A certain body temperature is important for the organism to function and for all metabolic processes to take place in a regulated manner. Fluctuations in temperature are nevertheless normal, because the so-called core body temperature never remains exactly the same and is influenced by various factors.
Body temperature can also vary individually. Values between 36.3 and 37.4 degrees Celsius are called normal temperature. Values below or above, on the other hand, can indicate disease processes and also become a health problem themselves.
Hypothalamus regulates body temperature
The internal body temperature is regulated by the hypothalamus. This part of the brain constantly checks the current temperature and compares it to the "healthy" temperature of about 37 degrees Celsius. If the body’s internal temperature is too low, the hypothalamus ensures that the body generates and maintains heat. If the temperature is too high, heat is given off resp. Producing sweat that cools the skin.
Slight fluctuations in body temperature normal
Fluctuations in body temperature are normal and depend on external and internal factors. So it rises when you do sports, and is lower at night than during the day.
The following factors can influence the body temperature of humans:
- Time of day: the temperature is highest in the afternoon and can be up to one degree higher than in the morning. After that it falls off again.
- Emotions: Emotions affect body temperature. For example, in the case of stress it is usually increased.
- Physical activity: during sports or other heavy physical exertion, the temperature can rise up to 40 degrees Celsius.
- Illnesses can lead to a higher, but also to a lower body temperature.
- Hormonal fluctuations in women: One to two days after ovulation, the body temperature in women rises by about 0.5 degrees Celsius.
Small children have higher temperature
The body temperature of infants and small children is generally somewhat higher than that of adults. This is due, among other things, to the fact that their body surface is larger in relation to their body weight and their metabolism is more active. Also the temperature regulation does not work so well with them yet, besides they sweat less. For this reason they also react faster to changes with fever.
From 38 degrees Celsius one speaks of fever
Fever is actually a sensible reaction of the body. It occurs when the brain sets the body temperature higher than normal – usually to fight off pathogens like viruses or bacteria. One speaks of fever when the temperature inside the body rises to at least 38 degrees Celsius.
The following guideline values apply to body temperature in humans:
- 33,0 to 34,9 °C – hypothermia
- 35,0 to 36,2 °C – under temperature
- 36.3 to 37.4 °C – normal temperature
- 37,5 to 37,9 °C – Slightly elevated temperature
- 38.0 to 38.5 °C – slight fever
- 38.6 to 39.0 °C – Moderate fever
- 39.1 to 39.9 °C – High fever
- 40.0 to 40.9 °C – Very high fever
- 41.0 °C and higher – Extreme fever
Core body temperature is crucial
In science, a distinction is made between core body temperature and surface temperature. With the body core temperature the temperature in the vital internal organs is meant. The surface temperature, also called shell value, describes the values on the skin. It is subject to much greater fluctuations than the core body temperature due to the outside temperatures and is usually lower than it.