top of page
  • Health & Wellness 101

What is a Normal Body Temperature?

Body temperature is a crucial biomarker that reflects the metabolic activity and health status of an individual. It is an essential parameter used to assess the presence of infection or illness, as well as monitor the effectiveness of treatment.

 Normal Body Temperature

The concept of "normal" body temperature has been ingrained in medical practice for centuries as a reference point for health assessment. However, recent research has shed light on the variability of body temperature among individuals and the need for a more nuanced understanding of what is considered "normal."

In this article, we will explore the historical context of "normal" body temperature, the factors contributing to its variability, methods to measure body temperature accurately, how to recognize and respond to abnormal body temperatures, the biological mechanism behind body temperature regulation, and key takeaways for monitoring body temperature.

The Historical Context of "Normal" Body Temperature

The widely accepted notion of "normal" body temperature as 98.6°F (37°C) was first introduced by German physician Carl Reinhold August Wunderlich in the mid-19th century. Wunderlich's studies involved measuring the axillary temperatures of over 25,000 patients. They found that most individuals had a body temperature within a narrow range.

This value became widely adopted as the standard for normal body temperature and has been taught in medical schools and used in clinical practice ever since.

However, recent studies have challenged the notion of a fixed "normal" body temperature. Research conducted over the past few decades has shown that average body temperature can vary widely among individuals.

A study published in the journal eLife in 2020 analyzed temperature measurements from over 35,000 adults and found that the average oral temperature was lower than the commonly accepted 98.6°F (37°C). The study suggests that the average body temperature has actually decreased by about 0.59°F (0.33°C) since the time of Wunderlich's studies.

Variability in Body Temperature: Why It's Not the Same for Everyone

Several factors contribute to the variability in body temperature among individuals. These factors include age, gender, time of day, and external factors such as environmental temperature.

Age-Related Differences in Body Temperature

Body temperature varies with age. Newborns have higher body temperatures than adults, with an average axillary temperature of around 99°F (37.2°C). As children grow, their body temperature gradually decreases and reaches adult levels by the age of 18.

Elderly individuals may have lower body temperatures than younger adults, with average axillary temperatures ranging from 97°F to 97.5°F (36.1°C to 36.3°C).

Besides, older people may have difficulty regulating their body temperature, making them more susceptible to hypothermia or heat stroke.

The Role of Gender in Body Temperature Variability

Gender also plays a role in the variability of body temperature. Women tend to have slightly higher body temperatures than men. This difference is attributed to the effects of female hormones, specifically estrogen, which can increase metabolic activity and raise body temperature.

Women may also experience hormonal fluctuations during their menstrual cycle, which can cause temporary increases in body temperature.

Daily Fluctuations in Body Temperature

Body temperature is not constant throughout the day; it naturally fluctuates in a circadian rhythm. The body's temperature is typically at its lowest in the early morning and gradually increases throughout the day, peaking in the late afternoon or early evening. This variation can range from 0.5°F to 1°F (0.3°C to 0.6°C).

These daily fluctuations in body temperature should be taken into account when assessing an individual's temperature.

Methods to Measure Body Temperature

There are several methods available to measure body temperature accurately, each with its advantages and limitations. The most commonly used methods include oral, tympanic, axillary, and rectal measurements.

Oral vs. Tympanic vs. Axillary vs. Rectal Measurements

Oral temperature measurement involves placing a thermometer under the tongue and waiting for an accurate reading. This method is widely accessible and easy to perform.

Oral temperature measurement

Tympanic temperature measurement uses an infrared thermometer to measure the temperature of the ear canal. It is quick and non-invasive, but it can be affected by external factors such as earwax or ear infections.

Axillary temperature measurement involves placing a thermometer in the armpit and waiting for a reading. It is less accurate than oral or rectal measurements but is considered a safe and convenient method, especially for children.

Rectal temperature measurement is the most accurate method as it reflects core body temperature. However, it is also the most invasive and may only be suitable for some age groups.

The Importance of Accurate Temperature Measurement

Accurate temperature measurement is crucial for proper health assessment and diagnosis. Inaccurate measurements can lead to misdiagnosis and inappropriate treatment. It is essential to follow proper procedures and guidelines when measuring body temperature to ensure accuracy.

This includes using the appropriate method for the individual and ensuring proper calibration and hygiene of the thermometer.

Recognizing and Responding to Abnormal Body Temperatures

Understanding what constitutes an abnormal body temperature is essential for recognizing and responding to potential health issues.

When is a Temperature Considered a Fever?

A temperature above the accepted range of normal body temperature is considered a fever. For adults, a temperature of 100.4°F (38°C) or higher is generally considered a fever.

