Library · Physiology
Fever
Make it clearer
Fever, which in medical terms is called pyrexia, is not simply being hot. It is core body temperature rising above a set point, that is, above the value the body actively defends. That value is fixed by the thermoregulatory center, which sits in the hypothalamus, a small area at the base of the brain that works like a thermostat.
What happens in fever is that the thermostat moves. Substances called pyrogens, which can come from outside the body or be produced inside it, raise that set point. The body does not overheat by accident: it moves the number its own thermostat defends.
Hyperthermia is something else. There the set point has not moved; temperature rises out of control. The difference is whether the thermostat moved or not.
In brief
Fever, or pyrexia, is a rise in core body temperature above the set point regulated by the thermoregulatory center in the hypothalamus.
It happens when endogenous or exogenous pyrogens raise that set point.
The body does not overheat by accident: it moves the number its own thermostat defends.
In hyperthermia the set point does not change and temperature rises out of control.
Sources (1)
- National Center for Biotechnology Information, StatPearls PublishingPhysiology, Fever, StatPearlsPublished
This page explains the topic in general terms; it does not tell anyone what treatment to follow.
Updated