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Body temperature is a measure of how well your body can make and get rid of heat. The body is very good at keeping its temperature within a safe range, even when temperatures outside the body change a lot.
Your body temperature can be measured in many places on your body. The most common ones are the mouth, the ear, the armpit, and the rectum. Temperature can also be measured on your forehead.
Thermometers show body temperature in either degrees Celsius (°C) or degrees Fahrenheit (°F). The standard in Canada and most other countries is degrees Celsius. In the United States, temperatures are often measured in degrees Fahrenheit.
Body temperature is measured to:
Take your temperature a few times when you are well. This will help you find out what is normal for you. Check your temperature in both the morning and evening. Body temperature can vary by as much as 0.6°C (1°F) during the day.
Before you take your temperature:
Glass thermometers that contain mercury aren't recommended. If you have a glass thermometer, contact your local health unit to find out how to dispose of it safely. If you break a glass thermometer, call your local poison control centre right away.
Oral (by mouth) is the most common method of taking a temperature. For you to get an accurate reading, the person must be able to breathe through their nose. If they can't, then use the rectum, ear, or armpit to take the temperature.
Before you take a temperature, read the instructions for how to use your type of thermometer.
Ask the person to close their lips tightly around it.
Time yourself with a clock or watch. Some digital thermometers give a series of short beeps when the reading is done.
Clean a digital thermometer with cool, soapy water, and rinse it off before you put it away.
This is the most accurate way to measure body temperature. It's recommended for babies, small children, and people who can't hold a thermometer safely in their mouths. It's also used when it is very important to get the most accurate reading. Don't use a thermometer to take an oral temperature after it has been used to take a rectal temperature.
This will make it easy to insert.
Choose a quiet place so that the child won't be distracted or move around too much.
Time yourself with a watch or clock. Some digital thermometers give a series of short beeps when the reading is done.
Taking a temperature in the armpit may not be as accurate as taking an oral or rectal temperature.
Time yourself with a watch or clock.
An armpit temperature reading may be as much as 0.6°C (1°F) lower than an oral temperature reading.
Ear thermometers may need to be cleaned before they are used.
If dirty, wipe it gently with a clean cloth. Do not put the thermometer underwater.
Use a new cover each time you take an ear temperature.
Do not force it in.
Make sure nothing is between the thermometer cup and the skin.
Most of these thermometers make a beep or other sound when they are ready to read.
Forehead thermometers aren't as accurate as electronic and ear thermometers. If your baby is younger than age 3 months or your child's fever rises higher than 39°C (102°F), check the temperature again using a better method.
Pacifier thermometers are not as accurate as electronic and ear thermometers. If your baby is younger than age 3 months or your child's fever rises higher than 39°C (102°F), check the temperature again using a better method.
Taking an oral temperature causes only mild discomfort. You have to keep the thermometer under your tongue and hold it in place with your lips.
Taking a rectal temperature can cause a little discomfort, but it should not be painful.
Taking an ear temperature causes little or no discomfort. The probe is not inserted very far into the ear, and it gives a reading in only a few seconds.
Taking a temporal artery, forehead, or armpit temperature does not cause any discomfort.
There is very little chance of having a problem from this test.
When taking a rectal temperature, do not push the thermometer in more than 1.25 cm (0.5 in.) to 2.5 cm (1 in.). Pushing it farther can be painful and may damage the rectum.
If you tell your doctor about your temperature reading, be sure to say where it was taken: on the forehead or in the mouth, rectum, armpit, or ear.
The average normal temperature is 37°C (98.6°F). But that may not be normal for you. Your temperature also changes during the day. It is usually lowest in the early morning. It may rise as much as 0.6°C (1°F) in the early evening. Your temperature may also rise by 0.6°C (1°F) or more if you exercise on a hot day.
A woman's body temperature often changes by 0.6°C (1°F) or more through her menstrual cycle. It peaks around the time she ovulates.
Oral, ear, rectal, or temporal artery temperature
A rectal or ear temperature of less than 36.1°C (97°F) is a low body temperature (hypothermia).
You can take a temperature using the mouth (oral), anus (rectal), armpit (axillary), or ear (tympanic). But the temperature readings vary depending on which one you use. And you need an accurate measurement to know if a fever is present.
Medical research hasn't found an exact correlation between oral, rectal, ear, armpit, and forehead temperature measurements. In general, here's how the temperatures compare:
Current as of: July 1, 2021
Author: Healthwise StaffMedical Review: Susan C. Kim MD - PediatricsAdam Husney MD - Family MedicineMartin J. Gabica MD - Family MedicineKathleen Romito MD - Family MedicineJohn Pope MD - PediatricsDavid Messenger MD - Emergency Medicine, Critical Care Medicine
Current as of: July 1, 2021
Author: Healthwise Staff
Medical Review:Susan C. Kim MD - Pediatrics & Adam Husney MD - Family Medicine & Martin J. Gabica MD - Family Medicine & Kathleen Romito MD - Family Medicine & John Pope MD - Pediatrics & David Messenger MD - Emergency Medicine, Critical Care Medicine
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