Certain postures—like putting your hands behind your head and your feet up on a desk—could make you feel more powerful by affecting your hormones levels, according to a study by Harvard Business School Professor Amy J.C. Cuddy and her two research partners at Columbia Business School.  Through high-power poses—ones that take up a lot of space—people who feel chronically powerless might become more confident, which in turn could lead to improvement of general health and well-being, according to the research.