I don't have the graph this excerpt talks about, but read this. There's a lot more to it. And thanks for asking for me.
Inversion Helps Provide Care and Feeding for the Discs
Your discs have three jobs: to separate the vertebrae, provide flexibility to the spine and to act as shock absorbers. Disc separation is especially important since all communication between the brain and the body is via nerves that pass between each vertebra. Insufficient distance between the vertebrae can result in nerve root pressure and pain.
The inner core of your discs is made of jelly-like material that provides the flexibility and "cushioning" in your back. When you are sitting, standing, or exercising (weight-bearing activities), fluid is squeezed out of your discs and into adjacent soft tissue (just as you would squeeze moisture out of a sponge). As a result, your discs lose some of their moisture and height. To prove this fact, measure yourself in the morning and then again at night. You will lose 1/2" to 3/4" in height by the end of the day. This lost fluid translates into your discs loosing some of their cushioning effect.
When you are sleeping, "a non-weight bearing activity", your discs (or "intra-vertebral sponges") expand as they soak up fluid and nutrients and increase the length of your spine by as much as 3/4". But you don't gain the full height back, accumulating to a total of 1/2" to 2" in height throughout your lifetime.
In fact, the only time in your life when you are giving your discs a break is when you are inverting. See graph. The medical study that generated this graph measured the pressure inside the 3rd lumbar disc - it was assigned a baseline pressure while standing of 100%. The study reported that even when you are lying down, the disc pressure remained at 25%. The hundreds of ligaments and muscles that encase and mobilize the spine act like a bunch of rubber bands holding the spine in compression equal to 25% of standing body weight. Inverting to 60 degrees is necessary to reduce the disc pressure to zero.3 Inverting is the most effective posture that allows your discs to recover from the constant pressure placed on them during your daily activities.
When your discs are compressed and thinned, your vertebrae potentially place more pressure on these nerve roots. More pressure equals more pain. As you relax, your spine begins to stretch. The space between each vertebra will increase, thus decreasing the pressure on the discs between each vertebra. This encourages fluid movement back into the disc, helping to keep your discs plump and happy and decreasing the pain in your back.
One technique many in the field believe is beneficial to helping to heal and regenerate the discs is to create a rocking motion. Often done for a few minutes AFTER a 15-20 minute inversion session at mild angles (coming up every 5 minutes or so to horizontal for a brief break from the traction). This rocking motion done after the inversion session creates a pumping action that facilitates circulation to the disc tissue which is infused by movement of the body. The rocking motion is done by rocking back to a 45-60 degree angle or so then rock forward so you are nearly upright then rocking back again. Doing this for a minute or so AFTER a 15-20 minute inversion session creates an accordion like pumping action that many believe can speed the recovery of the discs. This rocking motion is only recommended when one has been using the table for at least a week or two (or longer) and when pain symptoms are NOT present. One of the reasons discs degenerate and are difficult to regenerated is the nature of their passive circulation. Discs are not vascularised (full of blood vessels) like a kidney. Discs rely on body movement and breathing to get nutrients, fluids and remove waste products. This rocking motion or intermittent rhythmic traction is thought to facilitate a more rapid healing and regeneration process. When your are inverted a vacuum like pressure is created that pulls fluid into the disc and when you are upright the disc compressed and forces some fluid out. The rocking motion facilitates this circulatory process. We have had reports from people suffering with spinal stenosis that once they acclimated to inversion therapy the rocking motion aided them in reliving the pain. The movement of the vertebrae, discs and fluids seems to help many who have the condition of spinal stenosis.
!
