High temperature

When does one speak of increased temperature?

The normal body temperature in healthy people is approximately between 36.5 and 37.4 ° C. The values ​​relate to the core temperature inside the body.

An elevated (subfebrile) body temperature is when measured temperatures of 37.5-38 ° C are used.
From values ​​of 38.5 ° C there is a fever, whereby temperatures from 40 ° C are considered dangerous. Above this value, the body's own proteins can be destroyed and thus organ / tissue damage.

It should be noted that newborns and infants are referred to as fever from a core body temperature (measured rectally) of 37.8 ° C.

The core body temperature is usually measured using a clinical thermometer via the mouth (sublingual), the ear (auricular), the armpit (axillary) or the rectum (rectal).
The rectal measurement comes closest to the actual temperature inside the body.

Read more about this at: How can you measure a fever? and when should i see a doctor with a fever?


How long increased temperatures last or may last depends to a large extent on their cause and can therefore not be generalized.

In addition, one differentiates e.g. between a one-off rise in fever, fluctuations in fever during the day (remitting fever), a change from fever and fever-free phases over several days (intermittent fever), an undulating fever over several weeks (undulating fever) or a fever that recurs at regular intervals (recurrent fever ).

The duration of the fever can provide clues to the underlying cause, read more about the duration of fever on the following page: How long does a fever last?


Since increasing the core body temperature is a sensible and often necessary measure of the body to be able to combat the damaging cause better and more effectively, antipyretic agents should not necessarily be used directly in the phase of the rise in fever.
By increasing the body temperature, our organism creates a state of increased activity so that certain processes, such as the defense against pathogens, can run more efficiently.
In addition, before initiating therapy, it should be ruled out whether the subfebrile temperatures are not just physiological fluctuations. If this is not the case, the most sustainable way of reducing the temperature is to find and eliminate the cause (e.g. antibiotics in the case of bacterial infections).

However, if the temperature rises into the fever range or if the patient is significantly weakened by the increase in temperature, medically prescribed antipyretic agents should ultimately be used from a temperature of 38.5 ° C. These then primarily ensure that the body is spared.

On the one hand, antipyretic drugs with simultaneous anti-inflammatory and analgesic effects can be used. This includes the so-called non-steroidal anti-inflammatory drugs, such as ibuprofen or ASA.
Alternatively, preparations can be used which only have an analgesic effect without being able to fight inflammation (e.g. paracetamol).

In addition to taking medication, cold leg compresses or a cold washcloth on the forehead often help to dissipate the heat from the body. It is also important that you drink enough fluids to return the water lost through sweating to your body.

Also read our topic: Lower fever

These home remedies can help

The best home remedy for increased temperatures or fever is physical rest and rest. It is also very important to drink enough fluids during the feverish phase. The body loses more water through sweating during the fever. This should be offset by increased drinking.
Warm teas are well suited here, for example elderflower tea or linden blossom tea, both have a sweat-inducing effect and thus, to a certain extent, reduce fever.

Also read about this: How can you lower a fever?

The use of calf compresses is also known: for this, towels are made wet with cold water and wrapped around the lower legs, possibly also around the thighs, and left for 20-30 minutes. This can also reduce the fever.

Learn more about: Calf wraps for fever and home remedies for fever

Homeopathic remedies at elevated temperature

The following homeopathic medicines belong to the classic homeopathic remedies for increased temperature or fever, especially in the context of colds:

  • Belladonna.
  • Gelsemium (Carolina Jasmine)
  • Ferrum phosphoricum
  • Aconitum napellus (blue monkshood)

accompanying symptoms

The typical side effects of an increased temperature are mainly the following:

  • Tiredness / exhaustion
  • Muscle, joint, head and limb pain
  • Sweats / heat sensation,
  • an accelerated breathing and pulse rate
  • a dry or coated tongue
  • dry and hot skin
  • shiny eyes
  • Loss of appetite
  • Restlessness
  • Nausea and vomiting
  • Constipation symptoms

Especially in the phase of the rise in fever, there is often additional chills and a feeling of cold, as the body is still in the process of increasing the core temperature by means of muscle tremors.

The severity of the respective symptoms depends primarily on the level of the fever, with the following applies to all symptoms (except for the chills): the higher the temperature, the more pronounced the symptoms.

Elevated temperature and headache

Headaches, like body aches, are classic symptoms of flu-like infections and colds; they often even occur in combination and are accompanied by elevated temperatures or fever.

But be careful: Fever, a strong feeling of illness and severe headache, especially in children and adolescents, can sometimes be signs of far more dangerous diseases, such as meningitis.
However, other symptoms such as nausea and vomiting, neck stiffness and back pain or even impaired consciousness are usually noticed.

Please also read: Fever, dizziness and headache - what's behind it?

