Most people spend roughly one third of their whole lives sleeping. Despite its obvious importance to health, sleep remains mysterious in many ways. The debate of how much sleep we really need to be healthy has been going on for a long time, with different people claiming to need different amounts of sleep to feel rested and well. In the last few years, however, research conducted by experts in the field unequivocally supports the notion that the average adult needs between 7 and 9 hours of sleep per night.