What is the Difference Between Fever and Chills?

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Fever and chills are two symptoms that are often experienced together, particularly when the body is fighting off an infection or illness. They are related, but distinct, phenomena:

  • Fever: A fever is the body's normal reaction to an infection or illness, characterized by an increase in body temperature above the normal range (98.6°F or 37°C for humans). A fever is the body's attempt to raise its core temperature to an optimum level when fighting an infection.
  • Chills: Chills are a feeling of coldness that occurs during a high fever, but they can also sometimes occur on their own without a fever. Chills are caused by rapid muscle contraction and relaxation, and they are the body's way of producing heat when it feels cold. Chills often predict the coming of a fever or an increase in the body's core temperature.

Chills can be associated with various factors, such as being too cold, or they can be a symptom of certain illnesses. Some common illnesses that may cause fever and chills include colds or the flu, kidney or urinary tract infections (UTIs), bronchitis, strep throat, and ear infections.

To treat fever and chills, people can try over-the-counter anti-fever medications, such as acetaminophen, aspirin, or ibuprofen. Additionally, evaporation cools the skin and reduces body temperature, so sponging with lukewarm water (about 70°F or 21.1°C) may help reduce a fever. Drinking lots of fluids and getting plenty of rest are also recommended.

Comparative Table: Fever vs Chills

The main difference between fever and chills is that fever is a temporary rise in the body temperature, which is a part of the overall response from the immune system against infection, while chills are the sensation of feeling cold due to repeated expansion and contraction of muscles. Here is a table summarizing the differences between fever and chills:

Feature Fever Chills
Definition A temporary rise in the body temperature as a response to infection A sensation of feeling cold due to repeated expansion and contraction of muscles
Purpose Mechanism of the immune system to kill pathogens such as bacteria and viruses Often occurs with fever, but can also happen without fever
Causes Infection due to pathogens like bacteria and viruses Being cold, having hypothyroidism, infection (bacterial, parasitic, viral), intensive exercises in a cold environment, having anemia
Symptoms Feeling warm, flushed, or sweaty Feeling very cold, shivering, or shaking

Fever is often accompanied by chills, which are the body's way of raising its core temperature to an optimum level when fighting an infection. Chills can also occur on their own without a fever, such as when someone is cold or has a condition like anemia.