Massage, whether conducted in a softly lit day spa or a treatment room at a physical therapy clinic, is something many people use to soothe sore joints and muscles, to ease anxiety or to help them sleep better. The National Center for Complementary and Alternative Medicine (NCCAM), part of the National Institutes of Health, reports that massage is one of the most popular complementary therapies used by Americans, with close to nine percent of adults using it. Until recently, little was known about why massage seemed to work, but recent research suggests that massage can affect the body’s production of certain hormones linked to blood pressure, anxiety, heart rate and other key vital signs.