How It Feels
Taking your temperature by mouth is only mildly uncomfortable,
since you must keep your mouth closed and breathe through your nose while the
thermometer is in place.
Taking a rectal temperature can be
slightly uncomfortable but should not be painful.
temperature with an ear thermometer causes little or no discomfort. It is not
inserted very far into the ear, and it provides a reading in only a few
seconds. For this reason, the ear thermometer is widely used in doctor offices and hospitals. But it may be less accurate than rectal
Taking your temperature with a thermometer that is placed on the skin, such as a plastic strip
thermometer or a temporal artery thermometer , should not cause any discomfort. Use of a plastic strip thermometer feels like having an adhesive bandage on your forehead. The slight pressure of a temporal artery thermometer as it glides across the skin is not painful.
There is very little risk of complications from
taking a temperature.
When taking a rectal temperature, do not
insert the thermometer into the rectum more than
0.5 in. (1.25 cm) to
1 in. (2.5 cm). Further
insertion can be painful and may damage rectal tissues.
Body temperature is a measure of the
body's ability to generate and get rid of heat.
When you tell your doctor about your temperature
measurement, be sure to mention whether it was taken on the forehead or in the
mouth, rectum, armpit, or ear.
The average normal temperature
is 98.6 °F (37 °C). But "normal"
varies from person to person. Your temperature will also vary throughout the
day, usually being lowest in the early morning and rising as much as 1°F
(0.6°C) in the early evening. Your temperature may also rise by 1°F (0.6°C) or
more if you exercise on a hot day. A woman's body temperature typically varies
by 1°F (0.6°C) or more through her
menstrual cycle, peaking around the time of
Oral, ear (tympanic), rectal, or temporal artery temperature
- Fever: 100.4 °F (38 °C) to 103.9 °F (39.9 °C)
- High fever: 104 °F (40 °C) and higher
Armpit (axillary) temperature
- Fever: 99.4 °F (37.4 °C) to 102.9 °F (39.4 °C)
- High fever: 103 °F (39.5 °C) and higher
A rectal or ear temperature of
less than 97 °F (36.1 °C)
means a low body temperature (hypothermia).
What Affects the Test
Inaccurate temperature readings
can be caused by:
- Not keeping your mouth closed around the
thermometer when taking an oral temperature.
- Not leaving a
thermometer in place long enough before reading it.
- Not putting the
proper thermometer in the right place.
- Not following the
instructions for proper use that come with the thermometer.
- A weak
or dead thermometer battery.
- Taking an oral temperature within 20
minutes after smoking or drinking a hot or cold liquid.
- Taking a
temperature by any method within an hour of exercising vigorously or taking a