What Causes a Fever?
Peter Nalin, associate professor of clinical family medicine and director of the family practice residency program at Indiana University, explains. Fever is an elevated temperature of the human body that is substantially beyond the normal range. Normal body temperature fluctuates daily from about one degree below 98.6 degrees Fahrenheit to one degree above that number. Lower body temperatures usually occur before dawn; higher temperatures in the afternoon. Body temperature also varies slightly depending on where on the human body it is measured. Rectal (internal) temperature tends normally to be higher than skin (surface) temperature. Oral and armpit temperatures can approximate actual body temperature and are more convenient to measure. The presence of a fever is usually related to stimulation of the body’s immune response. Fever can support the immune system’s attempt to gain advantage over infectious agents, such as viruses and bacteria, and it makes the body less favorable as a hos
