Why do we sleep? Why do we have chronic pain?

Suggestion that sleep is to cleanse all the areas of the body that have blood barriers.
Suggestion that without enough sleep, chronic pain develops in these blood barrier areas.

Sleep may be key for reducing pain. Sleep may be to cleanse those areas outside of the blood stream, or blood barriers.

There is a study that shows that during sleep the blood brain area is cleared through the glymphatic system (see below) . I suggest that this extends to the other blood barrier areas in the body, and that is why we sleep.

blood brain barrier (headaches)
blood spine barrier (back problems)
blood eye barrier (eye strain)
blood ear barrier (ear aches)
blood joint barriers (joint pain)
blood germ cell areas (sexual dysfunction)

Suggestion that the body, during sleep, works from head down and repeats the process 4 or 5 times a night - 4 or 5 cycles of NREM then REM.

NREM (80% of the time) active glymphatic system in blood barriers in brain, eyes, ears, (head area)
REM (20% of the time) active glymphatic system in blood barriers in spine, germ cells, joints. (body area)

BRAIN - BLOOD BRAIN BARRIER
SPINAL CORD - BLOOD SPINAL CHORD BARRIER
EYES - BLOOD RETINAL BARRIER
INNER EAR - BLOOD LABYRINTH BARRIER
PERIPHERAL NERVOUS SYSTEM - BLOOD NERVE BARRIER
JOINTS - BLOOD SYNOVIAL BARRIER
TESTIS - BLOOD TESTIS BARRIER

Report on Glymphatic system, brain, and sleep.

http://www.sciencedaily.com/releases/2012/08/120815142042.htm

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These posts are built on the premise of the evolution of catabolic and anabolic processes to other separate deconstructive and constructive processes.
Catabolic and anabolic processes evolve but they do not blend

This quote seems to support the above

Back pain is the most common type of chronic pain problem, and is the most prevalent medical disorder in industrialized societies. Not surprisingly, individuals with chronic back pain problems frequently report significant interference with sleep.

In a recent study, it was found that approximately two-thirds of patients with chronic back pain suffered from sleep disorders. Research has demonstrated that disrupted sleep will, in turn, exacerbate the chronic back pain problem. Thus, a vicious cycle develops in which the back pain disrupts one's sleep, and difficulty sleeping makes the pain worse, which in turn makes sleeping more difficult, etc.
from http://www.spine-health.com/wellness/sleep/chronic-pain-and-insomnia-breaking-cycle