Want more iVillage? Sign up for our
Newsletters
Body Temperature
About this test
What is body temperature?
Body temperature is a measure of the body's ability to generate and get rid of heat. The body is very good at keeping its temperature within a narrow, safe range in spite of large variations in temperatures outside the body.
When you are too hot, the blood vessels in your skin expand (dilate) to carry the excess heat to your skin's surface. You may begin to sweat, and as the sweat evaporates, it helps cool your body. When you are too cold, your blood vessels narrow (contract) so that blood flow to your skin is reduced to conserve body heat. You may start shivering, which is an involuntary, rapid contraction of the muscles. This extra muscle activity helps generate more heat. Under normal conditions, this keeps your body temperature within a narrow, safe range.
Where is body temperature measured?
Your body temperature can be measured in many locations on your body. The mouth, ear, armpit, and rectum are the most commonly used places. Temperature can also be measured on your forehead.
What are Fahrenheit and Celsius?
Thermometers
are calibrated in either degrees
Fahrenheit (°F) or degrees Celsius (°C), depending on the custom of the region.
Temperatures in the United States are often measured in degrees Fahrenheit, but
the standard in most other countries is degrees Celsius.
What is normal body temperature?
Most people think of a "normal" body temperature as an oral temperature of 98.6°F (37°C). This is an average of normal body temperatures. Your temperature may actually be 1°F (0.6°C) or more above or below 98.6°F (37°C). Also, your normal body temperature changes by as much as 1°F (0.6°C) throughout the day, depending on how active you are and the time of day. Body temperature is very sensitive to hormone levels and may be higher or lower when a woman is ovulating or having her menstrual period.
A rectal or ear (tympanic membrane) temperature reading is slightly higher than an oral temperature reading. A temperature taken in the armpit is slightly lower than an oral temperature reading. The most accurate way to measure body temperature is to take a rectal temperature.
What is a fever?
In most adults, an oral temperature above 100°F (37.8°C) or a rectal or ear temperature above 101°F (38.3°C) is considered a fever. A child has a fever when his or her rectal temperature is 100.4°F (38°C) or higher.
What can cause a fever?
A fever may occur as a reaction to:
- Infection. This is the most common cause of a fever. Infections may affect the whole body or a specific body part (localized infection).
- Medicines, such as antibiotics, narcotics, barbiturates, antihistamines, and many others. These are called drug fevers. Some medicines, such as antibiotics, raise the body temperature directly; others interfere with the body's ability to readjust its temperature when other factors cause the temperature to rise.
- Severe trauma or injury, such as a heart attack, stroke, heat exhaustion or heatstroke, or burns.
- Other medical conditions, such as arthritis, hyperthyroidism, and even some cancers, such as leukemia, Hodgkin's lymphoma, and liver and lung cancer.
Can a low body temperature be dangerous?
An abnormally low body temperature (hypothermia) can be serious, even life-threatening. Low body temperature may occur from cold exposure, shock, alcohol or drug use, or certain metabolic disorders, such as diabetes or hypothyroidism. A low body temperature may also be present with an infection, particularly in newborns, older adults, or people who are frail. An overwhelming infection, such as sepsis, may also cause an abnormally low body temperature.
Can a high body temperature be dangerous?
Heatstroke occurs when the body fails to regulate its own temperature, and body temperature continues to rise. Symptoms of heatstroke include mental changes (such as confusion, delirium, or unconsciousness) and skin that is red, hot, and dry, even under the armpits.
Classic heatstroke can develop without exertion when a person is exposed to a hot environment and the body is unable to cool itself effectively. In this type of heatstroke, the body's ability to sweat and transfer the heat to the environment is reduced. A person with heatstroke may stop sweating. Classic heatstroke may develop over several days. Babies, older adults, and people with chronic health problems have the greatest risk of this type of heatstroke.
Exertional heatstroke may develop when a person is working or exercising in a hot environment. A person with heatstroke from exertion may sweat profusely, but the body still produces more heat than it can lose. This causes the body's temperature to rise to high levels.
Both types of heatstroke cause severe dehydration and can cause body organs to stop functioning. Heatstroke is a life-threatening medical emergency, requiring emergency medical treatment.
| By: | Healthwise Staff | Last Revised: January 20, 2011 |
| Medical Review: | Susan C. Kim, MD - Pediatrics Thomas Emmett Francoeur, MDCM, CSPQ, FRCPC - Pediatrics | |
© 1995-2011 Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated. This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.
Welcome to Care Circle, an exclusive tool to help you take care of yourself and your loved ones. Here's how it works:
- Create profiles for yourself and your loved ones.
- Select the topics and conditions that interest each of you.
- Get customized news updates, original content, tools, and expert advice for each Care Circle member delivered directly to your personalized homepage.
The information you input is strictly private; you choose who has access to your Care Circle.
How do I add myself or someone else to my care circle?
Click on "Add someone." Fill out the short profile. Choose an avatar. Select the topics and conditions that interest this person from the pulldown menu. You can select as many as you want, but you must choose at least one. Click on "Add Someone" again. You should start getting updates immediately.
How do I save content to my Care Circle?
Click on "Manage My Care Circle." Select the tab of the person for whom you're saving content. Put your cursor over the piece of content that you want to save; a disk icon will appear in the righthand corner. Click on the disk and the piece of content will be moved to a save folder.
How do I add additional topics and conditions for someone in my Care Circle?
Click on "Manage My Care Circle." Select the tab for the person whose preferences you'd like to update. Under "Add More to Follow," select additional topics and conditions.
How do I delete topics and conditions for someone in my Care Circle?
Click on "Manage My Care Circle." Select the tab for the person whose preferences you'd like to update. Under "Follows," scroll over the topic or condition you want to delete. An "X" should appear on the righthand side. Click on the "X" and the topic or condition will be deleted from the list.
To manage your Care Circle, Please
Sign In.
from
- Facebook is now fueling organ donations
- Military women and suicide: Home safe but not sound
- Still in gear: Injuries don’t stop veterans on 100-day bike trek
- Ask Jenna: I've hit a weight loss plateau. What do I do?
- He poses in a tutu to laugh in face of wife's cancer
- After chemo hair loss, 'henna crowns' help heal
The iVillage Network