What constitutes a dangerous body temperature in adults. How to recognize high-grade fevers. When should you worry about a fever. What are the causes of fevers without other symptoms. Is 98.6°F still considered the normal body temperature.

Understanding Fever: What It Is and Why We Get It

Fever is a common bodily response that often raises concerns, especially when it occurs unexpectedly. But what exactly is a fever, and why does our body produce it? Let’s delve into the details.

A fever is defined as an elevated body temperature of 100.4°F (38°C) or higher. It’s the body’s natural defense mechanism against infections, working to create an inhospitable environment for pathogens. By raising the body’s temperature, fever essentially attempts to “kill the germ” causing the infection.

Interestingly, adults can develop a fever without exhibiting any other symptoms. In such cases, the underlying cause may remain unidentified, even after medical examination. Viral infections are common culprits behind fevers, including:

• COVID-19
• Common cold or flu
• Airway infections like bronchitis
• Gastrointestinal viruses

These viral infections often resolve on their own within a few days, which is why you might hear healthcare providers use the term “viral” as an explanation for unexplained fevers.

High-Grade Fevers in Adults: When Should You Be Concerned?

While fever itself is a natural response, certain temperature thresholds warrant more attention. In adults, a high-grade fever is considered to be 103°F (39.4°C) or higher. But when should you really start to worry about a fever?

Here are some situations where seeking medical attention for a fever is advisable:

1. Your temperature remains high despite taking over-the-counter fever reducers like Tylenol or Advil
2. The fever persists for several days or keeps recurring
3. You live in an area with active COVID-19 cases
4. You have underlying health conditions such as diabetes, heart disease, cancer, lupus, or sickle cell anemia

Additionally, immediate medical attention is crucial if you have a fever and:

• Are pregnant
• Have recently returned from overseas travel
• Are prone to frequent infections
• Are undergoing chemotherapy (seek help if the fever lasts more than an hour)
• Have recently been bitten by a tick

The Myth of 98.6°F: Redefining Normal Body Temperature

For centuries, 98.6°F (37°C) has been considered the benchmark for normal body temperature. However, recent research suggests that this long-held belief might need revision. Is 98.6°F still considered the standard for normal body temperature?

The answer is both yes and no. While 98.6°F remains a reference point, the reality is that normal body temperature exists within a broader range, typically between 97°F to 99°F (36.1°C to 37.2°C). This shift in understanding stems from recent studies indicating a general decline in average body temperatures over time.

Several factors may contribute to this trend:

• Lower metabolic rates in modern populations
• Reduced rates of infection due to improved hygiene and medical care
• More accurate thermometers providing precise measurements

This evolving understanding of body temperature norms underscores the importance of considering individual variations and overall health context when interpreting temperature readings.

Fever in the Context of COVID-19: What You Need to Know

In the current global health landscape, fever takes on added significance due to the ongoing COVID-19 pandemic. Can a fever be a sign of a “breakthrough” COVID-19 case in fully vaccinated individuals?

While breakthrough cases of COVID-19 in fully vaccinated people have been reported, they are relatively rare. When they do occur, symptoms tend to be milder compared to those in unvaccinated individuals. This includes fever, which may be less severe or absent in breakthrough cases.

However, if you develop a high-grade fever and are not fully vaccinated against COVID-19, it’s crucial to contact your healthcare provider immediately. They can provide guidance on testing, isolation, and necessary medical interventions.

The Art of Accurate Temperature Measurement

Accurate temperature measurement is crucial for proper fever assessment and management. How can you ensure you’re taking your temperature correctly?

The most reliable method for adults is oral temperature measurement. To get an accurate reading:

1. Wait at least 30 minutes after eating or drinking anything hot or cold
2. Place the thermometer under your tongue
3. Keep your mouth closed around the thermometer
4. Wait until the thermometer signals it has completed its reading

Remember, different measurement methods (rectal, armpit, ear, forehead, mouth) can yield slightly different results. Always use the same method consistently for the most accurate comparisons over time.