Elevated temperature and fatigue

If there is a rise in temperature as part of a cold or a flu-like infection, this is often accompanied by pain in the limbs and tiredness or fatigue.

The reason for this is that the body is running at full speed by fighting the pathogens and therefore needs a lot of energy to keep the immune system running. A feeling of tiredness is therefore not surprising.
The same also applies if the increased temperature occurs as part of an inflammation that is raging in the body. Here, too, there is an increased consumption of energy due to an increased body temperature. The increased temperature creates better working conditions for the immune cells fighting the inflammation.

Elevated temperature and body aches

The combination of body aches and high temperatures is well known to everyone. Classically, it occurs with flu-like infections, regardless of whether they are viral or bacterial in nature.
Just as the fever is an expression of the working immune system, the pain, especially in the arms and legs, is also a sign of the pathogen defense: during the fight against pathogens, certain messenger substances, the so-called prostaglandins, are released by various cells.
These are able to stimulate the pain receptors in the body, so that painful sensations can occur.

Elevated temperature and abdominal pain

If abdominal pain is accompanied by a fever or increased temperature, this can be a sign of a "harmless" gastrointestinal flu.

However, various inflammations of the organs in the abdomen can also hide behind it. Depending on where the maximum of the abdominal pain is concentrated, initial guesses can be made about the origin.
Classic is therefore e.g. pain in the right lower abdomen with accompanying fever, which can be a sign of inflammation of the appendix (appendicitis).

This article might also interest you: Familial Mediterranean fever

Elevated temperature and diarrhea

If high temperatures are accompanied by diarrhea and other symptoms such as stomach pain or nausea and vomiting occur, these can be signs of gastrointestinal flu (gastroenteritis).

The causes are mostly bacteria or viruses that have been ingested with food or water, more rarely food poisoning or food allergies.
Are there chronic diseases of the gastrointestinal tract, such as Crohn's disease or ulcerative colitis, high temperatures and diarrhea can also indicate an acute flare-up.

Elevated temperature and nausea

Nausea as an accompanying symptom of fever is relatively unspecific. On the one hand, this can be an expression of general malaise, e.g. occur in connection with a flu-like infection or a cold.

On the other hand, it often occurs - in combination with abdominal discomfort and diarrhea - in gastrointestinal infections. Accompaniment with a fever is very common.
However, with long-lasting and above all very high temperatures, circulation problems can also occur due to the increased loss of fluid, which in turn can lead to dizziness and nausea.

Increased temperature after an operation

Elevated temperatures after an operation, also known as postoperative fever, are not uncommon and clearly defined: One speaks of a postoperative fever whenever the patient who has recently been operated on has temperatures between the day of the operation and the 10th postoperative day of over 38 ° C.

The causes can be varied and either directly related to the operation itself or to the hospital stay in general. Infected indwelling cannulas in the veins, which are required for the administration of infusions or medication, are often a cause of fever. Urinary tract or respiratory tract infections can also occur, which are made easier by lying down for a long time and breathing more difficult due to pain.
In addition, wound infections can also cause elevated temperatures, as can infections in the abdomen after abdominal surgery. The most common pathogens then include above all bacteria, above all Staphylococcus aureus and Escherichia coli.

You might also be interested in: Fever after an operation, after-effects of anesthesia

Elevated temperature due to stress - is it possible?

Studies show that the occurrence of increased tepteratures without an infection background is possible due to stress. Permanent permanent stress, which can lead to temperature increases via mechanisms that have not yet been fully clarified, is particularly dangerous.

It is assumed that the stress leads to an increased activation of the sympathetic nervous system via the release of stress hormones such as cortisol and catecholamines from the adrenal glands. This in turn influences the temperature regulation.
Antipyretic agents tend to work less well, while calming and anxiety-relieving agents show a much better effect.

Before one can speak of fever due to stress, however, a direct connection with current psychological stress should be established and possible other causes for an increased body temperature should be excluded.

Please also read: Fever from stress or Consequences of stress

Elevated temperature after vaccination - is it normal?

The fact that there are occasionally high temperatures or fever after a vaccination is not a concern and can be viewed as a normal reaction of the body to the vaccine.
It is a general reaction of the immune system to the administered vaccine, which is initially (intentionally) recognized as harmful and combated.
As a result of this reaction, the body forms certain defensive substances (antibodies) on the one hand, and a memory for these pathogens on the other. In the event of a renewed infection with this pathogen, an immediate, efficient defense takes place.

Please also read the articles:

  • Fever in adults after vaccination
  • Fever after vaccination in the baby

Increased temperature despite antibiotics - what to do?

If the temperature remains high despite taking antibiotics, the attending physician should be consulted again.
In some cases, the antibiotic administered may not be completely effective against the suspected or specific pathogen, because they have either a natural or acquired resistance to the given active substance.
The attending physician then decides whether to give another antibiotic or a possible combination of different active ingredients that should improve the control of the pathogen in a second attempt.

