Low back pain after sleeping for a long time may be caused by the following mechanisms: First, it may be caused by muscle spasm in the lumbar region. If the patient sleeps for too long, it is possible that the lumbar region will remain fixed in a certain position for a long time. It may cause muscle spasm in the lumbar region, which in turn leads to pain in the lumbar region after the patient wakes up. Second, it may be caused by excessive pressure on the soft tissues of the lumbar region. If the patient sleeps too long, it may lead to bony protrusions of the lumbar region, causing excessive pressure on the surrounding soft tissues, for example, the patient may have inflammation due to excessive pressure on the soft tissues around the spinous process of the lumbar spine or around the posterior superior iliac spine, which may lead to lumbar pain. Thirdly, it may also be caused by insufficient muscle strength in the lumbar region. If the patient sleeps too long, it may lead to excessive relaxation of the muscles in the lumbar region for a long time, which will then cause a lack of muscle strength. At this time, the patient’s pre-existing diseases, such as lumbar vertebral body slippage may be exacerbated, which in turn leads to low back pain.