Fever Management: When to Let It Run Its Course

While fever can be concerning, it’s important to remember that it’s often a beneficial response. As the saying goes, “Don’t fear the fever.” In many cases, a fever is your body’s first line of defense against infection.

For generally healthy adults, allowing a low-grade fever to run its course can be beneficial. This natural process helps stimulate the immune system and create an environment less favorable for pathogens.

However, there are instances when intervention is necessary. Consider treating a fever if:

• It’s causing significant discomfort
• It’s interfering with sleep or daily activities
• You have a pre-existing medical condition that makes fever risky

In these cases, over-the-counter fever reducers like acetaminophen or ibuprofen can help manage symptoms. Always follow the recommended dosage and consult with a healthcare provider if you’re unsure.

Special Considerations: Fever in Vulnerable Populations

While this article focuses primarily on fever in adults, it’s crucial to recognize that certain populations require special attention when it comes to fever management. Who are these vulnerable groups, and why do they need extra care?

Elderly Individuals

Older adults, particularly those over 65, may not exhibit typical fever responses. Their baseline temperature might be lower, and they may not develop high fevers even when seriously ill. Any change in an elderly person’s normal temperature or behavior warrants medical attention.

Immunocompromised Individuals

People with weakened immune systems, such as those undergoing chemotherapy or living with HIV/AIDS, may not be able to mount a proper fever response. Even a slight temperature elevation in these individuals could signal a serious infection requiring immediate medical intervention.

Pregnant Women

Fever during pregnancy can potentially affect fetal development, especially in the first trimester. Pregnant women with fever should consult their healthcare provider promptly for appropriate management and monitoring.

For these vulnerable populations, it’s always better to err on the side of caution and seek medical advice when a fever occurs, regardless of its severity.

Beyond Temperature: Other Signs of Serious Illness

While fever is an important indicator of illness, it’s not the only factor to consider when assessing your health. What other symptoms might suggest a more serious condition requiring medical attention?

Be alert for the following signs accompanying a fever:

• Severe headache or neck stiffness
• Confusion or altered mental state
• Persistent vomiting or diarrhea
• Difficulty breathing or chest pain
• Unexplained rash or bruising
• Severe abdominal pain

The presence of these symptoms, especially in combination with a high fever, warrants immediate medical evaluation. They could indicate more severe conditions such as meningitis, sepsis, or other serious infections that require prompt treatment.

Remember, your body often provides signals beyond just temperature elevation when something is seriously wrong. Paying attention to these additional symptoms can help you make informed decisions about seeking medical care.

The Role of Hydration in Fever Management

Proper hydration plays a crucial role in managing fevers and supporting overall health during illness. Why is staying hydrated so important when you have a fever?

Fever can lead to increased fluid loss through sweating and rapid breathing. This dehydration can exacerbate symptoms and potentially lead to complications. Adequate fluid intake helps:

• Regulate body temperature
• Support immune function
• Flush out toxins
• Prevent dehydration-related complications

Water is usually the best choice for hydration, but clear broths, herbal teas, and electrolyte solutions can also be beneficial. Avoid caffeine and alcohol, as these can contribute to dehydration.

If you’re having trouble keeping fluids down due to nausea or vomiting, try taking small sips frequently rather than large amounts at once. Ice chips or frozen fruit pieces can also help increase fluid intake while providing comfort.

The Impact of Environment on Body Temperature

While internal factors like infections are common causes of fever, external environmental conditions can also influence body temperature. How does your surroundings affect your body heat?

Several environmental factors can impact body temperature:

• Ambient temperature: Hot environments can raise body temperature, while cold environments can lower it
• Humidity: High humidity can interfere with the body’s ability to cool itself through sweating
• Sun exposure: Direct sunlight can increase body temperature, potentially leading to heat-related illnesses
• Physical activity: Intense exercise, especially in hot conditions, can significantly raise body temperature

It’s important to consider these factors when assessing fever. For instance, a slightly elevated temperature after spending time in a hot environment or exercising might not necessarily indicate illness.

