What is considered a dangerous body temperature in adults. How high should a fever be before seeking medical attention. When should you worry about a fever in adults. What causes fevers with no other symptoms.

What Constitutes a Fever in Adults?

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, designed to create an environment less hospitable for pathogens. While fevers can be concerning, they’re often a sign that your immune system is working effectively to combat illness.

Interestingly, it’s possible for adults to develop a fever without experiencing any other symptoms. This phenomenon can leave both patients and healthcare providers puzzled. In many cases, viral infections are the culprits behind these isolated fevers.

Common Causes of Fevers Without Other Symptoms

• COVID-19
• Common cold or flu
• Bronchitis
• Gastroenteritis (stomach bug)

These viral infections often resolve on their own within a few days, which is why healthcare professionals frequently use the term “viral” as an explanation for fevers of unknown origin.

When Does a Fever Become Dangerous for Adults?

While most fevers are not immediately dangerous, there are certain thresholds and circumstances that warrant medical attention. A high-grade fever in adults is considered to be 103°F (39.4°C) or higher. However, the decision to seek medical care shouldn’t be based solely on the temperature reading.

Signs You Should Seek Medical Attention for a Fever

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
5. You’re pregnant
6. You’ve recently returned from overseas travel
7. You’re prone to frequent infections
8. You’re undergoing chemotherapy (seek immediate medical attention if the fever lasts more than an hour)
9. You’ve recently been bitten by a tick

The Myth of 98.6°F as “Normal” Body Temperature

For centuries, 98.6°F (37°C) has been considered the average normal body temperature. However, recent research suggests that this long-held belief may no longer be accurate. In fact, normal body temperature can range from about 97°F to 99°F (36.1°C to 37.2°C).

Why Is the “Normal” Temperature Changing?

Scientists have proposed several theories to explain this shift in average body temperature:

• 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 highlights the importance of considering individual baselines and overall health context when evaluating fevers.

Fever Management and Home Care

While fevers can be uncomfortable, they’re often a sign that your body is effectively fighting an infection. In many cases, home care is sufficient for managing a fever. However, it’s crucial to know when to seek medical attention.

Tips for Managing a Fever at Home

• Stay hydrated by drinking plenty of fluids
• Rest and avoid overexertion
• Use over-the-counter fever reducers like acetaminophen or ibuprofen as directed
• Dress in lightweight, breathable clothing
• Keep the room temperature comfortable, but not too cold

Remember, “Don’t fear the fever” is a common saying among healthcare professionals. Fevers are often your body’s first line of defense against infections.

Fever and COVID-19: What You Need to Know

In the context of the ongoing COVID-19 pandemic, fever has taken on new significance as a potential symptom of the virus. While a fever alone doesn’t necessarily indicate COVID-19, it’s important to be aware of the possibilities, especially if you’re not fully vaccinated.

Can Vaccinated Individuals Still Get Fevers from COVID-19?

Yes, although it’s less common. Breakthrough cases of COVID-19 in fully vaccinated individuals have been reported, but symptoms tend to be milder than in unvaccinated people. This includes fevers, which may be less severe or less frequent in vaccinated individuals who contract the virus.

If you develop a high-grade fever and are not fully vaccinated against COVID-19, it’s crucial to contact your healthcare provider promptly for guidance.

The Importance of Accurate Temperature Measurement

When monitoring for a fever, it’s essential to use the correct method for taking your temperature. Inaccurate readings can lead to unnecessary concern or, conversely, a false sense of security.

Best Practices for Temperature Taking

• Use an oral thermometer for the most accurate results in adults
• Wait at least 30 minutes after eating or drinking hot or cold substances before taking your temperature
• Ensure the thermometer is clean and properly calibrated
• Follow the manufacturer’s instructions for your specific thermometer model

By adhering to these guidelines, you can ensure more reliable temperature readings and make more informed decisions about your health.

Fever in Special Populations: When to Be Extra Cautious

While fevers are generally not dangerous for healthy adults, certain groups of people should exercise extra caution when experiencing elevated body temperatures. These individuals may be at higher risk for complications or may have underlying conditions that can be exacerbated by a fever.

High-Risk Groups for Fever Complications

• Elderly individuals (65 years and older)
• People with compromised immune systems
• Individuals with chronic medical conditions
• Pregnant women
• Recent travelers to areas with endemic diseases

If you fall into any of these categories and develop a fever, it’s advisable to consult with a healthcare professional sooner rather than later. Early intervention can prevent potential complications and ensure appropriate treatment.

Understanding the Body’s Temperature Regulation

The human body’s ability to regulate its temperature is a complex and fascinating process. The hypothalamus, a small region at the base of the brain, acts as the body’s thermostat, working to maintain a stable internal temperature.

How Does Fever Affect the Body?

When the body detects an infection or other threat, the hypothalamus can raise the temperature setpoint, leading to a fever. This elevated temperature can have several effects:

• Accelerated metabolism, which can help the body fight infection more effectively
• Increased production of white blood cells and antibodies
• Creation of a less hospitable environment for pathogens
• Enhanced effectiveness of certain medications

Understanding these mechanisms can help put fevers into perspective and alleviate some of the anxiety associated with elevated body temperatures.

