Side sleeping is by far the most commonly reported sleep position, and for good reason — it can have a whole lot of health benefits. If you snore
or have breathing problems, sleeping on your side is the best choice for opening your airways so you can breathe better at night, says sleep specialist W. Christopher Winter, MD, medical director of the Martha Jefferson Hospital Sleep Medicine Center in Charlottesville, Virginia.
Plus, it can be ideal for your spine and might help ease low back pain
. The slightly curled-in fetal position recreates the natural curve your spine had in the womb, before holding your head up, sitting down or walking around changed the curvature of your spine and potentially put stress on your lower back, explains Winter. Snoozing on your side can help give your spine a break from the tension from holding your head up, standing or sitting throughout the day.
Curling up on the right or left could also be good for your brain. One animal study found that sleeping on your side might lower the risk for developing Alzheimer's disease, Parkinson's disease and other neurological diseases. During the study, mice that slept on their sides had more efficient glymphatic systems compared to those that slept on their stomachs or backs. Why is this significant? Functioning glymphatic systems, which flush harmful waste products out of the brain, are key to preventing dementia and other neurological diseases.
It's not clear if these findings carry over into humans, says Winter, though he notes we remove waste from our brains much more effectively when we're asleep than when we're awake. Sleep plays a very active role in removing protein pieces called beta-amyloid that can cause Alzheimer's disease when they build up in the brain.
Similarly, sleeping on your left side, specifically, could help the flow of blood to your heart. When your heart pumps blood out to your body, it gets circulated and then flows back to your heart on the right side, Winter explains. If you sleep on your right side, the pressure of your body smashes up against the blood vessels that return to your ticker, but "sleeping on your left side with your right side not squished is supposed to potentially increase blood flow back to your heart." And anything you can do to help your most important organ pump more efficiently is good for your health, he says.
Pregnant women in particular should consider sleeping on their left side because the baby is pushing their organs upward, says Winter. (There's only so much space in there, after all!) During pregnancy, the heart is already working harder to support the baby, and snoozing on the right side, combined with the extra pressure from the organs, could hinder the flow of blood to mom's heart — and to the little one, says Winter.
The Bad: Ever slept on your side and woken up with a numb arm? That pins and needles feeling comes from "capillary crush," when the weight you're putting on your arm, or another numb body part, is putting intense pressure on your blood vessels. There can be so much crushing pressure that you lose blood circulation, explains clinical psychologist Michael Breus, PhD, a board-certified sleep specialist and author of "GOOD NIGHT: The Sleep Doctor's 4-Week Program to Better Sleep and Better Health." Eventually, you'll wake up and need to roll over.
Poor blood flow isn't the only downside to getting shut-eye while laying on your side. Studies show that it can increase acid reflux and heartburn at night. If you frequently suffer from indigestion at night, your best bet might be to choose another sleeping position.
Falling asleep on your back might help you wake up feeling much more refreshed
than usual. That's because sleeping on your back is the best position for getting high quality sleep, says Breus. It's the only position you can sleep in all night without having to readjust. When you sleep on your back, your weight is evenly distributed across your skeletal frame, unlike other positions. Translation: No more waking and tossing and turning because of tingly pain due to poor circulation in your arms or legs.
Plus, if you have lower back pain, sleeping on your back with your knees propped up by pillows could take some pressure off your spine and relieve pain. How? "As soon as you start to raise your knees, that secondary curvature of your spine [in your lower back] starts to go away," says Winter. The rounding in your lower back mimics the natural curvature of your spine that occurs when you're sleeping on your side, in the fetal position. Think of it this way: When you're lying flat on your back with your legs extended on the floor, you can probably fit your hand in the space between the floor and your lower back. But when your knees are up and your feet placed flat on the floor, you are easing some tension from the lower back all night long.
The Bad: While back sleeping is the optimal for many people, it's not for everyone. When you're on your back, your upper airway is the least stable, says Winter. The result? You might snore more or experience worse symptoms of sleep apnea, two conditions that can be annoying to bed partners and also potentially detrimental to your health.
The Good: If you're a back sleeper who snores and you can't switch to sleeping on your side, laying on your stomach could be a good compromise that can open your airways a bit, says Winter. But there aren't many other benefits to the face-plant approach.
The Bad: Sleeping on your stomach could be a pain in the neck — literally. Breus considers this the worst position because you have to turn your neck to almost an entire 90-degree angle from your body while also raising your head and neck up to pillow height. These crazy contortions could lead to neck pain. Plus, it's not great for your back, either. If you think of performing a "superman" back exercise while laying on your stomach, that's basically the back-bending position you're in all night long. "That curvature of your spine is actually going cause direct pressure on the lower part of your vertebrae," Breus says. "Over the course of time, it can cause low back pain."
Should You Switch It Up?
Whether you sleep on your side, back or stomach, if you wake up feeling refreshed and pain-free, there's probably no reason to break a habit that's working for you. But if you're having any of the issues mentioned here, it might be a good idea to experiment with something new.