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Why are you cold when you have a fever: Why Do We Get Chills With Fever?

Why Do We Get Chills With Fever?

That bizarre sensation of shivering while you’re burning up with fever is actually your body’s way of helping you recover faster.

By Kristen StewartMedically Reviewed by Justin Laube, MD


Medically Reviewed

Paying close attention to your other symptoms can help you figure out the cause of your fever and the right treatment.Shutterstock; iStock

We’ve all been there: burning with fever — and shivering with chills at the same time. It turns out that what feels like an odd internal thermostat malfunction is actually a sign that your body is fighting off an infection.

The first thing to understand is that most viruses and bacteria have a hard time surviving above normal human body temperature, which can vary by age, activity, and time of day, but is generally accepted as 98.6 degrees F, according to the U.S. National Library of Medicine.

In fact, even just a one- or two-degree hike in temperature can stop many invading microorganisms in their tracks. So it’s no wonder that over millions of years, fever evolved as a means of helping the body defend itself. “Part of our immune system’s response against infection includes raising the body’s temperature to diminish the ability of microbes to reproduce,” explains Amesh Adalja, MD, a senior scholar at the Johns Hopkins Center for Health Security in Baltimore.

What Makes You Feel Colder When Your Body Is Hotter?

It’s actually a normal physiological response. As soon as your brain shifts its internal thermostat to a higher set point to fight off an infection, the rest of your body goes to work trying to generate extra heat to meet that higher temperature goal. Suddenly, you’re technically below your new “ideal” core temperature, so you feel cold.

Feeling chilled then prompts you to start shivering and even shaking “as your body tries to generate heat to raise your temperature by making your muscles contract,” explains Nate Favini, MD, medical director of the nationwide healthcare system Forward.

How Long Do Fever and Chills Last in Adults?

The length of a fever — and any accompanying chills — can vary significantly depending on its cause. “In some cases with a mild viral illness, a fever can last for a day, or it can last for weeks to months with systemic infections,” says Dr. Adalja.

The best thing to do is play detective to determine the source of your fever based on other signs and symptoms of your illness, he says. Possible causes abound, including colds and the flu, bronchitis, pneumonia, appendicitis, gastroenteritis, mononucleosis, ear infections, sinus infections, and urinary tract infections (UTIs).

While fevers are usually caused by viruses, other conditions that can spike your temperature include certain inflammatory disorders such as lupus, rheumatoid arthritis, and Crohn’s disease, as well as cancer and blood clots (deep vein thrombosis). Even certain medication such as penicillin, sulfa drugs, and antipsychotics can trigger a fever, as can some illegal drugs such as cocaine, according to the Merck Manual.

What Should You Do When You Have the Chills and Fever?

Fevers in adults and the chills that go hand in hand generally resolve within a few days, note Mayo Clinic experts. If your temperature is mildly elevated — between 100 degrees F and 102 degrees F — and you have no other worrisome symptoms (see below), simply rest and drink plenty of fluids to keep from becoming dehydrated.

However, even though you feel cold on the outside, you should keep clothing and blankets light to prevent overheating because inside your body is very hot, say experts at UPMC/University of Pittsburgh Schools of the Health Sciences.

When Should I Call the Doctor?

If your temperature hits 103 degrees F, Mayo Clinic experts advise you to contact your doctor. Per the Merck Manual, you should also consult him or her if:

  • You have a serious medical condition that could make a moderate fever more dangerous, such as a heart or lung disorder
  • A fever lasts more than 24–48 hours

Seek medical help immediately if anything unusual or alarming accompanies the fever and chills, such as any of these symptoms:

  • A change in mental function, such as confusion
  • A headache, stiff neck, or both
  • Flat, small, purplish red spots on the skin, which indicate bleeding under the skin
  • Low blood pressure
  • Rapid heart rate or rapid breathing
  • Shortness of breath
  • Recent travel to an area where a serious infectious disease such as malaria is common
  • Recent use of drugs that suppress the immune system (immunosuppressants)

What Medication, if Any, Should I Take?

Because fever helps the body defend against infection and because a moderate fever itself is not dangerous, Mayo Clinic pros say it’s often best for otherwise healthy adults to let one run its course.

If you’re uncomfortable, however, consider taking an over-the-counter fever reducer, such as Tylenol (acetaminophen), a nonsteroidal anti-inflammatory drug (NSAID) such as aspirin, ibuprofen (Advil, Motrin), or Aleve (naproxen). Follow instructions on the label precisely for proper dosage.