Conversely, being in an air-conditioned environment might mask a fever, especially in older adults who are more susceptible to hypothermia. Always consider the context when interpreting body temperature readings.

Fever and Sleep: Balancing Rest and Recovery

Sleep plays a vital role in recovery from illness, but fever can often disrupt normal sleep patterns. How can you balance the need for rest with the discomfort of a fever?

Here are some strategies to promote better sleep during a fever:

• Keep the room cool but not cold
• Use lightweight, breathable bedding
• Stay hydrated, but avoid large amounts of fluid right before bed
• Consider using a cool compress on your forehead or wrists
• Take fever-reducing medication if discomfort is severe, following proper dosage guidelines

Remember, while sleep is important for recovery, don’t force yourself to stay in bed if you’re uncomfortable. Sometimes, brief periods of light activity can help alleviate fever-related discomfort and promote better rest afterwards.

If fever consistently interferes with sleep for several nights, consult your healthcare provider. Prolonged sleep disturbance can hinder recovery and may indicate a need for further evaluation.

The Future of Fever Monitoring: Wearable Technology

As technology continues to advance, new tools are emerging for monitoring body temperature and detecting fevers. How might wearable devices change the landscape of fever detection and management?

Wearable temperature sensors offer several potential benefits:

• Continuous monitoring: Allows for real-time tracking of temperature fluctuations
• Early detection: May identify fever onset before other symptoms appear
• Remote monitoring: Enables healthcare providers to track patients’ temperatures from afar
• Data integration: Can combine temperature data with other health metrics for comprehensive analysis

While these technologies show promise, it’s important to note that they are still evolving. Traditional methods of temperature measurement remain the gold standard for now. Always consult with healthcare professionals for accurate diagnosis and treatment plans.

As wearable fever detection technology advances, it may become an invaluable tool in both personal health management and public health strategies, potentially aiding in early detection of infectious disease outbreaks.

Cultural Perspectives on Fever and Its Management

Attitudes towards fever and its treatment can vary significantly across different cultures. How do cultural beliefs influence fever management practices around the world?

Various cultural approaches to fever include:

• Traditional Chinese Medicine: Views fever as a sign of imbalance in the body’s energy flow
• Ayurvedic Medicine: Considers fever a purification process and may recommend specific diets or herbs
• Some African cultures: Believe in “sweating out” a fever through heat exposure or vigorous exercise
• Western medicine: Focuses on symptomatic relief and identifying underlying causes

While cultural practices can offer comfort and align with personal beliefs, it’s crucial to approach fever management with a balance of cultural sensitivity and evidence-based medical knowledge. Always consult with healthcare professionals, especially for high or persistent fevers.

Understanding these diverse perspectives can help healthcare providers deliver more culturally competent care and improve patient outcomes across different populations.

Fever & Temperature In Adults: When To Worry

Karen Justiniano, DO, MS, Stamford Health Medical Group

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A friend of mine whose father is 70 years old told me her story. It went something like this:

“My father never gets fevers. Out of nowhere the other day, he developed a 103 temperature with no other symptoms. He is also fully vaccinated against COVID-19. My mother brought him to the emergency room. Did she do the right thing, or would he likely have been fine if he stayed home and let the fever run its course?”

As a physician who cares for a variety of people with a variety of conditions, I have to say of course she did the right thing! When in doubt or when concerned, seeking medical attention is the smart thing to do.

But the longer answer is a little more complicated than that. It all starts with breaking down the purpose of a fever, and when you should truly worry. Please note—fevers in infants or young children are sometimes a different story—what you are about to read relates to adults only.

What is a fever and why do we get them, and sometimes with no other symptoms?

Fever is an elevated body temperature which means your temperature is 100.4 degree F or higher. A fever is the body’s way of fighting an infection by naturally raising your body’s temperature to “kill the germ.” The medical community likes to say that fever is a “good thing,” in most cases.

