Body temperature is a measurement of our body’s ability to make or expel heat.
When you are too warm, your body’s blood vessels widen to carry heat to your skin’s surface. You may begin to sweat to help your body cool.
When you are cold, your body’s blood vessels constrict, reducing blood flow to your skin so that your organs remain warm and working. You may start to shiver to help your body create heat.
A normal body temperature is about 36.5 degrees and this can change during the day depending on how active you are or due to hormone levels.
When the body’s temperature exceeds 37.7 - 38 degrees, this is known as a fever. Fever is the body’s reaction to infection, medications, sever trauma or injury and medical conditions.
So, if you need to measure someone’s temperature, what thermometer should you use?
There are many different types of thermometers you can use to monitor temperature.
- Digital: These are quick to use, reasonably accurate and can be used under the armpit.
- Ear thermometer: These are placed in the ear and takes a temperature reading within a second. However, they are expensive and the reading may not be accurate if it is not placed correctly in the ear.
- Strip-type thermometer: These are ones you hold to your forehead. This is not an accurate way of taking temperature.
- Mercury thermometers: Do not use mercury thermometers. These have not been used in hospitals for years and are no longer available to buy. These can break, releasing small shards of glass and highly poisonous mercury.
The Australian Government’s healthdirect.gov.au website recommends using a digital thermometer if available.
There are many ways you can take your temperature, these include:
- Tympanic: A thermometer is placed in the ear.
To do this, slowly pull the ear backwards to straighten the ear canal. Gently put the tip of the thermometer in the ear until it stops. If you are using a digital thermometer, you can remove the thermometer when you hear a beep.
- Axillary: The thermometer is placed in the armpit.
To do this, make sure the thermometer is placed in a dry underarm so that it only touches the skin and not clothing. Press the upper arm against the chest to keep the arm still and the thermometer in place. Axillary temperatures usually take a little longer, reading a book or watching TV might help to keep the person still. If you are using a digital thermometer this may take longer than 30 seconds.
- Oral: The thermometer is placed in the mouth under the tongue.
Ensure the person hasn’t had anything hot or cold to eat or drink for 20 minutes before you take the temperature. If the person is so sick they cannot control shivering it is best not to use this method. Place the tip under the tongue, close the middle of the mouth and close your lips. If you are using a digital thermometer, you will hear a beep in about 30 seconds.
- Rectal: The thermometer is paced in the bottom.
Use a thermometer with a stubby tip as this is less likely to tear the skin inside the bottom. Put a small amount of lubricant on the tip of the thermometer and slide the tip gently into the rectum. Hold the thermometer in place and if you are using a digital thermometer, you will hear it beep in about 30 seconds. If you are doing this to a child, ensure you put a cloth across your lap and place your child over the padding on their stomach or back – taking a temperature this way can cause the child to have a bowel movement. If your child is less than three months old, put the thermometer into the bottom only 1.25cm (or half an inch). If your child is older than three months, put the thermometer into the bottom about 2.5cm (an inch).
It is important to clean your thermometer before and after use with cool soapy water. Alternatively, you can disinfect it with an alcohol swap.
It is important to do this as a dirty thermometer may pass on an infection to another person.
Never use hot water, bleach or household cleaners on your thermometer and do not place in the dishwasher.
- Information sourced from: Australian Government, Department of Health