Also be careful not to take more than one medication containing acetaminophen, which is a common ingredient in many over-the-counter medications, including cough and cold remedies. Acetaminophen can cause serious harm to the liver if you take too much.

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Fever and Chills When Sick: What Are Chills?

What are the chills?

If you’ve ever had a high temperature, there’s a good chance you’ve also experienced that strange phenomenon of suddenly feeling very cold or shivery, even though your body is hot1. That feeling is known as ‘the chills’ and they are most commonly associated with fever (a temperature of above 103°F in adults), since chills often happen when the body is about to experience a rise in temperature1,2 and the shivering feeling caused by the chills is simply the result of rapid muscle contractions. These contractions are your body’s way of warming itself up when it’s feeling cold.1

Chills are more common in children than adults, since children are more likely to develop a higher fever than the average grown-up.1

What causes fever with chills?

Since chills are so directly linked with fever, they will most likely share the same cause. A low grade (slight) or high grade fever is your body’s natural response to a viral or bacterial infection. Your body tries to fight off the infection by stimulating your immune system, raising your temperature to help prevent any viruses or bacteria from thriving.3

Some common illnesses that may cause fever and chills include: 4

  • colds or the flu,
  • kidney or urinary tract infections (UTIs),
  • bronchitis,
  • strep throat,
  • ear infections.

If you’re suffering with the flu, you may experience common symptoms such as fever, chills (often sudden fever and chills, since flu symptoms tend to come on very quickly), headaches, body aches and fatigue – as well as other respiratory symptoms.7

Learn more about what colds and the flu look like.

What causes chills but no fever?

There are a few reasons you might experience chills but not fever. Firstly, as mentioned above, chills can often predict a fever or an oncoming rise in the body’s temperature, so it’s possible that you will experience chills and no fever at first, before the fever actually comes on.1

Other potential causes of chills that are not related to fever or infection may include:

  • Being too cold. Yes, it can be that simple. Since chills are the body’s way of trying to increase your temperature, shivering may merely be the result of a freezing winter’s night or being in a room that’s too cold. Your body could just be turning on its natural heating system.1
  • Low blood sugar (hypoglycemia). This is most common in people who have diabetes. If blood sugar levels become too low it can cause shakiness, which often looks similar to the chills.5
  • Panic attacks. Feelings of extreme anxiety can cause serious physical, as well as psychological, distress. Symptoms of a panic attack may include chills, sweats, chest pain, dizziness, heart palpitations and shortness of breath.5
  • Night sweats and chills. Your body is constantly regulating its own temperature, even while you sleep. Most of us know the unpleasant feeling of waking up in the night either freezing cold or feeling so hot it’s as if the room is on fire; moving between chills and sweats. These are ‘night sweats’, and they may occur if your bedroom gets too hot at night, as your body tries to cool you down. The same goes when your bedroom is too cold; you may get the chills as your body shakes to try to get warm again. 6
  • Stomach flu (gastroenteritis). If you’re suffering from stomach pain and chills, there’s a good chance you have a stomach flu. Despite the name, gastroenteritis isn’t caused by the same virus as the regular flu, but by other types of viruses, bacteria or toxins. It can cause terrible stomach pain, diarrhea, nausea or vomiting, headaches and body aches – and of course, fever and chills.8

Treatment – relieving fever

Suffering through fever and its associated chills can be extremely unpleasant, and you may be wondering how to break a fever – or at least reduce it. Thankfully, most fevers will go away naturally within a few days, but there are some simple steps you can take in the meantime to help feel better:3, 9

  • Try a fever-reducing medicine. An over-the-counter medicine like paracetamol or ibuprofen can help to reduce fever. Theraflu Multi-Symptom Severe Cold Hot Liquid Powder will help to both reduce fever and get to work on your worst cold and flu symptoms – including cough, headache, body aches, sore throat pain and congestion.
  • Drink plenty of fluids. This will help to cool your body down and prevent dehydration.
  • Get plenty of rest. Allow your body some time to recover and stay home from work or school.
  • Take a lukewarm bath. Do not try to make yourself colder with a cool or cold bath. You can also apply damp washcloths with slightly warm water to your forehead for some relief.
  • Dress lightly. Wear loose and comfortable clothing, even if you have chills.

