Loss of sympathetic tone diminishes release of Nitric Oxide into the bloodstream, which in turn diminishes vasodilation in skeletal muscles during exercise. This might be expected to then alter muscle composition in some way.
“After interruption of sympathetic activity, a change in muscle fiber composition of the rabbit masseter muscle was observed. These changes consisted in atrophic and hypertrophic fibers, fiber splitting, necrosis and phagocytosis, and fibrosis. It was postulated that these changes in fiber types were due to redistribution of [the blood] flow resulting from sympathectomy”. (Hashmonai 2003) (See also Papa et al. 1986)
Atrophic and hypertrophic mean decreasing and increasing in size respectively. Necrosis means cell death. Phagocytosis is a process wherein a cell surrounds and ingests a bacteria or other object. Fibrosis is the forming of scar tissue.
Considering these very important discoveries in rabbits, human study of the effects of ETS on muscle composition is clearly in order. Patients should be warned of possible changes to muscle composition, based on animal data and the Hashmonai postulate.