And yes, it’s completely possible for adults to develop a fever with no other symptoms, and for doctors to never truly find the cause. Viral Infections can commonly cause fevers, and such infections include COVID-19, cold or the flu, airway infection like bronchitis, or the classic stomach bug.

That’s why you often hear the word “viral” as an explanation because these types of infections often go away on their own after a few days.

What is considered a high fever in adults?

A high-grade fever in adults is 103 degrees F or higher.

Is it possible that a fever could be a sign of a “breakthrough case” of COVID-19 even if the person is fully vaccinated?

Yes, but not highly likely. Breakthrough cases of COVID-19 in fully vaccinated people have been reported, but symptoms tend to be milder than in non-vaccinated people, including fever.

First, make sure you are taking your temperature the right way. Taking your temperature by mouth is the most accurate method, and wait at least 30 minutes after you eat or drink anything hot or cold. Get medical attention for your fever if:

• Your temperature is high and has not gone down after taking Tylenol or Advil
• Your temperature lasts several days or keeps coming back
• You live in an area where people have COVID-19
• You have serious health conditions like diabetes, heart disease, cancer, lupus, or sickle cell anemia. (Non-infections like these can cause fever as well.)

You should also seek medial attention if you have a fever and you:

• Are pregnant
• Recently returned from travel overseas
• Get infections often
• Are on chemotherapy, in which case you should seek medical attention immediately if the fever lasts for more than one hour.
• Have recently been bitten by a tick

Is 98.6 still considered “normal” body temperature?

Yes and no. You’ve probably always heard that the average body temperature is 98.6, but the truth is there’s a much wider range—from about 97 to 99 degrees F.

So why is 98.6 suddenly a myth after all these centuries? Research suggests body temperatures are falling overall. Doctors have a few ideas about why this is, including lower metabolic rates, lower rates of infection and more advanced thermometers.

A couple of helpful reminders:

1. As the saying goes, “Don’t fear the fever.” A fever is your body’s first line of defense in fighting off an infection.
2. If you are not fully vaccinated against COVID-19, and have developed a high-grade fever, please call your doctor right away.

Fever (High Temperature) In Kids (for Parents)

All kids get a fever from time to time. Usually, a fever isn’t dangerous or bad for kids. It can even be a good thing because it can help the immune system fight infection.

Still, parents might be unsure about how to handle a fever at home and when to call the doctor. Here are some tips.

What Is a Fever?

In general, a fever means the body’s temperature is 100.4°F (38°C) or higher. Different ways of measuring a temperature — rectal, armpit, ear, forehead, mouth — get a slightly different number, so the number that means a child has a fever is a little different too. 

What Causes Fevers?

Fevers in kids are usually caused by an infection. A fever helps the body by stimulating the immune system to fight the infection. Doctors also think the higher temperature makes it harder for the germs to grow.

A few other reasons kids can have a fever:

Overdressing: Infants, especially newborns, may get fevers if they’re overdressed, wrapped in a blanket, or in a hot environment because they don’t regulate their body temperature as well as older kids. But because fevers in newborns can be a sign of a serious infection, even infants who are overdressed must be checked by a doctor if they have a fever.

Immunizations: Babies and kids sometimes get a mild fever that lasts about a day after getting vaccinated.

A child who is teething might have a slight rise in body temperature, but it’s probably not the cause if the temperature is higher than 100°F (37.8°C).

When Is a Fever a Sign of Something Serious?

In most healthy kids who are acting well, a fever isn’t serious.

But a fever can be serious for:

• Infants younger than 3 months: If an infant younger than 3 months has a rectal temperature of 100.4°F (38°C) or higher, call your doctor or go to the emergency department right away. 
• Kids with some health conditions: If your child has an ongoing health issue, make sure you know if the doctor should be called for fever.

A fever is probably not serious if your child is 3 months or older and:

• is still interested in playing
• is drinking well
• is alert and smiling
• has a normal skin color
• looks well when their temperature comes down

Don’t worry too much about a child with a fever who doesn’t want to eat. This is common with infections that cause fever. For kids who still drink and urinate (pee) normally, not eating as much as usual is OK.

