[creekster]

A couple of random wonderings while riding this morning.

First, is the heart’s response to muscular exertion triggered by a chemical or a neurological signal? I know adrenalin can cause the HR to jump, but doesn’t it then stay elevated for a while? If chemical, are there “on and off” signals and are they limited in amount, meaning response gets weaker if used repeatedly in a short time frame? If neurological how does the cell demand for oxygen etc. get translated into a neurological signal?

Second, is the heart muscle susceptible to glycogen depletion like any other muscle? If you are on a no carb diet, for example, can the heart deplete its stored glycogen and if so what effect does this have on the heart’s performance?