According to research sleeping in complete darkness may help prevent weight gain and depression. Over eight weeks, mice exposed to dim lighting at night the equivalent of leaving on television, computer, or adjacent bathroom light-gained 50 percent more weight than mice in total darkness, despite similar caloric intakes and activity levels. And hamsters subjected to nighttime light experienced a rise in depressive behaviors. The light may throw off the biological clock and increase nighttime eating, says a doctoral student at Ohio State University in Columbus. If the findings hold true for humans, she adds people may benefit from a consistent sleep schedule and window curtains or sleep marks.
