If you're reading this in bed right now, there's a pretty good chance you're lying on your side. According to a 2024 SSRS survey of over 3,300 American adults, 69% of people report usually sleeping on their sides—making it by far the most popular sleep position in the country. Only 19% sleep on their backs, and just 12% are stomach sleepers.

But here's the interesting part: this wasn't always the case. When researchers compared seven different sleep surveys spanning 15 years (from 2010 to 2024), they found that side-sleeping has actually increased by about 8-10 percentage points. We're becoming a nation of side sleepers, and science might explain why.

Why Side Sleeping Wins

Sleep medicine specialists generally agree that side sleeping has the least negative impact on health compared to other positions. It's the best position for keeping airways open, which means less snoring and better breathing throughout the night. People with sleep apnea experience significantly worse symptoms when sleeping on their backs versus their sides.

Sleeping on your left side specifically offers some unique perks:

Helps prevent acid reflux by making it harder for stomach acid to creep into your esophagus
Promotes better blood flow to the uterus during pregnancy
May reduce swelling in legs and ankles
Could support the glymphatic system, which clears waste from the brain

A 2022 research study found that people without sleep disorders who prefer side sleeping actually sleep better than those who prefer back sleeping. When your body naturally gravitates toward a position, it's often trying to tell you something.

The Downsides Nobody Talks About

Side sleeping isn't perfect, though. The biggest issue? Your spine isn't in ideal alignment when you're curled up on your side, which can concentrate pressure on your neck, back, or hips. Many side sleepers wake up with shoulder pain from bearing their body weight all night.

There's also the vanity factor: dermatologists warn that side sleeping can lead to more wrinkles and acne on whichever side of your face constantly rubs against your pillow. Beauty-conscious sleepers sometimes try to alternate sides or invest in silk pillowcases to minimize the damage.

Sleep experts recommend placing a small pillow between your knees if you're a side sleeper. This simple trick helps keep your spine aligned and can significantly reduce hip and lower back pain.

What About Everyone Else?

The remaining 31% of Americans are split between back sleepers (19%) and the rare stomach sleepers (12%). Back sleeping is generally considered good for spinal alignment but can worsen snoring and sleep apnea. Stomach sleeping is widely considered the worst position—it strains your neck and back while offering few benefits.

Interestingly, people don't stay in one position all night. Sleep Foundation data shows that while adults prefer side sleeping, they actually spend about 54% of the night on their sides, 38% on their backs, and 7% on their stomachs. We're restless creatures, constantly shifting to find comfort.

The truth is, there's no universal "best" sleep position. Your ideal position depends on your individual health conditions, body type, and what simply feels comfortable. But if you're among the 69% of Americans who instinctively curl up on your side each night, rest assured—your body probably knows what it's doing.

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