There is a difference in height between morning and evening, and the height at night is 1.5 to 2.4cm or even 3cm shorter than that in the morning, while the medulla oblongata of the elderly has a small amount of water content, and the change in height is smaller. Many people will find that there is a height difference between morning and evening when measuring height. Generally speaking, the height difference between morning and evening ranges from 1.5 to 2.4cm, and can even reach about 3cm. This height difference originates from our spine, which consists of 33 vertebrae and 23 intervertebral discs. The difference between morning and evening in the spine is mainly due to the nucleus pulposus of the spine. Between the vertebrae and the vertebrae is the intervertebral disc, the intervertebral disc has a constituent structure called the nucleus pulposus, the water content in the human body at different stages can be 75-90%, under pressure, the nucleus pulposus makes the spinal column to bear the weight uniformly, the change of height is related to the change of water in the nucleus pulposus. Therefore, there is a difference in height between morning and evening, with 1.5 to 2.4 cm shorter in the evening than in the morning, while the elderly have less water content in the medulla oblongata, and their height changes are smaller. The difference in height measurement between morning and evening is a normal physiological phenomenon, and there is no need to worry too much about it. In order to make the measurement data accurate, it is recommended that people who need to have their height measured try to do it in the morning.