What is high temperature / pyrexia / fever ?
A high temperature or fever, known as pyrexia, occurs when the body temperature rises above the normal level of 37 C if measured in the mouth, or 37.7 C if measured in the rectum. However, body temperature varies from person to person, usually between 36-37 C. Your own temperature will also fluctuate throughout the day as it is affected by factors such as sleep, exercise, eating and drinking; and for women, the stage of the menstrual cycle that has been reached. What causes high temperature? Most fevers are caused by pyrogens fever-inducing toxins released by viruses or bacteria. Pyrogens act on the temperature regulating centre in the brain. Common illnesses caused by such infection are the common cold, tonsillitis, influenza and urinary tract infections cystitis. Fever may also occur in non-infectious conditions such as dehydration, heart attack or cancer. In addition you can develop a high fever from over-exposure to heat, and especially to the sun. This is known as heat stroke. In
