by Carly Casella via Science Alert Headline Image: (Tim Hawley/DigitalVision/Getty Images) The human body is often said to rest at a healthy internal temperature of 37 degrees Celsius, or 98.6 degrees Fahrenheit. This average was established two centuries ago in France, and yet in the meantime, it seems our 'normal' physiology has changed ever so slightly. Early last year, researchers in the United States combed Civil War veteran records and national health surveys and found temperatures among men born at the turn of this century were 0.59 degrees Celsius cooler than those men born around two hundred years earlier. Women, on the other hand, had seen a 0.32 degrees Celsius decline since the 1890s. At the time, the authors suggested it might have something to do with inflammation due to disease, which is closely tied to body temperature. With the rise of modern medicine, we've seen a decline in chronic infections, and maybe, the authors suggested, this has chilled us out, so to speak.