What Are the Signs of a Fever?

Kids with a fever might:

• feel warm
• act differently (they might be fussy or cranky, or quieter than usual)
• breathe a little faster or have a faster heart rate than normal
• have a headache
• have chills or sweating
• have red or flushed skin

For any of these signs, take your child’s temperature to know if they really have a fever.

If your child feels warm or is acting unwell, use a digital thermometer to confirm a fever. Different ways of taking the temperature are more accurate than others at measuring the true body temperature.

The best way to take a temperature:

• for kids 3 years old and younger: a rectal temperature
• for kids 4 or older who can cooperate: an oral temperature (by mouth)
• for any age: under the armpit (axillary) and temporal artery (forehead) are easiest but less accurate. Tympanic (in the ear) is OK for kids 6 months and older.

It’s a fever when a child’s temperature is at or above one of these levels:

• rectal (in the bottom), tympanic (in the ear), or temporal artery (across the forehead): 100.4°F (38°C)
• oral (in the mouth): 100°F (37.8°C)
• axillary (under the arm): 99°F (37.2°C)

How Can I Help My Child Feel Better?

No treatment is needed if a child is still playing and drinking normally and doesn’t have pain. 

Treating a fever with medicine isn’t needed if a child is still playing and drinking normally and doesn’t have pain. Give medicine only when a fever causes a child discomfort or keeps them from drinking.

While kids have a fever, keep an eye on them, help them to rest, and keep offering fluids to drink. They need to drink a little extra to make up for the fluids they lose from sweating.

Home Care Measures

Medicines

If your child is uncomfortable from a fever or not drinking fluids well, you can give one of these medicines:

• acetaminophen (such as Tylenol or a store brand)
  or
• ibuprofen (such as Advil, Motrin, or a store brand). Do not give to children under 6 months old.

Follow the package directions for how much to give and how often. If you don’t know the recommended dose or your child is younger than 2 years old, call the doctor to find out what to use and how much to give.

• If your child has any medical problems, check with the doctor to see which medicine to use.
• Unless instructed to by a doctor, never give aspirin to a child. Such use is linked to Reye syndrome, a rare but serious illness.

Do not give any medicine for fever to infants younger than 3 months old unless instructed to by a doctor.

Staying Comfortable

If your child has a fever:

• Have them wear lightweight clothing and stay covered with a light sheet or blanket. Heavy clothes and blankets can keep the body from cooling, which can make your child uncomfortable.
• Keep the room at a comfortable temperature — not too hot or too cold.
• Make sure they get plenty of rest. Staying in bed all day isn’t necessary, but a sick child should take it easy.
• They should stay home from school or childcare until their temperature has been normal for 24 hours.

Lukewarm sponge baths to lower a fever generally are not recommended. In fact, sponge baths can make kids uncomfortable from shivering. Never use rubbing alcohol (it can cause poisoning when absorbed through the skin) or ice packs/cold baths (they can cause chills that can raise body temperature).

Food and Drinks

Offer plenty of fluids to avoid dehydration because fevers make kids lose fluids faster than usual. Oral rehydration solutions (like Pedialyle, Enfalyte, or store brands) are a good choice. You also can give water, soup, ice pops, and flavored gelatin. Avoid drinks with caffeine, including colas and tea, which can make dehydration worse by making kids pee more often.

Let kids eat what they want (in reasonable amounts), but don’t force it if they don’t feel like eating much.

When Should I Call the Doctor?

The temperature that should trigger a call to the doctor depends on a child’s age, the illness, and whether they have other symptoms. You might ask if your doctor has specific guidelines on when to call about a fever.

