Waking Up

A vampire expends one Vitae in the course of his daily slumber. If a Kindred falls asleep without any Vitae in his body (an unlikely event, but it could happen), he enters a longer torpor for a duration set by his Humanity and Blood Potency, just as if he had lost all his Health points to lethal damage. See the rules for torpor that follow.
For accounting on the character sheet, mark off the Vitae when the character awakens. Usually, the Vitae is counted as being spent at nightfall, the normal time for vampires to rise. If a Kindred forces herself to wake up during the day, the character must expend a Vitae. If the vampire lets herself sleep again before night falls, she expends another Vitae when she rises again that evening.