"When your conscientiousness impels you to take on more than you can handle, you begin to lose interest, even in tasks that normally engage you. You also risk your physical health. "Emotional labor," which is the effort we make to control and change our own emotions, is associated with stress, burnout, and even physical symptoms like an increase in cardiovascular disease. Professor Little believes that prolonged acting out of character may also increase autonomic nervous system activity, which can, in turn, compromise immune functioning."