First of all, when a person is in an upright state, the spine is not straight, but an S-shaped curve. When we sit down, the spine changes from an S shape to an arch shape. At this time, there will be a force compressing our intervertebral disc. After a long time, people will be very uncomfortable, and even lumbar pain. If it goes on like this, it will accelerate the degeneration or herniation of the disc, that is, “herniated disk”.
Studies have shown that the force on the lumbar spine and sacrum is 1.5 times that of the standard standing posture when we sit upright, 1.8 times that of the standard standing posture when we sit forward, and 2.7 times that of the standard standing posture when we lie on the table, and in the lying state, the force of the lumbar spine is only 25% of the standing position. Therefore, with different back angles, the pressure on the spine will be different.
That is to say, under normal circumstances, the more people lie back, the less pressure on the spine, so the best posture is to lie flat. When watching TV, we do not need to lie flat, but it is still recommended to choose a chair with a large reclining angle, which can be adjusted flexibly.