National Geographic Documentary. Over the last three decades, science has been advancing our understanding of stress—how it impacts our bodies and how our social standing can make us more or less susceptible. From baboon troops on the plains of Africa, to neuroscience labs at Stanford University, scientists are revealing just how lethal stress can be. Research tells us that the impact of stress can be found deep within us, shrinking our brains, adding fat to our bellies, even unraveling our chromosomes. Understanding how stress works can help us figure out ways to combat it and how to live a life free of the tyranny of this contemporary plague. In Stress: Portrait of a Killer, scientific discoveries in the field and in the lab prove that stress is not just a state of mind, but something measurable and dangerous.