Read more on the subject at: Fever despite antibiotics - what to do?

Increased temperature due to exercise

An increase in body temperature during and shortly after exercise is a normal reaction of the body to the increased stress.
With the increase in energy expenditure and oxygen consumption during exercise, a proportional increase in body temperature can also be observed. This is due to the heat production in the muscles, so that on average the temperature can rise to 37-39 ° C at normal ambient temperatures.
In a compensatory manner, the body begins to counter-regulate with sweating, increased breathing and heat emission through radiation through the skin so as not to overheat.

During top sporting performances, such as running a marathon, the temperature can rise up to 39/40 ° C.
Even after exercise, the temperature can remain elevated for some time, as the energy expenditure and heat production remain increased for a certain period of time beyond the direct sporting activity.

Elevated temperature before the period

During the menstrual cycle, the female body is subject to regulated hormonal fluctuations, which also affect the core body temperature, the so-called basal temperature.

About two days after ovulation, which takes place in the middle of the menstrual cycle, there is an increase in the corpus luteum hormone progesterone, which - in addition to many other effects - also leads to a minimal increase in the basal temperature of 0.4-0.6 ° C. So there can be no question of a correct rise in temperature. The increased basal temperature lasts until the onset of menstruation; regular basal temperature measurements are used by some women to determine the fertile days.

However, if the body temperature rises noticeably before the period, i.e. if there is a fever, another cause must be assumed. The rise in temperature can always be a sign of a parallel infection, regardless of the period or the menstrual cycle, but it is also possible that flu-like symptoms occur as part of a premenstrual syndrome.

Please also read: Pain during menstruation

Elevated temperature in the baby

Because the immune system of newborns is still untrained and only comes into contact with new pathogens in the course of development, fever is not a rare symptom in babies. It is not uncommon for babies and small children to have an average of up to six colds a year.

In newborns, a temperature of 37.8 ° C or more is referred to as fever. From a temperature of 38 ° C measured in the bottom, paediatricians recommend a visit to a doctor, as there can be both harmless and dangerous causes for small children.
Fever often occurs in the context of simple viral or bacterial infections of the upper respiratory tract or the ears, as well as during teething and gastrointestinal infections.

But even with typical children's diseases, such as febrile convulsions, three-day fever, mumps, measles, rubella, scarlet fever, chickenpox or hand, foot and mouth disease, elevated temperatures can occur.
Diseases such as bone and joint inflammation or meningitis are less common, but all the more dangerous. A special feature of babies, however, is that many of the diseases mentioned can also occur without a fever. Therefore, in any case, attention should be paid to other abnormalities such as reluctance to drink, sluggishness and sluggishness and changes in behavior of any kind.

Please also read: Fever suppositories (for babies and toddlers), What to do if your baby has a fever?

Elevated temperature in the teething baby

It is not uncommon that teething in the offspring can sometimes be accompanied by a short-term rise in temperature. The little ones often show symptoms in parallel, such as pain, swollen and reddened gums, reddened cheeks, restlessness and sleep disorders as well as abdominal pain and diarrhea.

If the elevated temperature lasts longer or if the temperature rises unusually high, a doctor should still be consulted urgently, as other diseases can also hide behind the fever.

Elevated temperature during pregnancy

Increased temperatures during pregnancy are not so surprising, since the mother is in a physical state of emergency: with the unborn child, there is a "foreign organism" in the womb.
This makes it essential that the mother's immune system is suppressed to a certain extent in order to avoid the defense against the "foreign".
That is why flu-like infections are not uncommon at the beginning of pregnancy. A fever alone or in combination with symptoms of a cold is therefore not bad at first.

It becomes dangerous when the elevated temperatures result in abdominal pain or even premature rupture of the bladder.
At this point at the latest, a doctor should be consulted immediately.

Other infections that can be associated with fever, such as rubella, toxoplasmosis, hepatitis or herpes viruses, are also undesirable and dangerous for the unborn child.

Increased temperature in the puerperium

Elevated temperatures in the puerperium, also known as puerperal fever or puerperal fever, are an expression of an infection of the female genital organs after childbirth, usually caused by bacteria penetrating the birth wound.

Bacteria usually rise from the vagina into the uterus and trigger inflammation there or even on the fallopian tubes and ovaries. In addition to increased temperatures, there is also pressure pain in the lower abdomen, malodorous weekly flow and circulatory problems.
This disease is favored by vaginal deliveries, caesarean sections, premature rupture of the bladder, the remaining patency remnants or a congestion of the weekly flow.


An increased body temperature can have a variety of causes.

