What is a normal body temperature? That question is harder to answer than you might think˳
The reality is that there isn’t one exact “normal” body temperature˳ Everyone has their own ordinary — and even that is more of a sliding scale than one set number throughout your lifetime˳
But there are ranges and trends to body temperature and times when you need to pay close attention to the reading on a thermometer˳ Let’s get the details from family medicine physician Donald Ford, MD, MBA˳
Normal body temperature range
Most people probably grew up being told a body’s normal temperature was 98˳6 degrees Fahrenheit (or 37 degrees Celsius)˳ That widely accepted number originated from a study done in the mid-1800s˳
But newer studies suggest the average person today actually runs a little cooler than that — somewhere between 97˳5 F (36˳4 C) and 97˳9 F (36˳6 C)˳
So, which number is correct? Well, probably all of them, says Dr˳ Ford˳ The truth is that your body temperature can move up and down and all around — though, it usually stays within a certain window˳
“Typically, anything in the range of 97 to 99 degrees Fahrenheit is considered normal,” he says˳ “But there are times when a perfectly healthy person might have a body temperature that’s slightly higher or slightly lower than that˳”
Age and average body temperature
Your “normal” body temperature changes throughout your life˳ It often rises from childhood into adulthood before dipping during the later years of life˳ By stages, it looks like this:
For younger children
The typical body temperature range for children between birth and 10 years old goes from 95˳9 F (35˳5 C) to 99˳5 F (37˳5 C)˳ This would be a temperature measured through an oral reading˳
For adults and older children
The typical body temperature range for people ages 11 to 65 is 97˳6 F (36˳4 C) to 99˳6 F (37˳6 C)˳
For older adults
The typical body temperature range for people older than 65 is 96˳4 F (35˳8 C) to 98˳5 F (36˳9 C)˳
What makes your body temperature rise?
A temperature that’s higher than 100˳4 F (or 38 C) is considered a fever, and it’s usually something you should bring to your doctor’s attention — especially if it lingers for more than two days, Dr˳ Ford says˳
Oftentimes, a fever is your body’s reaction to an infection or virus (like influenza)˳ A fever itself doesn’t require any specific treatment, other than trying to bring the temperature down for your comfort˳
Persistent low-grade or high-grade fevers could signal that something else is going on in your body˳ A number of medical conditions, including hyperthyroidism and other endocrine disorders, can raise your body’s core temperature˳
As for that gray area between a fever and the high end of a healthy temperature?
“We generally call this a ‘low-grade’ temperature,” Dr˳ Ford explains˳ “It’s certainly something to watch, but it’s hard to know the significance of this˳”
Fevers in children
Young kids generally tend to push thermometer readings higher than adults˳ Their bodies haven’t yet mastered the art of regulating their body temperature, so they’re also more likely to spike fevers — and severe ones, at that˳
“You may see a child that goes up to 103, 104, 105 degrees,” Dr˳ Ford says˳ “We recommend acetaminophen to try to prevent a rapid spike in temperature, which can induce some other problems˳”
If your child’s fever doesn’t come down with fever reducers, or if an infant younger than 3 months develops a fever, call your pediatrician˳
Is a low body temp bad?
Studies show that core body temperature decreases with age˳ Hypothyroidism, or an underactive thyroid, can also slow down metabolism, which can lead to a drop in body temperature˳
If your core body temperature dips down to 95 F (35 C) or lower, that’s considered hypothermia˳ It’s often caused by exposure to cold weather, but there are other factors that can put you at risk for hypothermia, such as age and certain medications˳
Hypothermia is a medical emergency, so call 911 if you suspect you or someone has hypothermia˳
The best way to take your temperature
If you take your temperature with three different kinds of thermometers, you might get three different results˳
A thermometer that goes under the tongue will likely give you a slightly higher reading than a forehead thermometer or one that goes under your armpit˳ (But those kinds may be easier to use with young kids˳)
Which is the most accurate? That would be a thermometer that goes under your tongue˳ “Testing an internal temperature is going to be more accurate than testing an external temperature,” states Dr˳ Ford˳
A rectal thermometer, typically used with young children, would be more accurate for the same reason˳ A thermometer used rectally should never be used orally to avoid spreading bacteria˳ Keep thermometers used orally and rectally separate and clearly marked˳
When should you take your temperature?
There’s usually a reason why you head to the medicine cabinet to grab your thermometer: Someone in the house doesn’t feel well˳
“Consider that the ideal time to take your temperature given the important information the reading provides,” says Dr˳ Ford˳ “Temperature is one of your vital signs, and it’s an important indicator of your health˳”
But know this: Body temperatures typically run a little lower in the morning and a bit higher in the afternoon˳ It also can fluctuate with menstrual cycles˳
Takeaways on temperature
A healthy body is generally pretty good at keeping its temperature at a comfortable level˳
“For example, if you go outside on a very cold day, you will notice that your skin temperature is going to go down but your core temperature inside will stay in the normal range,” explains Dr˳ Ford˳
A part of your brain called the hypothalamus is responsible for this˳ When you get too cold, it signals your body to preserve heat by shrinking the blood vessels, and to produce heat by shivering˳ And when you get too hot, it signals your body to make sweat to cool off˳
That’s why it’s normal for your temperature to change within a healthy range as you move through your day and your life˳
“‘Normal’ is a range, and people shouldn’t get worried if their temperature is varying a little bit within that range,” Dr˳ Ford advises˳ “That doesn’t necessarily mean anything good, bad or otherwise˳”
But if you have any questions or concerns about your temperature, don’t hesitate to call your healthcare provider˳