It’s important to note that these treatment options are only recommended for fever in older children and adults. Seek immediate medical attention if your child is under 3 months old and has a fever of above 100.4°F, or if they are 3-6 months old and have a fever of above 102°F.10

  • References

    1. Chills. Medline Plus. https://medlineplus.gov/ency/article/003091.htm. Accessed 30/06/20.

    2. Fever (Symptoms & causes). Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/fever/symptoms-causes/syc-20352759. Accessed 30/06/20.

    3. Fever in adults. NHS Inform. https://www.nhsinform.scot/illnesses-and-conditions/infections-and-poisoning/fever-in-adults. Accessed 30/06/20.

    4. Fever: possible causes. Cleveland Clinic. https://my.clevelandclinic.org/health/symptoms/10880-fever/possible-causes. Accessed 30/06/20.

    5. 5 Reasons Why You Might have the Chills. Keck Medicine, University of Southern California. https://www.keckmedicine.org/5-reasons-why-you-might-have-the-chills/. Accessed 01/07/20.

    6. Shivering and sweating at night. National Sleep Foundation. https://www.sleepfoundation.org/bedroom-environment/touch/shivering-and-sweating-night. Accessed 01/07/20.

    7. Flu symptoms. Centers for Disease Control and Prevention. https://www.cdc.gov/flu/symptoms/symptoms.htm.  Accessed 01/07/20.

    8. Gastroenteritis. Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/12418-gastroenteritis. Accessed 01/07/20.

    9. Treating fever in adults. Harvard Health Publishing, Harvard Medical School. https://www.health.harvard.edu/staying-healthy/treating-fever-in-adults. Accessed 01/07/20.

    10. Fever in children. NHS. https://www.nhs.uk/conditions/fever-in-children/. Accessed 01/07/20.

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Why chills happen and what to do about them



November 28, 2018

If you’re shivering, make sure it’s not fatal.

Chills is a physiological reaction of the body to a spasm of superficial blood vessels. Most often, fine shivering is caused by cold. However, chills also have much more unpleasant causes.

Why there is chills at a temperature

After hypothermia, the most common cause of chills is fever. Doctors define this condition as an increase in temperature to 37.7 ° C and above.

Fever itself can be a symptom of a huge number of diseases, including bacterial infections and various inflammatory processes in the internal organs. However, most often we encounter it when we fall ill with ARVI or the flu.

The mechanism of chills in fever is simple. Trying to overcome the infection, the body raises the temperature – this is detrimental to many viruses and bacteria. To speed up the warm-up and keep the heat inside, superficial blood vessels spasm and trembling starts. Therefore, when the temperature rises rapidly, the person looks pale and is desperately shivering.

Why there is chill without fever

1. Cold

It is the cold that causes blood vessels to contract to keep heat inside the body. In response, the body begins to intensively contract and relax the muscles in order to warm up.

You don’t have to jump out into the cold half-dressed to get chilly. A sudden change in temperature is enough (for example, when you go from a hot street into a room with a working air conditioner) or a slight gust of wind when you are wearing wet clothes.

2. Taking medications

Some medications, including over-the-counter medications, cause excessive sweating and chills. These side effects are written in the instructions for use.

Combination or overdose of drugs can also cause shivering.

By the way, for this reason, elderly people often get chills. They take an impressive range of all kinds of drugs, not really reading the instructions.

3. Extreme physical activity

When you run a marathon, swim a kilometer, or do your best in any other way, your muscles generate a lot of heat. Because of this, the body heats up and begins to cool down with the help of sweating.

The temperature difference between the skin and the surrounding air often causes chills. Most often, athletes get chills on too hot (when the body is actively sweating) or too cold days.

4. Endocrine disorders

Constant feeling of cold and associated chills are common symptoms of hypothyroidism (reduced production of thyroid hormones). Due to a lack of hormones, the body cannot effectively regulate temperature. Therefore, it tries to retain heat by spasming the subcutaneous blood vessels and starting to shiver.

5. Menstruation and menopause

Significant hormonal fluctuations also occur in these situations.

6. Hypoglycemia

This is the name given to a sudden drop in blood sugar levels. It may occur for various reasons. For example, you overexerted yourself physically or psychologically. Or sit on a too rigid diet, in which the body does not have enough glucose. Or you suffer from diabetes, but your doctor made a mistake with the dosage of the medicines.

With hypoglycemia, we experience acute weakness, including muscle weakness. Exhausted muscles begin to tremble, chills appear.

Hypoglycemia is a dangerous condition. If the blood sugar level continues to drop, it can lead to damage to the nervous system up to epileptic convulsions, loss of consciousness and coma.

