Psychology Today: Good sleep posture has your body relaxed and in alignment, and alignment starts with the position of your spine. When lying down for sleep, your spine should follow its natural curves.

There are 3 different curves in the spine: at the neck, the middle back, and the lower back. For these curves to fall naturally during sleep, the whole body must be supported. A strong sleep posture allows these natural curves to be maintained throughout the night. That means no crunching at your neck, no sagging of your lower back, and no rotation of your middle back. In addition to your spine in its natural position, good sleep posture has your hips, shoulders, and head lining up.

Think for a moment about good posture. Your head is held above your shoulders—not pushed back or craned forward—and your shoulders sit over your hips—not dipped forward or pushed behind. With the muscles of your core engaged, your spine follows its 3 natural curves.

The same basic posture applies to sleep. But there are some key differences: When we are awake, the muscles and ligaments of our body are working actively to hold our posture, whether we’re still or in motion. During sleep, the muscles and the ligaments relax. That relaxation is essential for the healing and rejuvenation of those tissues.

Our posture is more static—or stationary—during sleep than during most waking activities. We maintain static posture during the waking day, too—sitting in a chair, standing at a kitchen counter, etc. But at no point during the 24-hour day does our posture remain static for longer than it does during sleep.

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