All biological tissues are dynamic. The fact that our bodies do not seem to change much disguises a constant state of flux, with the processes of decay and regeneration going on at the same time.

Bones are constantly being built up and worn away, as are joints. Atheroma (the build up of cholesterol plaque) is constantly accumulating inside the arteries, and just as constantly being removed.

If the processes are in balance the tissue remains intact, and good health is sustained.

But if the rate of decay is only a little faster than the rate of repair, there will be a net loss of healthy tissue. A pre-illness will be growing little by little every day until the clinical illness finally emerges.