Sleeping or lying down in positions that weaken the muscles and stretch the ligaments of the lower back can cause poor posture and aggravate back problems and pain. The body curves inward naturally at the lumbar area, at the small of the back above the pelvis or hip bones. This curvature is called the lumbar lordosis, and it helps give strength to the vertebral column. Sleeping in positions that support this natural inward curve of the back and align the head with the spine and pelvis bones strengthens back muscles and ligaments to improve posture.
Head position when sleeping or lying down can affect the position of the entire body and increase stress on the spine and muscles of the back. The pillow should be below the head and neck, not the shoulders. Use a pillow that is firm enough to support the head and aligns it with the spine in its normal position. Using a very thick pillow or one that is too soft to support the head can cause neck and back pain and lead to poor posture.
Back and Knee Position
Sleeping with the back curved into a "C" shape can stretch the ligaments of the lumbar spine and weaken the muscles of the lower back. This can cause poor posture when sitting and standing. Keeping the back less rounded and with the lower back curved slightly inward when sleeping or lying on the side helps strengthen lower-back muscles and prevent hunched shoulder muscles and poor posture. When lying on the side, avoid curling the knees up toward the chest, and try placing a pillow between the knees to align the pelvis (hip) bones to the spine and head.
Lumbar Back Support
It is difficult to maintain sleep positions because it is natural to toss and turn and change positions when sleeping. Using a lumbar-roll cushion or a rolled-up towel to position the lower back can help ensure that sleep positions for good posture and back health are maintained throughout the night. Lumbar-roll cushions with waist ties help keep the lumbar support in place.
Support Body Curvatures
Soft mattresses can make the body sag in the middle, and they do not offer enough support to maintain correct body alignment when sleeping. Use a mattress that is firm enough to support the body in any sleeping position. If your mattress is not firm enough, place a board beneath the mattress for more support. A mattress that is too firm also does not support the natural curvature of the body. You should be able to comfortably sink into the mattress at normal pressure points but still be supported.