Understanding Body Temperature Measurement: Armpit vs. Mouth
When you're feeling under the weather, taking your temperature is a crucial step in understanding what might be going on. Two common methods for this are measuring your temperature in your armpit and in your mouth. But which one provides a more accurate reading? Let's dive into the details to help you make an informed decision when you need it most.
Armpit Temperature: The Basics
Taking an armpit temperature, also known as an axillary temperature, involves placing a thermometer under your arm. This method is generally considered the least accurate of the common oral, rectal, and axillary measurements. This is because the armpit is an external area, and its temperature can be easily influenced by the surrounding environment. Factors like how snugly the arm is held against the body, the amount of sweat present, and even the ambient air temperature can all play a role in the reading.
How to Take an Armpit Temperature
- Ensure the thermometer is clean.
- Place the tip of the thermometer in the center of the armpit.
- Bring the arm down firmly against the body to create a seal.
- Hold the thermometer in place for the recommended time according to the thermometer's instructions (usually longer than oral measurements, often 5-10 minutes for mercury thermometers and until it beeps for digital ones).
- Remove the thermometer and read the temperature.
Why it's less accurate: The armpit reading is typically about 0.5°F to 1°F (0.3°C to 0.6°C) lower than your actual core body temperature.
Mouth Temperature: The Standard
Measuring your temperature orally, or sublingually (under the tongue), is a widely used and generally more accurate method than armpit readings, especially for adults and older children. The mouth is a better indicator of core body temperature because it's a more protected cavity, less susceptible to external environmental influences compared to the armpit. However, even this method has its caveats.
How to Take a Mouth Temperature
- Ensure the thermometer is clean.
- Place the tip of the thermometer under the tongue, as far back as comfortable.
- Close your lips gently around the thermometer to keep it in place.
- Breathe through your nose.
- Keep your mouth closed and hold the thermometer until it beeps (for digital thermometers) or for the recommended time (for mercury thermometers, typically 2-3 minutes).
- Remove the thermometer and read the temperature.
Important considerations for oral temperature:
- Do not eat or drink anything hot or cold for at least 15-20 minutes before taking your temperature.
- Avoid smoking for at least 15-20 minutes before taking your temperature.
- These factors can significantly affect the accuracy of the reading.
Why it's more accurate: Oral temperatures are generally considered to be closer to your actual core body temperature than armpit readings. The accepted normal oral temperature is around 98.6°F (37°C), although this can vary slightly from person to person and throughout the day.
Comparing Accuracy: The Verdict
When directly comparing the two, mouth temperature is generally considered more accurate than armpit temperature for most individuals. This is because the oral cavity is a more stable internal environment compared to the external and variable conditions of the armpit. Healthcare professionals typically recommend oral temperature readings when possible for adults and older children.
However, it's important to note that even oral temperature readings can be influenced by recent activities. If accuracy is paramount, especially for infants and very young children where oral measurement might be difficult or unsafe, a rectal temperature is considered the gold standard for accuracy, reflecting the deepest core body temperature. Forehead thermometers (temporal artery thermometers) and ear thermometers (tympanic thermometers) are also widely used and offer convenience, though their accuracy can vary depending on proper technique and the device itself.
In summary: If you have the choice and are able to take a proper oral reading, it will generally provide a more accurate reflection of your internal temperature than an armpit reading.
Key Takeaway: For adults and older children, an oral temperature is typically more accurate than an armpit temperature. Always follow the specific instructions for your thermometer for the best results.
Frequently Asked Questions (FAQ)
How much lower is an armpit temperature compared to an oral temperature?
An armpit (axillary) temperature is typically around 0.5°F to 1°F (0.3°C to 0.6°C) lower than a true oral temperature. This difference is due to the armpit being an external area more influenced by the environment.
Why is mouth temperature more accurate than armpit temperature?
Mouth temperature is more accurate because the mouth is a more stable, internal cavity that is less affected by external factors like ambient air temperature and sweat, which can easily influence armpit readings.
When should I use an armpit thermometer?
Armpit thermometers are best used for infants and very young children when oral or rectal temperatures are not feasible or safe. They can also be used if a person is unable to hold a thermometer in their mouth, but it's important to remember the reading will be less accurate and may need to be adjusted by adding 0.5°F to 1°F.
Can I get an accurate reading from my armpit if I follow the instructions carefully?
While following instructions carefully can improve the reading, an armpit temperature will still generally be lower than your core body temperature. It can be useful for detecting a fever trend in infants, but for precise measurement, oral or rectal temperatures are preferred when possible.
