Understanding Chills
Chills are the body’s involuntary response to feeling cold or to an internal signal, often preceding or accompanying a fever. This sensation involves the rapid contraction and relaxation of muscles, generating heat to raise the body’s core temperature. You might observe visible shivering, trembling, or chattering teeth as these muscle movements occur. Goosebumps, where hairs on the skin stand up, can also accompany chills, though they are distinct from the muscle contractions that cause shivering.
This physiological process is the body’s attempt to regulate its temperature. While external cold can trigger shivering, chills often signal an internal thermal imbalance or an immune system response, indicating the body is fighting an illness or infection.
Chills and the Common Cold
Chills frequently accompany a common cold as the body’s immune system begins to fight the viral infection. When the body detects a pathogen, it releases substances that signal the brain to raise the internal temperature set point. This elevation in the body’s “thermostat” causes a temporary discrepancy: the body feels cold because its current temperature is below this new, higher target. To generate warmth, muscles involuntarily contract, leading to chills and shivering.
This process is part of the immune response, as many viruses and bacteria struggle to multiply effectively at temperatures slightly above 98.6 degrees Fahrenheit (37 degrees Celsius). Even a low-grade fever, common with a cold, can trigger chills as the body works to create an inhospitable environment for the virus. Not everyone with a common cold will experience chills, but their presence often signifies immune system activation.
When chills are part of a common cold, they appear alongside other familiar symptoms. These include a runny or stuffy nose, sneezing, a sore throat, fatigue, and a cough. Unlike the abrupt onset often seen with the flu, cold symptoms, including chills, tend to develop more gradually.
When Chills Indicate More Than a Cold
While chills can be a normal part of a common cold, their presence in certain contexts can indicate a more serious underlying condition. Chills accompanied by a very high fever, above 103°F (39.4°C), warrant medical attention, especially if the fever does not respond to medication. Other red flags include severe body aches, significant respiratory distress such as wheezing or shortness of breath, or chest pain. These symptoms suggest a more widespread or intense infection.
Chills occurring without the usual cold symptoms, like a runny nose or sore throat, should also prompt evaluation. The flu often presents with chills and fever, along with more severe body aches, headaches, and profound fatigue, with a more sudden onset than a cold. Bacterial infections, such as pneumonia, strep throat, or urinary tract infections (UTIs), commonly cause chills and fever. Symptoms like a stiff neck, severe abdominal pain, burning urination, or confusion alongside chills also necessitate immediate medical consultation.
Other conditions where chills are a prominent symptom include certain cancers, autoimmune conditions, or low blood sugar. If chills are persistent, frequent, or accompanied by extreme fatigue or other unusual signs, seeking professional medical advice is important. Consulting a healthcare provider is advisable for infants, young children with any fever, or adults with pre-existing medical conditions, as they may be at higher risk for complications.