The normal human body temperature is between 36.5 and 37.4 °C. However, the temperature varies from person to person and can be sometimes higher and sometimes lower depending on the time of day and physical activity. In this article, we will look at body temperature in adults, children and the elderly.
What is the normal body temperature in humans?
Body temperature in humans usually fluctuates. There are many reasons for this, such as on which part of the body the temperature was measured. In the armpit, temperatures are usually lower compared to a rectal measurement. Other reasons for varying temperatures are:
– Age
– gender
– Time of day – temperature is usually lowest in the morning
– Nutrition and fluid intake
– exercise
– Menstruation
– Diseases or other health conditions
Normal body temperature by measurement variant and age.
The following table provides an overview of the measurement variants and age differences in body temperature in humans.
| Type | 0 – 2 Years | 3 – 10 Years | 11 – 65 Years | 65+ Years |
| Oral | 35,5 – 37,5 °C | 35,5 – 37,5 °C | 36,4 – 37,6 °C | 35,8 – 36,9 °C |
| Rectal | 36,6 – 38,0 °C | 36,6 – 38,0°C | 37,0 – 38,1 °C | 36,2 – 37,3 °C |
| Armpit | 34,7 – 37,3 °C | 35,9 – 36,7 °C | 35,2 – 36,9 °C | 35,6 – 38,0 °C |
| Ear | 36,4 – 38,0 °C | 36,1 – 37,8 °C | 35,9 – 37,6 °C | 35,8 – 37,5 °C |
| Inner measurement | 36,3 – 37,7 °C | 36,3 – 37,7 °C | 36,7 – 37,8 °C | 35,8 – 37,1 °C |
Body temperature is controlled by the hypothalamus, which continuously adjusts temperature by comparing the current temperature to the normal value of about 37 degrees Celsius. If the temperature is too low, the hypothalamus sends signals so that the body produces enough heat for the body. If the temperature is too high, the body starts sweating to cool the skin.
Normal body temperature adults
The normal body temperature of an adult is about 37 degrees Celsius when measured in the ear. Other types of measurements, as seen in the table above, give slightly different values. The stages of fever in adults look as follows:
– 38.0 °C: fever
– 39.5 °C: high fever
– 41.0 °C: extremely high fever
There are differences in temperature from person to person, including between men and women.
Temperature difference between men and women
There are differences in body temperatures between men and women simply because of hormonal differences. On average, women have a higher body temperature. In addition, women experience a temperature increase of about 0.5 degrees Celsius one to two days after ovulation.
Apart from the body temperature itself, the temperature of the skin also varies. The skin temperature on women’s hands is usually lower than that of men. Some studies speak of a difference of up to 2.8 °C. The reason for this has not yet been fully researched, but it is assumed that the difference in temperature occurs due to differences in height, weight and body proportions. In addition, men can generate heat better due to the higher muscle mass, as these are constantly supplied with blood and thus generate heat non-stop. Besides that, the ratio of the surface area of the body with the volume of the body is less practical. A woman’s body is smaller and radiates more heat. Another reason is the skin itself. Women generally have thinner epidermis than men, so the skin cools faster.
There are also differences in blood circulation. Estrogen dilates blood vessels in women, so blood flow increases and warms up the feet and hands. In this process, however, a lot of heat is released into the environment. In order to protect the internal organs, a woman’s body shuts down the blood flow from 15 °C onwards. In the process, the ears, nose, feet and the entire skin surface cool down.
Normal body temperature in the elderly
As the immune system of older people becomes less and less effective, fewer messenger substances are produced by the immune system. Without these messengers, the temperature remains lower. This can end up being quite dangerous, as older people can only rarely get a fever and infections are thus only detected late. In order to diagnose fever, the following criteria must occur:
– With a single oral measurement, the temperature is higher than 37.8 °C
– Multiple oral measurements are higher than 37.2 °C or multiple rectal temperatures are higher than 37.5 °C
– Basal temperature increases by 1.1 °C
Normal body temperature children
In children, normal body temperature depends on age, as shown in the table below. The temperatures are divided into 0 – 2 and 3 – 10 years. From the age of eleven, one can orientate oneself on the data of the adults:
| Type | 0 – 2 Years | 3 – 10 Years |
| Oral | 35,5 – 37,5 °C | 35,5 – 37,5 °C |
| Rectal | 36,6 – 38,0 °C | 36,6 – 38,0°C |
| Armpit | 34,7 – 37,3 °C | 35,9 – 36,7 °C |
| Ear | 36,4 – 38,0 °C | 36,1 – 37,8 °C |
| Inner measurement | 36,3 – 37,7 °C | 36,3 – 37,7 °C |
The temperature of children also fluctuates throughout the day. Generally, the temperature is lowest in the morning. An exception are particularly active children. In this case, temperatures are especially elevated in the evening.
