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- When you have an illness or infection, your body temperature may rise above its normal range. This is a fever. It could help your body fight back against its cause.
- Most of us learned that a normal body temperature is 98.6 F. But new research shows that was the norm for people in the 1800s. Today, studies show that people may be slightly cooler, so the norm is anywhere between 97 and 99 F.
- If your temperature is higher than normal but it’s lower than 100.4 F, your doctor may say that you have a low-grade fever. A mild illness, like a cold or an ear infection, may cause one.
- If you have a fever, you may feel hot and sweaty. You also might shiver because you feel chilled. Weakness, aches, or fatigue could happen. You may have symptoms of the illness that caused the fever, like a cough or sore throat.
Feb 6, 2017 · Direct cellular damage: Hyperthermia is directly cytotoxic, becoming significant at 40C. Direct cell death in humans occurs at temperatures of around 41C. Cell death is intimately related to protein denaturation. Local effects: The inflammatory response is incompletely understood, but many pro- and anti-inflammatory mediators are released.
- Overview
- Symptoms
- Causes
- Complications
- Prevention
A fever is a temporary rise in body temperature. It's one part of an overall response from the body's immune system. A fever is usually caused by an infection.
For most children and adults, a fever may be uncomfortable. But it usually isn't a cause for concern. For infants, however, even a low fever may mean there's a serious infection.
Body temperatures vary slightly from person to person and at different times of day. The average temperature has traditionally been defined as 98.6 F (37 C). A temperature taken using a mouth thermometer (oral temperature) that's 100 F (37.8 C) or higher is generally considered to be a fever.
Depending on what's causing a fever, other fever signs and symptoms may include:
•Sweating
•Chills and shivering
•Headache
•Muscle aches
Typical body temperature is a balance of heat production and heat loss. An area in the brain called the hypothalamus (hi-poe-THAL-uh-muhs) — also known as your body's "thermostat" — monitors this balance. Even when you're healthy, your body temperature varies slightly throughout the day. It can be lower in the morning and higher in the late afternoon and evening.
When your immune system responds to disease, the hypothalamus can set your body temperature higher. This prompts complex processes that produce more heat and restrict heat loss. The shivering you might experience is one way the body produces heat. When you wrap up in a blanket because you feel chilled, you are helping your body retain heat.
Fevers below 104 F (40 C) associated with common viral infections, such as the flu, may help the immune system fight disease and are generally not harmful.
Fever or elevated body temperature might be caused by:
•A viral infection
•A bacterial infection
Children between the ages of 6 months and 5 years are at increased risk of a seizure that occurs during a fever (febrile seizure). About a third of the children who have one febrile seizure will have another one, most commonly within the next 12 months.
A febrile seizure may involve loss of consciousness, shaking of limbs on both sides of the body, eyes rolling back or body stiffness. Although alarming for parents, the vast majority of febrile seizures cause no lasting effects.
If a seizure occurs:
•Lay your child on the side or stomach on the floor or ground
•Remove any sharp objects that are near your child
•Loosen tight clothing
You may be able to prevent fevers by reducing exposure to infectious diseases. Here are some tips that can help:
•Get vaccinated as recommended for infectious diseases, such as influenza and COVID-19.
•Follow public health guidelines for wearing masks and social distancing.
•Wash your hands often and teach your children to do the same, especially before eating, after using the toilet, after spending time in a crowd or around someone who's sick, after petting animals, and during travel on public transportation.
•Show your children how to wash their hands thoroughly, covering both the front and back of each hand with soap and rinsing completely under running water.
•Carry hand sanitizer with you for times when you don't have access to soap and water.
Dec 10, 2023 · Fevers can arise as the body's defense system fights off an infection, but they can also be triggered by other things, including autoimmune diseases such as rheumatoid arthritis, or...
- Emily Cooke
May 22, 2023 · When to worry about fever. If you have a fever over 104°F (40°C), you should call your doctor. Seek medical help right away if you have a fever along with any of these symptoms: seizure; loss of consciousness; confusion; stiff neck; trouble breathing; severe pain anywhere in the body; swelling or inflammation of any part of the body
- hhp_info@health.harvard.edu
Mar 5, 2019 · During a fever, your body raises its temperature to fight infection, activating the immune system, causing chills, sweating and fatigue while suppressing pathogens. Here’s what happens to your ...
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Mar 31, 2020 · A fever is a natural response to an infection. However, it can be serious. Learn about the different types of fever and when to seek help.