In general, call the doctor if your child is:

• younger than 3 months old with a rectal temperature of 100.4°F (38°C) or higher
• 3 months or older with a temperature higher than 102.2°F (39°C)
• any age but has a health problem like cancer or sickle cell disease and has a fever

Also call if a child 3 months or older has a fever and:

• refuses fluids or seems too ill to drink enough
• has lasting diarrhea or repeated vomiting
• has any signs of dehydration (peeing less than usual, not having tears when crying, less alert and less active than usual)
• has a specific complaint (like a sore throat or earache)
• still has a fever after 2–3 days
• has a rash
• has pain while peeing

Get emergency care if your child shows any of these signs:

• crying that won’t stop
• extreme irritability or fussiness
• sluggishness and trouble waking up
• a rash or purple spots that look like bruises on the skin (that were not there before your child got sick)
• blue lips, tongue, or nails
• in an infant, the soft spot on the head seems to be bulging out or sunken in
• stiff neck
• severe headache
• limpness or refusal to move
• trouble breathing that doesn’t get better when the nose is cleared
• leaning forward and drooling
• seizure
• moderate to severe belly pain

What Else Should I Know?

All kids get fevers, and in most cases they’re back to normal within a few days. For older babies and kids, the way they act can be more important than the reading on your thermometer. Everyone gets a little cranky when they have a fever. This is normal and should be expected.

But if you’re ever in doubt about what to do or what a fever might mean, or if your child is acting ill in a way that concerns you even with no fever, always call your doctor for advice.

Medically reviewed by: Melanie L. Pitone, MD

Date reviewed: November 2022

What body temperature is considered normal?

Body temperature is individual for each person and depends on different characteristics of the body, however, in some cases, a low or high temperature may indicate serious problems. This was told to Izvestiya by the head of the polyclinic department of the MEDSI Clinical Hospital No. 1 in Otradnoye, a therapist-oncologist Natalia Tolstykh.

According to the specialist, body temperature can be influenced by such indicators as metabolic characteristics, the work of the endocrine glands or the autonomic nervous system. At the same time, for each person during the day, the temperature fluctuates within small limits, remaining in the range from 35.5 to 37.2 degrees for a healthy person.

The temperature may also vary depending on the activity (with high activity, the temperature may rise slightly) and the time of day. Normal daily temperature fluctuations are 0.5–0.7 degrees. When a person falls asleep, all processes in the body slow down and the body temperature drops slightly, getting closer to 35-36 degrees, Tolstykh explained.

“It is important to understand that lower (compared to the population norm) body temperature, that is, less than 35.5 degrees, may be an individual feature of some people, and does not always indicate the presence of diseases. Low body temperature, or the so-called hypothermia (below 35.2 degrees), can be caused by hypothermia, intoxication, problems with the endocrine system (reduced thyroid function – hypothyroidism, or adrenal insufficiency) “- said the oncologist.

Hypothermia also occurs in severe infections among the elderly, with hypothermia. Often the temperature can be lowered within a few days after a person has had an infection – the so-called asthenic trace.

“This is a signal that the body has coped with the infection, but is still weak and there is a risk of getting sick again,” the expert explained.

In addition, exposure to heat and cold, physical activity, consumption of spicy foods and/or heavy meals, and pregnancy (up to 37.4 degrees are common) can cause slight changes in temperature.

“37.1–38 degrees is the so-called subfebrile temperature. It may persist for up to two weeks after infection with fever. In the absence of other symptoms, this condition does not require additional examination and treatment. Quite often, colds occur in an erased form, and the detection of temperature is an accidental finding, ”added Tolstykh.

Speaking of elevated temperature, she emphasized that such a reaction of the body is its response to the introduction of a pathogenic microorganism. With good tolerance, fever up to 38.6 is better not to bring down the intake of antipyretics, since bacteria and viruses reproduce worse at elevated ambient temperatures, the doctor recommended, specifying that this concerns a healthy young body without concomitant pathology.

However, there are exceptions to this general rule. Body temperature should be treated more carefully in some cases.