The Role of Fever in Different Types of Infections

While fevers are commonly associated with viral infections, they can occur with various types of illnesses. The pattern and duration of a fever can sometimes provide clues about the underlying cause.

Fever Patterns in Different Infections

• Viral infections: Often cause rapid onset fevers that last for a few days
• Bacterial infections: May lead to higher, more persistent fevers
• Parasitic infections: Can cause cyclical fevers that come and go at regular intervals
• Fungal infections: May result in low-grade, chronic fevers

While these patterns can be informative, they’re not definitive. A healthcare professional can provide a more accurate diagnosis based on a comprehensive evaluation.

Fever-Reducing Medications: Benefits and Precautions

Over-the-counter fever-reducing medications, such as acetaminophen (Tylenol) and ibuprofen (Advil, Motrin), can provide relief from the discomfort associated with fevers. However, it’s important to use these medications judiciously and understand their limitations.

Considerations When Using Fever Reducers

• Follow dosage instructions carefully to avoid potential side effects
• Be aware that reducing fever may mask symptoms of underlying conditions
• Understand that these medications treat symptoms but don’t address the root cause of the fever
• Consult a healthcare provider before using fever reducers in children or if you have chronic health conditions

While fever-reducing medications can provide comfort, they should be used in conjunction with other self-care measures and under the guidance of a healthcare professional when necessary.

The Impact of Environmental Factors on Body Temperature

External factors can influence body temperature, potentially leading to misinterpretation of fever symptoms. Understanding these influences can help you more accurately assess your health status.

Environmental Factors Affecting Body Temperature

• Ambient temperature and humidity
• Physical activity level
• Time of day (body temperature naturally fluctuates throughout the day)
• Clothing choices
• Recent food or beverage consumption

When monitoring for a fever, try to account for these factors and take your temperature under consistent conditions for the most reliable results.

Fever and Sleep: Managing Discomfort at Night

Fevers can be particularly troublesome at night, disrupting sleep patterns and causing discomfort. However, there are strategies you can employ to promote rest and recovery during nighttime fevers.

Tips for Managing Nighttime Fevers

• Use lightweight, breathable bedding
• Keep a glass of water nearby to stay hydrated
• Consider using a cool, damp cloth on your forehead or wrists
• Ensure your bedroom is at a comfortable temperature
• Take fever-reducing medication before bed if advised by your healthcare provider

Remember that sleep is crucial for recovery, so creating an environment conducive to rest can support your body’s healing process.

When Fever Persists: Chronic and Recurrent Fevers

While most fevers resolve within a few days, some individuals may experience persistent or recurrent fevers. These situations can be more challenging to diagnose and manage.

Types of Prolonged Fever

• Fever of unknown origin (FUO): A fever lasting more than three weeks with no apparent cause
• Periodic fever syndromes: Rare conditions characterized by recurrent episodes of fever
• Chronic fever: A low-grade fever that persists for an extended period

If you experience prolonged or recurrent fevers, it’s essential to work closely with a healthcare provider to identify the underlying cause and develop an appropriate treatment plan.

Fever in the Workplace: Balancing Health and Responsibilities

In light of recent global health events, fever awareness in the workplace has become increasingly important. Employers and employees alike must navigate the balance between maintaining productivity and protecting public health.

Workplace Considerations for Fever Management

• Implement clear policies for temperature checks and illness reporting
• Encourage employees to stay home when experiencing fever or other symptoms
• Provide resources for remote work when feasible
• Ensure adequate sick leave policies to support employee health
• Maintain open communication channels for health-related concerns

By fostering a culture of health consciousness and providing supportive policies, workplaces can contribute to overall community well-being while maintaining operational efficiency.

The Future of Fever Monitoring: Technological Advancements

As technology continues to advance, new tools and methods for monitoring body temperature are emerging. These innovations have the potential to revolutionize how we detect and manage fevers.

Emerging Technologies in Temperature Monitoring

• Wearable devices with continuous temperature tracking
• Smart thermometers that sync with mobile apps for trend analysis
• Non-contact infrared thermometers for quick and hygienic readings
• Thermal imaging cameras for mass temperature screening
• AI-powered systems for early fever detection and pattern recognition

While these technologies offer exciting possibilities, it’s important to remember that they should complement, not replace, professional medical advice and traditional diagnostic methods.

Fever Myths and Misconceptions: Separating Fact from Fiction

Despite widespread education on fever management, many myths and misconceptions persist. Addressing these inaccuracies can help individuals make more informed decisions about their health.

Common Fever Myths Debunked

• Myth: Fever is always dangerous and must be treated immediately
• Fact: Most fevers are beneficial and don’t require immediate treatment
• Myth: The higher the fever, the more serious the illness
• Fact: The severity of illness doesn’t always correlate with temperature
• Myth: Fevers can cause brain damage
• Fact: Typical fevers (under 106°F/41.1°C) do not cause brain damage
• Myth: Bundling up helps “sweat out” a fever
• Fact: Excessive bundling can actually increase body temperature and discomfort

By dispelling these myths, we can promote more rational and effective approaches to fever management, reducing unnecessary anxiety and inappropriate interventions.

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.