Chills are a common symptom that most Canadians will experience at some point in their lives. They cause a feeling of coldness along with shaking or shivering muscles. In many cases, chills appear suddenly and are linked to a fever or an underlying infection. This article explains what causes chills, how they are diagnosed, and how they are treated — so you know exactly what to do when they strike.

What Are Chills?

Chills happen when your muscles contract and relax very quickly. This rapid movement generates body heat and is your body’s natural response to cold or illness. Your brain plays a central role in this process.

When an infection enters your body, your immune cells release certain chemicals into your bloodstream. These chemicals signal your brain to raise your body temperature. As your temperature climbs, you may feel cold and begin to shiver — these are chills. This is why chills and fever so often appear together.

Common Causes of Chills

There are many reasons why chills develop. Some causes are mild and short-lived. Others may point to a more serious health condition that needs medical attention.

Infections

Infections are the most common trigger for sudden chills. Both viral and bacterial infections can cause this symptom. Common examples include:

  • The common cold

  • Influenza (the flu)

  • Gastroenteritis (stomach flu)

  • Urinary tract infections (UTIs), such as cystitis or kidney infections

  • Pneumonia

  • Strep throat

  • Mononucleosis (mono)

  • Meningitis

  • Septicemia (a serious blood infection)

  • Malaria

  • Tuberculosis (TB)

According to Health Canada, respiratory infections like the flu are among the leading causes of fever and chills in Canadians each year. Getting your annual flu shot is one of the best ways to reduce your risk.

Cold Weather Exposure

You do not always need a fever to experience chills. Simply being too cold can trigger shivering. Older adults and newborns are especially sensitive to low temperatures and may develop chills more easily than others.

Menopause

Menopause can cause a range of symptoms, including hot flashes and chills. Hormonal changes — particularly a drop in estrogen — can disrupt your body’s ability to regulate temperature. As a result, many women experience sudden episodes of feeling cold or overheated.

Medications

Some medications list chills as a side effect. These include certain antibiotics, interferon beta (used for multiple sclerosis), and some anti-seizure drugs. If you recently started a new medication and are experiencing chills, speak with your pharmacist or doctor.

Autoimmune Conditions

Autoimmune diseases occur when your immune system mistakenly attacks healthy tissue in your body. Conditions like lupus and certain types of anaemia can cause chills. These conditions often require long-term management with medication.

Other Causes

Several other health factors can also contribute to chills. These include:

  • Hypothyroidism (an underactive thyroid gland)

  • Diabetes

  • Malnutrition or low levels of vitamin B

  • A weakened immune system (for example, in people living with HIV/AIDS or cancer)

  • Certain cancers, such as leukaemia or lymphoma

  • High levels of stress or poor overall health

Chills Symptoms: What to Watch For

Chills often appear alongside other symptoms depending on the cause. Recognising these patterns can help you understand what your body is trying to tell you.

Chills With Fever

This is the most common combination. A fever above 38°C (100.4°F) along with shaking chills usually points to an infection. You may also notice sweating, headache, muscle aches, and fatigue.

Chills Without Fever

It is possible to have chills without a measurable fever. This can happen with anxiety, low blood sugar, anaemia, or early-stage infections. However, it is still worth speaking to a healthcare provider if chills without fever are unexplained or persistent. For more information, the Mayo Clinic’s overview of chills provides a helpful breakdown of possible causes.

Chills in Children

Children often experience chills when they have a fever from a cold, flu, or ear infection. Keep them warm, make sure they stay hydrated, and monitor their temperature closely. Contact your family doctor if a child under three months has any fever at all.

How Are Chills Diagnosed?

Your doctor will start with a physical exam and ask about your symptoms, medical history, and any recent travel or exposure to illness. In many cases, a thorough exam is all that is needed to identify the cause of your chills.

However, in some cases, your doctor may order additional tests. These can include:

  • A complete blood count (CBC) to check for infection, anaemia, or blood cancers

  • A urine culture to look for a urinary tract infection

  • Blood hormone levels if menopause or thyroid issues are suspected

  • Antibody tests if an autoimmune disease is a possibility

  • A chest X-ray if pneumonia is suspected

Furthermore, your doctor may refer you to a specialist depending on what the initial tests reveal. Your provincial health plan generally covers these diagnostic tests when ordered by a licensed physician.

Treatment for Chills

Treating chills means treating the underlying cause. There is no single cure for chills on their own. However, there are several approaches your doctor may recommend.

Over-the-Counter Medicines

Acetaminophen (such as Tylenol) or ibuprofen (such as Advil) can help bring down a fever and ease discomfort. Always follow the directions on the label. These are widely available at Canadian pharmacies without a prescription.

Keep in mind that ibuprofen may irritate your stomach and cause allergic reactions in some people. It is not recommended for children under six months of age without medical advice.

Antibiotics for Bacterial Infections

If a bacterial infection is causing your chills, your doctor may prescribe antibiotics. It is very important that you do not take antibiotics without a prescription. Using them incorrectly contributes to antibiotic resistance, which is a growing public health concern in Canada.