“Firstly, in the pathology of the cardiovascular system (in particular, coronary heart disease, heart failure), an increase in temperature causes a high load on the heart, an increase in heart rate, therefore, in such cases, the temperature drop threshold can be reduced to 38 degrees. Secondly, with a non-infectious cause of fever (paraneoplastic, that is, tumor diseases, fever, fever in rheumatoid diseases), it makes no sense to withstand high temperatures, ”the specialist said.

According to Tolstoy, children usually tolerate temperatures up to 39 degrees, but the doctor noted that there are people who are sensitive to febrile convulsions, that is, their development when the body temperature rises.

Usually we are talking about a fever above 40 degrees, but convulsions individually can develop at a temperature of 39 degrees or even lower. In such cases, it is important to remember this feature of the child and prevent such an increase in temperature.

“At a temperature of 41 degrees and above, the protein begins to denature everywhere, in fact, the body is boiling – such a temperature is life-threatening,” the expert draws attention. In this case, the temperature must be lowered – antipyretics, cooling with a cold blanket and rubbing will help.

The temperature has risen. What you need to know

37.0 — is this already a disease? When should you take an antipyretic? Can heat kill? Why is it advised to eat less at a temperature? We analyze popular questions

Usually we consider a fever a sign of SARS, influenza or other infectious disease. However, it can also jump after vaccination, although there is no infection in the body. Deviations from the temperature norm have dozens of reasons. To understand why this happens, it is worth learning more about the thermoregulation of our body.

In 1851, the German physician and scientist Karl Wunderlich summarized the results of a million temperature measurements in the armpits of patients and for the first time established the normal limit of 37°C, or 98.6°F. He also put into practice regular measurements of the temperature of patients and argued that fever (fever) is not the disease itself, but its symptom.

However, later studies revised Wunderlich’s estimate and reduced the rate to 36.6°C. This was due not so much to the scientist’s mistakes as to the improvement in the quality of life. Wunderlich lived in an era when the average life expectancy was 38 years, and many people suffered from chronic infections such as tuberculosis, syphilis and periodontitis. A high level of systemic inflammation in the body could lead to such a norm.

At the same time, the temperature norm also depends on the place of measurement: in the armpit – it is 36. 6 ° C, in the anus and vagina – 37.5 ° C; in the mouth – 37.0 ° C. By the way, the axillary method is considered the least accurate, but it has entered hospital practice as the simplest and most hygienic. For example, in the United States at home, a thermometer is placed in the mouth. But not any thermometer is suitable for this, you need a special one.

No. The temperature depends on daily biological cycles (at night and in the morning it is lower than during the day and in the evening), physical and mental activity, emotional state (fear, stress), and ambient temperature. Also, temperature regulation is disturbed by drug and alcohol intoxication. A constant temperature of 37.2 ° C can be in women during the period of ovulation and in pregnant women. Therefore, it is important to measure the temperature, if possible, in a calm, unexcited state.

Without illness or other physiological disturbances, the temperature will not exceed 37.2°C. But then begins what experts call subfebrile (from the Latin febris – fever) temperature – from 37. 2 to 37.8 or even 38.0 ° C. Usually she speaks of a sluggish inflammatory process, that the body is fighting infections, and other disorders.

Subfebrile temperature can be distinguished by other signs of the disease – weakness, headache, sweating and body aches.

Yes, but not only. Subfebrile temperature can be observed in hundreds of different conditions. These can be various kinds of infections (for example, this is one of the symptoms of early tuberculosis), poisoning, dental diseases, allergic reactions, latent autoimmune diseases and chronic pathologies.

The temperature within these limits can also increase after receiving a dose of ionizing radiation of 2 to 4 Gy, against the background of hormonal changes in women during menopause. With prolonged or very acute stress, the body can also respond with an increase in temperature – this condition is called psychogenic fever, or thermoneurosis.

It is worth noting that such a temperature in itself does not harm the body. It is simply a tool the body uses to deal with real or imagined threats. For example, an increase in temperature after vaccination is considered a variant of the norm: the body thinks that it is being attacked, and just in case, it “alarms” all defenses.

