Definition
| Temperature Classification | |
|---|---|
|
|
|
| Hypothermia | <35.0 °C (95.0 °F) |
| Normal | 36.5–37.5 °C (97.7–99.5 °F) |
| Fever | >37.5–38.3 °C (99.5–100.9 °F) |
| Hyperthermia | >37.5–38.3 °C (99.5–100.9 °F) |
| Hyperpyrexia | >40.0–41.5 °C (104–106.7 °F) |
| Note: The difference between fever and hyperthermia is the mechanism. | |
A wide range for normal temperatures has been found. Fever is generally agreed to be present if the elevated temperature is caused by a raised set point and:
- Temperature in the anus (rectum/rectal) is at or over 37.5–38.3 °C (99.5–100.9 °F)
- Temperature in the mouth (oral) is at or over 37.7 °C (99.9 °F)
- Temperature under the arm (axillary) or in the ear (otic) is at or over 37.2 °C (99.0 °F)
In healthy adult men and women, the range of normal, healthy temperatures for oral temperature is 33.2–38.2 °C (91.8–100.8 °F), for rectal it is 34.4–37.8 °C (93.9–100 °F), for tympanic membrane (the ear drum) it is 35.4–37.8 °C (95.7–100 °F), and for axillary (the armpit) it is 35.5–37.0 °C (95.9–98.6 °F). Harrison's textbook of internal medicine defines a fever as a morning temperature of >37.2°C (>98.9°F) or an evening temperature of >37.7°C (>99.9°F) while the normal daily temperature variation is typically 0.5°C (0.9°F).
Normal body temperatures vary depending on many factors, including age, sex, time of day, ambient temperature, activity level, and more. A raised temperature is not always a fever. For example, the temperature of a healthy person rises when he or she exercises, but this is not considered a fever, as the set-point is normal. On the other hand, a "normal" temperature may be a fever, if it is unusually high for that person. For example, medically frail elderly people have a decreased ability to generate body heat, so a "normal" temperature of 37.3 °C (99.1 °F) may represent a clinically significant fever.
Read more about this topic: Fever
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