On Nerve, an excited or nervous nerve, and muscle contraction
The heart is using the vagus nerve to listen to our external world, and digest it for value on how we feel about it, as we can see by the way the left vagus nerve connects to the AV node, and the right to the SA node, and their resepective recurrent branches wrapping around the aortic arch and subclavian artery to the thyroid, while the main branch continues to our digestive organ. We can hypothesize that being nerve - ous about danger would ask for muscle contraction, the energy for which loaded into the sympathetic nervous system, and this is healthy - but prolonged, all things fatigue, and can set up a pattern where there is depressed or less energy available for the system as it tries to hold together and protect the thing that probably no longer needs protection, stuck in an inertial fulcrum, a moment of time that has passed but being continued to be lived in.