A temperature of 38.5 °C or higher in children is called a fever. You can find more information in the article Fever in babies, toddlers and children.
Normal body temperature babies
Usually, babies have a higher body temperature. This is because babies have a larger body surface area in relation to their weight. In addition, the metabolism of babies is much more active and thus continues to produce heat.
Newborns have an average body temperature of 37.5 °C. If the child starts teething, the temperature may also be slightly elevated.
Depending on the type of measurement, the body temperature can fluctuate greatly:
| Type | 0 – 2 Jahre |
| Oral | 35,5 – 37,5 °C |
| Rectal | 36,6 – 38,0 °C |
| Armpit | 34,7 – 37,3 °C |
| Ear | 36,4 – 38,0 °C |
| Inner measurement | 36,3 – 37,7 °C |
How to measure body temperature correctly
Since there are many different thermometers to measure body temperature, it can be confusing which method of measurement to use now. Usually it depends on the age of the person. Below you can see a small overview of the age categories as well as their appropriate examination method:
| Alter | Methode |
| 0 – 3 Months | Rectal |
| 3 Months – 3 Years | Rectal Ear Armpit |
| 4 – 5 Years | Rectal Oral Ear Armpit |
| ab 5 Years | Oral Ear Armpit |
If a temperature is unusually high or low, it helps to wait five to ten minutes and then measure again. It is also helpful to use a different measurement method to check the temperature. All measurement methods and instructions on how to take a fever correctly can be found in the article: Taking a Fever
Are slight fluctuations in body temperature normal?
In short, yes! It is completely normal and also healthy for the body temperature to change throughout the day. The temperature can fluctuate between 0.5 °C and 1.0 °C. In the morning – and especially between 02:00 and 04:00 in the morning, the temperature is at its lowest because the body is resting in this state and needs to generate less heat. This is different between 16:00 and 18:00. Here, due to increased physical activity throughout the day, the temperature is the highest. In addition, the temperatures in our environment as well as sporting activities influence the body temperature.
Up to 5% of the population also have body temperatures that are not in the normal range. This may be due to the metabolism of many, for example. A slow metabolism means that one is more likely to have a lower body temperature. A higher metabolism also means a higher body temperature. Metabolism is influenced by genetic makeup, lifestyle, age and environment.
Symptoms of fever
As a rule, one speaks of fever only at 38 °C. More information can be found in the article “When does a fever start?
Fever usually occurs due to infection, inflammation or non-infectious diseases. Typical symptoms of fever, in addition to increased temperature, include the following:
- Loss of appetite
- Chills
- Headache
- Muscle pain
- Sweating
- Feeling of dullness
When is the body temperature too low?
The ideal body temperature for adults is 36 – 37 °C. However, if this drops below 35 °C, hypothermia occurs. The body loses heat and does not manage to generate it fast enough. In the worst case, these are life-threatening, as the organs can no longer be supplied properly. Read our article Hypothermia for everything you need to know about body temperatures that are too low.
Summary
The ideal body temperature for adults is about 37 °C. However, this ideal temperature depends on the age, sex, health and activity of the body. It is also important that the temperature fluctuates throughout the day. This is perfectly healthy and initially no cause for concern. However, a temperature above 38 °C signals a fever and should be monitored more closely. If the temperature is particularly high or low, you should definitely consult a doctor.
Babies have an elevated body temperature compared to adults and even a small increase in this can indicate a serious infection.
It is also important to remember that temperature also varies with different methods of measurement. Rectal measurements are higher than measurements in the mouth and measurements in the armpits are generally lower.
Sources:
- How is body temperature regulated and what is fever?, www.ncbi.nlm.nih.gov
- Time to redefine normal body temperature?, www.health.harvard.edu
- Body Temperature and How It Differs for Men and Women, www.simplysupplements.co.uk
Ben Lesser ist einer der gefragtesten Experten im Bereich Gesundheit, Fitness und Medizin. Seine Artikel überzeugen durch einzigartige Recherchearbeiten sowie praxiserprobte Fähigkeiten. Er ist freiberuflicher medizinischer Autor, der sich auf die Erstellung von Inhalten zur Verbesserung des öffentlichen Bewusstseins für Gesundheitsthemen spezialisiert hat. Wir haben die Ehre dass Ben exklusiv und ausschließlich für Dualdiagnosis.org Texte verfasst.