I think that we can train our brain in order to be able to wake up every morning at nearly the same time. This happens when we go always to bed at the same hour. Even so, I do not leave out an alarm clock because on some accasions our brain can, as it were, to play with us.
May be we can trained to go always to bed at the same hour. When we do something consciously always at same hour or time, then that become a habit or an acquired behaviour . Consequetly, our brain will do it automatically and even we dont need to think about it, hence we becomme programmed to to it. But, when we are in spleep, we dream and we are in an unconscious state. Therefore , that led us to put the following question; how we can train our brain to do something at the same time while we are an unconscious state, in our case in the sleep state ?