Why we really do need more sleep

    The intervertebral disc is the largest avascular structure in the body.  This means that it has no direct blood supply.  It is able to get it's nutrients by a process of diffusion from the vertebral bones above and below them.  During the day when we are standing and sitting our spine is in a compressed state and there is a limited amount of diffusion that occurs.  When we go to be and lay down, our spine is able to decompress and as the vertebrae move further apart the discs inbetween them basically suck in the nutrients from the bones around them.  The disc becomes larger and the spaces between our vertebrae increase in distance.  Just think of the disc like a piece of memory foam, it takes a little time for the foam to become compressed and decompressed You can check this theory by looking in the mirrors in your car when you drive to work in the morning and when you leave work in the afternoon.  In the morning your disc are larger, but by the end of the day they shrink a little, which is why you might have to constantly adjust your mirrors.  
    This is also why people who are not able to get enough sleep may experience more back pain than someone who can get 8-9 hours/night.  When you are unable to sleep the muscles of you back are unable to relax and the disc are not able to decompress and take in the proper nutrients.  In turn the disc do not 'inflate' and they remain in a compressed state, resulting in nerve irritation and increased hypomobility.  Chiropractors can help to break the cycle of pain, therefor allowing them to sleep and feel better.  Along with chiropractic care, you may also want to look into purchasing a new pillow or mattress if yours is over 10 years old.