A fever is an elevated body temperature, typically above 100.4°F (38°C), signaling the body’s response to infection or illness. During a fever, the body often sweats as it works to cool down, especially as the fever subsides.
How Your Body Regulates Temperature
The human body maintains a stable internal temperature, around 98.6°F (37°C), through thermoregulation. The hypothalamus, a brain region, acts as the body’s thermostat, monitoring and adjusting temperature. When the body gets too warm, the hypothalamus signals sweat glands to release moisture, cooling the skin as it evaporates.
The Rise of a Fever
A fever begins when pyrogens enter the bloodstream. These pyrogens can originate from outside the body, like bacteria or viruses, or be produced internally by immune cells. Pyrogens signal the hypothalamus to raise the body’s temperature set point, resetting the internal thermostat.
To reach this new, higher temperature, the body initiates heat-generating and heat-conserving mechanisms. This includes vasoconstriction, where blood vessels narrow to reduce heat loss from the skin, and shivering, muscle contractions producing heat. During this phase, a person often feels cold and may experience chills, even though their body temperature is rising.
The Role of Sweating in Fever
Sweating often occurs as the fever begins to “break” or subside. The hypothalamus lowers the body’s temperature set point. Since the body’s actual temperature is still elevated, the body needs to dissipate excess heat.
It increases blood flow to the skin through vasodilation, and sweat glands become more active. The evaporation of this sweat is the primary mechanism for cooling the body to its regular temperature. Sweating during a fever indicates the body is actively working to reduce its core temperature.
Understanding Sweating During Fever
Sweating during a fever is a positive sign, indicating the fever is “breaking” and the body is returning to a normal temperature. This shows the body’s natural cooling mechanisms are engaged. To support recovery, staying hydrated by drinking plenty of fluids is important, as sweating leads to fluid loss. Wearing light clothing helps facilitate heat dissipation. While sweating is a natural part of recovery, if excessive, accompanied by other concerning symptoms, or if the fever persists, seeking medical advice is advisable.