Some patients claim that they never run a fever. While many other patients claim to be ill even though their temperature is normal, saying My normal body temperature is 97.5 degrees, so I consider anything above that to be a fever for me. The 98.6-degree temperature benchmark was determined in 1861 by Dr. Carl Wunderlich, a German physician, who after measuring a million temperatures in healthy adults found the average to be 98.6. A 1992 study of adults under 40 found the actual mean oral temperature to be 98.2 degrees. Another more recent study, not surprisingly, found the elderly had an average temp of 97.4 degrees. Many of the elderly are clinically hypothyroid which will cause a much lower body temperature. So one does have to take into consideration the change from one’s normal temperature when evaluating whether a patient has a fever.
