Measurement of the temperature of warm-blooded organisms, esp. humans. The oral temperature of the healthy human body ranges between 96.6° and 100°F (35.9° and 37.8°C). During a 24-hr period, a person's body temperature may vary from 0.5° to 2.0°F (0.28° to 1.1°C). It is highest in late afternoon and lowest during sleep in the early hours of the morning. It is slightly increased by eating, exercising, and external heat, and is reduced about 1.5°F (0.8°C) during sleep. In disease, the temperature of the body deviates several degrees above or below that considered the average in healthy persons.
In acute infections such as meningitis or pneumonia, body temperature sometimes rises as high as 106° to 107°F (41.1° to 41.7°C).
Subnormal temperatures are sometimes seen in exposure, sepsis, or myxedema coma. In general, for every degree of fever, the pulse rises 10 beats per minute.