you may be surprised to know that we are taller in the morning than we are at night. By virtue of the law of gravity, our bodies in the standing position, are attracted toward the ground. By the end of the day, the disks in the spine are compressed by the weight of the body, by the days tension and by things we have lifted. During the night, the spinal column is in a relaxed and spread out position.
Be aware of this fact and use this time to stretch out properly.