Inverting would be considered passive compression
of soft body tissue, relative to lymphatic massage.
Obviously, there are other benefits but moving
lymph is a major one for me.
Here is another blurb which may help~~
"Inversion Helps Improve Circulation and Accelerates the Cleansing of Blood and Lymph Fluids
The cardiovascular system is your body’s transportation system, carrying food and oxygen to your body’s cells. Oxygen-rich blood from the lungs travels out through the arteries and waste-filled blood comes back through the veins to be cleansed and recharged with oxygen. Because your body must work against gravity to retrieve blood from your legs and lower torso, inversion can help to ease the circulation process by placing your body in a position that utilizes gravity’s force in your favor.
Unlike the cardiovascular system, the lymphatic system has no pump. Only the alternate contraction and relaxation of muscles moves lymphatic fluid through capillaries and one-way valves to the upper chest for cleansing. Inverting the body so that gravity works with, not against, these one-way valves helps to push the lactic fluid up to the chest. The faster the lymphatic system is cleared the faster the ache and pain of stiff muscles disappears."