If the body is oscillated or moved up and down on an inversion table, it causes a pumping action which helps the fluids around the spinal discs to expel the waste out and help in spreading the fluid around the discs.

1. Inversion Therapy for Back Pain: Benefits, Frequency, Contraindications
http://www.epainassist.com/back-pain/inversion-therapy-for-back-pain

2. Inversion Therapy For Hair Growth: Can Hanging Upside Down Grow Hair?
http://www.epainassist.com/alternative-therapy/inversion-therapy-for-hair-growth

3. Shirshasana (Headstand) Versus Inversion Therapy Using Inversion Table
http://www.epainassist.com/articles/shirshasana-headstand-vs-inversion-therapy-using-inversion-table