7. Malnutrition

It has the same effect as hypoglycemia. But in this case, muscle weakness is caused by a lack of not only glucose in the blood, but also other nutrients.

If you have regular chills due to diet or weight loss, be sure to see your doctor. After all, after the chills come a breakdown, hair loss, inability to conceive, insomnia, depression and even anorexia, which can be fatal. You need to normalize your diet as soon as possible.

8. Stress and emotional overstrain

Stress increases the level of adrenaline. Among other things, this hormone causes spasm of superficial vessels and, as a result, trembling. That is why people “already shake” when they are angry or very worried.

How to treat chills

Given the variety of causes, there is no general treatment algorithm. It is necessary to act depending on the situation:

  • If you are cold, drink hot tea, try to warm up and relax. This will remove the spasm.
  • If you have chills due to an infection and fever, see your doctor and follow his advice.
  • If you are overextended physically or emotionally, allow yourself a few minutes of relaxation: take a breath, calm down.
  • If you regularly experience chills, see your doctor to rule out hormonal imbalances, developing diabetes, or nutritional deficiencies.

Read also 😨😬😑

  • 6 signs that dizziness is life threatening
  • How to know if you have parasites
  • What will happen to you after giving up sugar

Is the body hot?” — Yandex Q

12.7 K

Alexey Paramonov

gastroenterologist, therapist, PhD, founder and director of the Rassvet Clinic · 1 Jan 2016

When the temperature rises, it is a protective process – fever. Fever is externally manifested by a rise in temperature. But on the part of the body, this is a meaningful action. At a temperature of 39degrees and above, the reproduction of the vast majority of microbes is inhibited. At the same time, the processes in the immune system proceed faster, the body seeks to shorten the period until it can secrete antibodies against the attacked microbe, and until then it destroys it with non-specific means, both molecular, neutralizing the microbe and blocking its spread, and physical – temperature. At the same time, the body turns on a program of fine muscle tremors, which produces a lot of heat and constricts the vessels on the periphery in order to keep this heat inside. Therefore, when the temperature rises, a person is pale and shaking, he is cold, this is called chills. Then the second phase occurs – fever – when a person sweats, the skin turns red, he is hot, the temperature drops.

I note that the sensation of heat or cold will depend not on the temperature numbers, but on its vector: it rises – chills, decreases – fever.

Since fever is a defensive reaction, it does not have to be dealt with directly. Antipyretics should be taken only if you are physically very ill from a high temperature, the numbers do not matter, except in rare cases when they go over 41. But this does not happen with household infections, leave these situations to the doctor.

Masha Gushchina

January 3, 2016

Very interesting answer! Thank you!!

Lesena Sekretovna

dC` 8 Oct 2021

In plain language.
There is a guard in your body, its name is Immunity. He constantly checks his possessions and if he sees an intrusion. Then his soldiers Pyrogens are sent to the Hypothalamus and are like this: “Dude, we have a virus here that cannot exist for a long time at a temperature of 39 degrees, well, move the toggle switch in the center of thermoregulation from the norm towards heat production … Read more

Alsu Almukhametova

March 29

It was very interesting, bravo 👏😄


Mikhail Smolin

neurologist, cephalologist 2 Jan 2016

In the human body, and more specifically in the hypothalamus, there is a group of cells that for body temperature. These cells measure the body’s actual temperature and compare it with the currently set normal temperature.
The “chip” is that the normal temperature is not constant. In case of illness (viral infection, inflammation, etc.), substances are released that this … Read more


Bo Rdo

I plant good, I do justice.
Philosopher, psychologist, aspiring artist and… 29 Mar 2017

In your question, you answered it yourself. The body temperature rises, but the environment does not. That’s why we feel chills. And the higher the temperature, the more chills. Therefore, by the way, doctors do not advise to wrap up, but, on the contrary, to cool the body in every possible way in order to avoid overheating of the body.

Petr Ivanov

March 29, 2017

Thank you! I’m just sick, so it became interesting. And now I don’t sleep, I’m shaking, I ate 2 tablets, I’m waiting for the temperature to subside. )

Oleg Stiranets

May 3, 2018

High temperature and cold, what to do, what pills do you need to help? January 21 2021


Alexander Sterligov

Psychiatrist 29Mar 2017

To fight infections, the body has developed a protective mechanism – fever. With an increase in body temperature, most disease-causing microbes cannot reproduce and function normally.