work, you could try a positional therapy device. These use other techniques, like gentle vibrations, to nudge you out of unwanted positions and into your target posture. These devices often require a prescription, so talk to your doctor to see if it’s right for you.
Finally, try to avoid feeling frustrated or stressed during the transition period. Changing any habit requires time and patience. The key to making the change is to remain consistent. At the end of the day, the best sleep position is the one that lets you wake up feeling rested, even if it takes some time (and a little awkwardness) to get there.
