The human body generates heat through metabolism, the chemical processes that occur in the body’s cells. Metabolism is regulated by a hormone called thyroid-stimulating hormone (TSH), which is secreted by the pituitary gland.
Normally, your body temperature is about 98.6 degrees Fahrenheit (37 Celsius). When you’re sick with a fever, your temperature will be higher than normal — sometimes as high as 104 degrees F (40 C). A low-grade fever of 100 degrees F (38 C) can make you feel sluggish and tired, but it’s not usually dangerous and won’t harm your health.
A high fever — 102 degrees F (39 C) or higher — may indicate a serious infection or other medical problem, requiring immediate medical attention.
Last modified: October 3, 2022