Stamina
A measure of a character's endurance, Stamina measures their capacity for physical activity. Running and fighting can use up a character's Stamina quickly. Unlike Health and Mana, Stamina increases very little over time.
Unless modified by a power, Stamina recovery is a constant which is independant of race, class, Constitution, total Stamina, or any other statistic. It is three times faster while sitting than standing, however, and recovery is zero while actually walking. Running, flying, walking and swimming consume stamina.