If the sympathetic nervous system is in a state of constant of anticipation, being conscious manages to maintain the correct balance between the sympathetic and parasympathetic systems by growing the latter's operation. That provides a sense of relaxation and peace.
When arousing the sympathetic, it brings us on high alert, also named the fight-or-flight reaction. For our existence, the sympathetic nervous system is important in helping us to react appropriately when there is a danger. These two mechanisms work with coordination as the other becomes less active as one will respond more active. Yet it can get them out of control.