--a number of neuropathies are thought to be primarily circulatory or ischmeic in nature; autoimmune vasculitic neuropathies that tend to break down connective tissue such as blood vessel walls impair circulation so that nerves (and lots of other things) do not get the nutrition/oxygen they need or the removal of waste products that they should, and diabetic neuropathy also works primarily through a circulatory "nerve-starving" mechanism, so that anything that would improve circulation, allowing more blood to flow, would presumably be a good thing.

One of the benefits of exercise in general is the growth of and "cleaning" (removal of deposits) in small blood vessels, making the metabolic processes more efficient, which promotes healing as well as requiring less energy for the day to day biochemical processes. It's why anyone with almost any condition (there are a few exceptions) should be encouraged to exercise to tolerance--there are many good things that can happen when the body doesn't have to work as hard to get nutrients to and toxins from cells.