  • Cause of postoperative fever:
    In many cases, after major surgical interventions, there is a rise in temperature in the first 10 days after the operation. This is due to the physiological reaction of the body to the body structures injured by the operation and the foreign body material (e.g. wires, threads, etc.) that may be used. However, if the temperature rises into the fever range, this can also be an indication of existing postoperative infections (e.g. wound infections).
  • Environmental influences:
    Very high outside temperatures and direct, strong sunlight on the body can also lead to an increased temperature. This can even trigger a life-threatening heat stroke (overheating of the body to over 40 ° C with subsequent brain edema or brain damage).
  • Infections:
    Of course, bacterial or viral infections are always possible, in which the body supports the immune system through increased temperatures and makes the pathogen defense more efficient. As a rule, the fever is higher in bacterial infections than in viral ones.
  • Allergies:
    However, allergic reactions (e.g. hay fever, pollen allergy, reaction to food or medication) can also lead to an increased temperature.
  • Immune system disorders:
    In the same way, rheumatic diseases and autoimmune diseases, in which the immune system recognizes the body's own structures as foreign and attacks them, can have fever as an accompanying symptom.
  • Cause stress:
    Other circumstances that can cause an increased body temperature are increased stress or the use of certain drugs (e.g. antibiotics such as ampicillin, cephalosporins, vancomycin; tricyclic antidepressants, atropine, etc.).
  • Tumor as a cause:
    A very rare cause of an elevated temperature over a long period of time can be an existing tumor. If the increased temperature also occurs together with unwanted weight loss and night sweats (so-called B symptoms in tumor diseases), a general check-up for possible tumor diseases makes sense.
  • unclear cause:
    If there are high temperatures or even a fever above 38.5 ° C for a period of at least 3 weeks without any cause being found by the medical diagnosis, then one speaks of a fever of unclear origin.

It is noticeable that toddlers are much more likely to have elevated temperatures or a fever than adults. This is due, among other things, to the fact that the immune system of the little ones is not yet fully developed and therefore bacteria or viruses lead to infections much more frequently. However, this does not mean that every increase in temperature in the child is synonymous with an infection (e.g. otitis media, flu-like infection, gastrointestinal infections, etc.).
For example, temperature rises or a fever can occur if the teeth come out of the offspring or simply because they romp around a lot or put on warm clothes.

You might also be interested in the following topic: Causes of fever

Physiological causes for slightly elevated temperatures

One of the physiological causes of slight temperature fluctuations or increases are differences in the body's metabolic activity during the day.
As a result, the core body temperature is physiologically lower at night than it is during the day, in the second half of the night and in the morning it reaches its lowest point and in the afternoon or early evening it reaches its maximum value.
Depending on the point in time of the temperature measurements, normal temperature fluctuations can therefore be interpreted as an increased temperature.

Likewise, the temperatures can vary slightly from one another in different places within the body. This means that the measured values ​​can deviate from each other if the temperature is not always measured at the same point.

One of the physiological body temperature fluctuations in women is the slightly elevated temperature in the second half of the cycle shortly after ovulation, which persists until the beginning of the next period.
This is a difference of approx. 0.2-0.5 ° C (e.g. from 36.5 to 37 ° C), which is caused by the increase in the hormone progesterone.

The same applies in the case of an existing pregnancy, in which, due to the permanent excess production of progesterone, there is a constant temperature increase of up to 0.5 ° C.
If, however, the temperature rises to a higher degree in the course of the pregnancy, even leading to a fever, it is advisable to consult your gynecologist immediately in order to rule out possible pregnancy complications.

Further information on this topic can be found at: Fever during pregnancy


A clinical thermometer is usually used to measure whether the body temperature is elevated. The accuracy of the measurement depends not only on the device properties but also on the location of the measurement.

  • The temperature measurement in the buttocks (rectal) is considered to be the most accurate as it comes closest to the actual temperature inside the body.
  • The measurement in the mouth, in which the clinical thermometer is placed under the tongue (sublingual) and the lips must be closed, is also quite accurate, but usually deviates by up to 0.3 ° C from the more uncomfortable rectal measurement. Previously consumed hot or cold food or drinks can also falsify the sublingual measurement.
  • Furthermore, the core body temperature can also be measured under the armpit (axillary), whereby this method is considered to be the most pleasant and widely used, but also the most inaccurate (up to 0.5 ° C deviation from rectal measurements).
  • Finally, increased temperatures can also be measured in the ear using infrared waves, but here too, inflammation or blockage of the ear canal with ear wax can cause incorrectly low measured values.

Read more on the topic: How can you measure a fever?

If, after the correct measurement, there is actually an increased body temperature, the cause must be found.
As a rule, the attending physician first examines the patient physically for further signs of infection or inflammation, for example, and inquires about previous stays abroad.

A blood, urine or stool sample can also be taken for further clarification in order to check for inflammatory and / or bacterial infections.