How Your Sleep Position Affects Your Spine and Core

When we think about alignment and posture, we often think about how we stand, sit, or move—but how we sleep also plays a huge role in how our body feels and functions. At SOMA Movement Studio, we focus on intelligent movement and thoughtful positioning, but all that effort can be undermined by 6–8 hours of nightly misalignment. Hopefully, closer to 8 hours.

Let’s break down how common sleep positions affect your spine, core, and overall comfort—and how you can support better rest and better movement.

Back Sleepers: Neutral... with Caveats

Sleeping on your back is often considered the “ideal” position for spinal alignment. It allows the spine to rest in a relatively neutral position and places less pressure on your joints.

The challenge: Without the right support, your lower back can arch excessively, or your head may be elevated too much—both of which can strain the spine and surrounding musculature.

Pilates insight: If you’re already dealing with low back tension or anterior pelvic tilt, adding a pillow under the knees can help reduce strain and promote a more neutral pelvis. Also, be mindful of how many pillows you are using. Use of multiple pillows behind the head will reinforce head forward posture and hyperkyphosis, or roundness of the upper back. Of course, if you need multiple pillows to breathe comfortably that is more important, however if you can reduce the support behind your head, that will result in more neutral head alignment relative to the rest of your spine.

Side Sleepers: Popular, but Posturally Asymmetrical

Side sleeping is the most common sleep position—and it's generally fine—but it comes with a few quirks.

The issue: It can create lateral imbalances, especially in the hips and shoulders. If your top leg drifts forward, it can cause a mild spinal twist and tug on the low back. Over time, this can show up in the studio as tight QLs, cranky SI joints, or asymmetrical obliques.

Pilates tip: Try sleeping with a pillow between your knees, a small one in front of your chest to support your top arm, and a third under your rib cage. This keeps your spine and pelvis more aligned and reduces rotational tension. Think about how we lift the ribs in “sleeper” or side lying exercises on the mat and on the Reformer to bring the spine into alignment. The same applies in bed.

Stomach Sleepers: The Most Stressful for Your Spine

Sleeping on your stomach places your neck in a rotated position for hours at a time and encourages a compressed, extended lumbar spine. It also pulls your pelvis into an anterior tilt.

The result: Tension in the low back, tight hip flexors, and neck strain—all of which can affect your alignment, breath, and movement quality in class. Usually a twist in the spine as well because your head is turned.

If you must stomach sleep: Place a pillow under your hips to ease lumbar compression and consider training yourself toward a modified side position over time.

Sleep, the Nervous System, and Core Function

It’s worth noting that your sleep quality also affects your core. Poor sleep can dysregulate your nervous system, which in turn impacts how well your deep abdominal and pelvic floor muscles engage. That’s why Pilates emphasizes not just strength, but awareness—and why alignment matters, even while you sleep.

Small Changes, Big Results

You don’t have to overhaul your sleep habits overnight. Start by adjusting your pillow height, using props for better support, or shifting your position slightly. Many clients find that just a few tweaks dramatically reduce stiffness and improve their body’s readiness for movement.

If you’re waking up sore, stiff, or out of alignment, it might not be your workout that’s the problem—it might be your sleep setup.

Want more support?

Ask your instructor about alignment strategies that complement your sleep position—or join our October Sleep Challenge to explore how rest and movement work together for lasting strength.