Infectious agents such as viruses, bacteria and fungi do not live comfortably at certain temperatures. Let’s say 37.0 is already above the average annual temperature of any place on Earth, including the Sahara and the South American tropics. And the higher the column crawls, the worse it is for microorganisms. For example, biologist Arturo Casadevall studied the temperature preferences of 4,082 species of lower fungi. It turned out that less than a third survive at temperatures above 37°C, and only five percent grow at 41°C.

An increase in temperature is an element of non-specific (aimed at a wide range of threats) immunity. The hypothalamus, located at the base of the brain, is responsible for temperature regulation. It responds to signals from biochemical substances floating in the blood, called pyrogens (from other Greek πῦρ – “fire”). At elevated temperatures, metabolic processes are faster, and therefore the action of immune cells is accelerated.

Pyrogens are secreted mainly by cells of the immune system (monocytes, macrophages, T- and B-lymphocytes). When the hypothalamus detects them, it tells the body to generate and retain more heat, causing a fever. In children, the temperature usually rises faster because their immune system is still immature.

It should be said right away that mercury thermometers in Russia have been banned for production since 2020. This is due to the fact that in 2014 Russia signed the Minamata Convention on Mercury, which requires the production, export and import of goods containing mercury and mercury compounds to be stopped.

The advantages of mercury thermometers are their high accuracy (0.1°C error) and reliability. Mercury expands itself due to heat, does not require batteries and microcircuits. But these benefits are outweighed by the health risks posed by mercury vapor from a broken appliance.

Electronic thermometers are more “capricious”, although formally their accuracy is the same. They use a thermal sensor, so they need to be pressed closer to the body – and it is best to measure them orally or rectally. If you do not change the battery in time, the device will begin to “lie”.

But infrared thermometers have lower accuracy. This is due to the fact that the measuring beam passes through the air, which has its own temperature, and this distorts the result (up to 0.2°C). But it gives the result in a matter of seconds, and is convenient when you need to identify a febrile temperature.

A medical thermometer usually ends at 45°C. At 42°C, irreversible decomposition of proteins in the body begins, at 43°C, denaturation (thermal decay) of proteins in brain neurons, which leads to inhibition of brain functions, coma and death.

But even a temperature above 38°C (it is called febrile) is already quite difficult for the body. Blood pressure rises, heart rate rises, the number of decay products of bacteria in the blood increases, which can cause symptoms of poisoning and disrupt brain function (hence hallucinations).

Consequences of prolonged fever may include fainting, heart and kidney failure, dehydration, digestive and nervous system disorders.

As we found out, the temperature helps to fight the disease. Therefore, doctors usually advise taking antipyretics only when the temperature exceeds 38-38.5 ° C. But it depends on the state of the person himself, on how he tolerates the fever. In this case, an overdose of the drug can cause serious damage to the liver, kidneys, gastrointestinal tract, heart and brain.

If the fever is due to hormonal causes, such as hot flashes during menopause or a thyroid disorder (hyperthyroidism), these medicines will not work. In such cases, cooling treatments such as rubbing with a damp towel or bathing in cool water help.

As far back as the 1574 dictionary of John Whizels, it was noted that “fasting is an excellent remedy for fever. ” But if the recommendation to drink more fluids has an obvious explanation (replenish fluid balance and remove the breakdown products of pathogens from the body), then what about the advice to eat less?

On the one hand, in order to maintain a high temperature, the body needs additional energy, which it can get from food. Fasting also creates additional stress. On the other hand, overeating and eating too spicy, unusual, unfamiliar foods can be harmful. The body may misinterpret certain substances as allergens and provoke a reaction.

Such a method exists. For example, in the middle of the 20th century, the German physician von Ardenne began to use it on cancer patients as a means of “last hope”. The fact is that cancer cells die at temperatures close to 42°C. Von Ardenne was able to heat patients up to 41.8°C. True, no more than 17% of them survived, but they were cured.

The “water” method was used for heating. The patient was placed in a special bath and with the help of water-jet devices placed over the patient, and poured over with heated water.