Let's consider this scenario: You do sports in the morning in a fasted state (i.e. without consuming any calories after waking). Your brain of course needs glucose and your liver probably still has some of it in stock. So it keeps releasing it. Is there a mechanism to prevent the working muscles from consuming the glucose (so that the brain can be supplied longer)? If yes, how does it work?
(Please answer not too technically, so that people outside this area can also understand it.)