Sleeping and Spinal Decompression
There is a great video going around of former astronauts being interviewed about what it was like going into space. They speak about the experience in very cosmic/yogic terms. When astronauts leave earth’s atmosphere more than just their consciousness expands —they expand their spine as well.
The spine of an astronaut living weightless in space lengthens out, creating more space for the intervertebral discs. When they return from their journey they have a transition time for the spine to re-compress as they resume life in earth’s atmosphere.
While the lack of gravity is expansive, living life on earth is not quite the same. Let’s say you wake up in the morning and you are 5’7” tall. Over the course of the day your vertical posture will shrink about a quarter of an inch against the weight of gravity. When you go to sleep at night the spine will decompress and you will wake up 5’7” inches tall again.
There are many good reasons to get the right amount of sleep that your body needs. Giving your spine the time and space to decompress might be the most compelling one.