However, it is important to consider the individual's baseline body temperature and any other symptoms they may be experiencing. Fever can be a sign of infection or illness and may require medical attention.

Understanding Hypothermia: Causes and Symptoms

On the other end of the spectrum, abnormally low body temperature, known as hypothermia, can also be a cause for concern. Hypothermia occurs when the body loses heat faster than it can produce it, resulting in a body temperature below 95°F (35°C). It can be caused by exposure to cold environments, certain medical conditions, or intoxication.

Symptoms of hypothermia include shivering, confusion, loss of coordination, and unconsciousness. It is a medical emergency that requires immediate treatment.

The Role of Medications and Health Conditions in Temperature Fluctuations

Certain medications and health conditions can also cause fluctuations in body temperature. For example, fever is a common side effect of certain medications, such as antibiotics, antiepileptics, and antipsychotics.

Additionally, certain health conditions, such as thyroid disorders, can affect body temperature regulation and lead to abnormal temperature readings. It is important to consider these factors when assessing an individual's body temperature and interpreting the results.

The Biological Mechanism Behind Body Temperature Regulation

Body temperature regulation is a complex process involving various physiological mechanisms. The hypothalamus, a region of the brain, plays a crucial role in maintaining body temperature within a narrow range.

When body temperature rises above the set point, the hypothalamus triggers mechanisms to cool the body, such as vasodilation (expansion of blood vessels) and sweating.

Conversely, when body temperature falls below the set point, the hypothalamus initiates mechanisms to warm the body, such as vasoconstriction (narrowing of blood vessels) and shivering.

Key Takeaways and Recommendations for Monitoring Body Temperature

In conclusion, the concept of "normal" body temperature is more nuanced than previously believed. Average body temperature can vary among individuals and is influenced by factors such as age, gender, and time of day. It is important to consider these factors when assessing body temperature and interpreting the results. Accurate measurement of body temperature is crucial for proper health assessment and diagnosis.

Different methods, such as oral, tympanic, axillary, and rectal measurements, have their advantages and limitations. It is recommended to follow proper procedures and guidelines for accurate temperature measurement. Recognizing and responding to abnormal body temperatures, such as fever or hypothermia, is essential for identifying potential health issues and seeking appropriate medical attention.

Factors such as medications and health conditions can also contribute to temperature fluctuations. Understanding the biological mechanisms behind body temperature regulation can provide a deeper understanding of how the body maintains homeostasis.

Monitoring body temperature and recognizing abnormal readings can help in the early detection and treatment of potential health conditions.

Overall, it is important to move away from the rigid notion of a fixed "normal" body temperature and instead consider the individual's baseline temperature and any potential factors that may affect their body temperature. By doing so, healthcare professionals can make more informed decisions regarding health assessment and treatment.


1. What is the average human body temperature? The average human body temperature is 98.6 degrees F. However, this

can vary among individuals.

2. How does body temperature vary among infants and children? A baby or child’s normal temperature varies based on age. For instance,

term newborns have a range of 97.2–99.9.

3. What is the normal body temperature range for adults?

The normal body temperature range for teens and adults is 97–99.

People over age 60 might have slightly lower temperatures.

4. How does the method of measurement affect body temperature

readings? Body temperature can differ based on where on your body you take

your temperature. For example, oral temperatures might be influenced

by room temperature and recent consumption of hot or cold liquids.

5. Is a temperature of 98.8 degrees F considered a fever? No, 98.8 falls within the normal body temperature range. Temperatures

that are 100.4 or more are considered a fever.

6. How is a fever defined in children? A fever is defined differently in children based on where the

temperature is taken. For example, a rectal temperature above 100.4 is

considered a fever for children.

7. When should one seek medical attention for a fever?

Medical attention should be sought for a fever rising above 103

degrees, especially if it's not responding to treatment.

8. What are the common symptoms of a fever?

Symptoms can include feeling warm or hot, skin being warm to touch,

a flushed face, tired eyes, and chills.

9. How can a fever be treated at home?

Some remedies include drinking plenty of fluids, taking over-the-

counter fever-reducing medications, and using a cool towel under the

arms or on the forehead.

10. What factors can influence "normal" temperature readings?

Several factors can affect body temperature, including age, sex, time

of day, and where on your body you take the temperature.


Medical Disclaimer: The information provided on this website is intended for general informational purposes only and should not be considered as a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider before making any changes to your health or wellness routine.

Do not disregard professional medical advice or delay seeking it because of something you have read on this website/blog. The content presented here is based on research and personal experiences, but individual results may vary. The information on this website is not intended to diagnose, treat, cure, or prevent any disease.


Rated 0 out of 5 stars.
No ratings yet

Add a rating
bottom of page