A fever is an elevated body temperature, typically 100 F (37.8 C) or higher. It is not an illness itself but a common symptom, indicating the body is fighting an infection. This temporary rise in temperature is a natural part of the immune system’s response.
The Body’s Fever Response
When pathogens, such as viruses or bacteria, enter the body, the immune system reacts by releasing substances called pyrogens. These pyrogens travel through the bloodstream to the brain, specifically to an area known as the hypothalamus, which acts as the body’s thermostat. The pyrogens signal the hypothalamus to reset the body’s internal temperature set point to a higher level.
To reach this new, elevated set point, the body initiates processes to generate and conserve heat. One common response is shivering, where muscles rapidly contract and relax to produce heat, which can make a person feel cold despite their rising internal temperature. Blood vessels near the skin’s surface may also constrict, shunting blood toward the body’s core to reduce heat loss. These actions continue until the body’s temperature matches the hypothalamus’s new, higher setting.
To Cover or Not
Understanding the body’s fever response is important when deciding whether to cover up. During the initial phase of a fever, when the hypothalamus is resetting the temperature upwards, it is common to feel cold, experience chills, or shiver. In this stage, using a light blanket or wearing an extra layer of clothing can provide comfort and help alleviate the uncomfortable sensation of being cold. The goal here is to reduce discomfort, not to “sweat out” the fever.
However, avoid excessive covering or bundling up, particularly once the shivering has stopped and the body has reached its new temperature set point. Over-bundling can trap heat, making it more difficult for the body to naturally cool down later and potentially leading to overheating. Once the fever begins to break or as the body works to lower its temperature, heat needs to escape through the skin. Light, breathable clothing and a single sheet or light blanket are recommended to allow for adequate heat dissipation.
If feeling warm or sweaty, it is advisable to remove excess layers to facilitate cooling. Conversely, if experiencing chills, temporary light covering is acceptable for comfort. The aim is to support the body’s natural processes without hindering its ability to regulate temperature effectively.
Additional Fever Management Strategies
Beyond managing clothing and covers, several other strategies can help manage a fever at home. Staying well-hydrated is important, as fever can lead to fluid loss through sweating and increase the risk of dehydration. Drinking plenty of clear fluids such as water, juice, or broth helps replenish lost fluids and can also soothe a sore throat if present.
Getting adequate rest is another important component of fever management. Physical activity can raise body temperature, so resting allows the body to conserve energy and focus on fighting the underlying infection. Over-the-counter fever-reducing medications, such as acetaminophen (Tylenol) or ibuprofen (Advil, Motrin), can help lower temperature and alleviate associated discomfort like muscle aches or headaches. Always follow the dosage instructions on the medication label.
When to Seek Medical Advice
While many fevers resolve on their own, certain situations warrant professional medical attention. For adults, a fever of 103 F (39.4 C) or higher should prompt a call to a healthcare provider. Immediate medical attention is necessary if a fever is accompanied by severe symptoms such as a severe headache, a stiff neck, unusual sensitivity to light, a rash, mental confusion, or difficulty breathing.
Specific concerns exist for infants and young children. A fever in an infant younger than three months with a rectal temperature of 100.4 F (38 C) or higher requires immediate medical evaluation. For older children and adults, a fever that persists for more than three to five days, or one that does not respond to fever-reducing medications, should also be assessed by a doctor. Any fever accompanied by seizures or difficulty holding down fluids also indicates a need for urgent care.