Hormonal Therapy for Menopause

Women experiencing chills due to menopause may benefit from hormone replacement therapy (HRT). HRT uses estrogen — and sometimes progesterone — to help balance hormone levels. However, HRT does carry risks, including a slightly higher chance of blood clots. Your family doctor or a menopause specialist can help you weigh the benefits and risks.

Managing Autoimmune Conditions and Cancer

Autoimmune conditions may require anti-inflammatory medications or drugs that suppress the immune system. Cancer-related chills may require surgery, chemotherapy, or radiation therapy. These treatments each carry their own side effects, so your care team will discuss the best options for your specific situation.

Medication-Induced Chills

If your chills are a side effect of a medication, your doctor may adjust your dose or switch you to a different drug. Do not stop taking a prescribed medication on your own — always consult your doctor first.

When to See a Doctor

Many cases of chills are mild and resolve on their own within a day or two. However, some situations require prompt medical attention. Visit your family doctor or a walk-in clinic if you experience any of the following:

  • A fever above 39°C (102.2°F) that lasts more than two days

  • Chills that return repeatedly over several days or weeks

  • Chills accompanied by a severe headache, stiff neck, or rash

  • Difficulty breathing or chest pain

  • Signs of dehydration, such as dark urine, dry mouth, or dizziness

  • Chills in a newborn or a very young infant

  • Chills in someone with a weakened immune system, such as a person undergoing chemotherapy

  • Unexplained chills that have no obvious cause

If you are unsure whether your symptoms require urgent care, you can also call 811 (Health811 in Ontario, 8-1-1 in BC, or your province’s equivalent nurse hotline) to speak with a registered nurse at no cost. Most provincial health plans cover these services. The World Health Organization’s guidance on seasonal influenza is also a helpful resource if you suspect the flu is causing your chills.

Long-Term Outlook

Chills themselves are temporary and do not cause lasting harm. However, the underlying condition responsible for your chills will determine your long-term health outlook.

For example, a common cold typically clears up within a week with no lasting effects. Pneumonia can be treated successfully in most people, though severe cases can be life-threatening. Autoimmune diseases may cause ongoing damage to organs like the kidneys, joints, or lungs if not managed properly.

People dealing with chronic conditions — such as cancer, lupus, or diabetes — should follow up regularly with their healthcare team. Watching for new or worsening symptoms is an important part of long-term disease management. Any new symptom, including recurring chills, should be reported to your doctor promptly.

Frequently Asked Questions About Chills

What causes chills without a fever?

Chills without a fever can occur due to cold exposure, low blood sugar, anaemia, anxiety, or an early-stage infection before the fever develops. In some cases, an underactive thyroid (hypothyroidism) or poor nutrition can also trigger chills without a measurable temperature rise. If you experience unexplained chills regularly, it is worth speaking to your family doctor to rule out an underlying cause.

How do I stop chills at home?

To ease chills at home, wrap yourself in a warm blanket, drink plenty of fluids, and rest. If you have a fever along with your chills, acetaminophen or ibuprofen — available at any Canadian pharmacy — can help reduce your temperature and discomfort. However, if your chills are severe, persistent, or accompanied by other concerning symptoms, visit a walk-in clinic or your family doctor.

Can stress cause chills?

Yes, stress and anxiety can sometimes trigger chills or shivering, even without an infection or fever. This happens because stress activates your body’s fight-or-flight response, which can affect muscle tension and temperature regulation. If stress-related chills are a regular experience for you, speaking with a healthcare provider is a good first step.

Are chills a sign of COVID-19?

Yes, chills are listed as one of the recognised symptoms of COVID-19, often appearing alongside fever, cough, and fatigue. If you have chills and suspect you may have been exposed to COVID-19, follow current public health guidance from your provincial health authority and consider getting tested. Health Canada continues to update its COVID-19 guidelines as the situation evolves.

When should I go to the hospital for chills?

You should seek emergency care if your chills are accompanied by a very high fever (above 40°C), a stiff neck, severe difficulty breathing, chest pain, confusion, or signs of a serious infection like sepsis. For less urgent concerns, a walk-in clinic or a call to your provincial nurse hotline (such as 811) can help you decide on the right next step. Do not hesitate to seek care if you feel something is seriously wrong.

Can chills be a sign of cancer?

In rare cases, persistent or unexplained chills can be associated with certain cancers, such as leukaemia or lymphoma, particularly when accompanied by night sweats, unexplained weight loss, or swollen lymph nodes. However, chills are far more commonly caused by infections or other benign conditions. If you have ongoing chills with no clear cause, your doctor can order the appropriate blood tests to investigate further.

Key Takeaways

  • Chills are a feeling of coldness combined with muscle shivering, often linked to fever or infection.

  • The most common causes include viral and bacterial infections, cold exposure, menopause, and certain medications.

  • Chills can also signal more serious conditions such as autoimmune diseases, thyroid problems, or rarely, cancer.

  • Treatment focuses on the underlying cause — not the chills themselves.

  • Acetaminophen or ibuprofen can help manage fever and discomfort at home.

  • See your family doctor or walk-in clinic if chills are severe, recurring, or accompanied by other worrying symptoms.

  • Call 811 (or your province’s nurse hotline) if you are unsure whether you need medical care.

  • Always speak with a healthcare professional before starting or stopping any medication.

This article is for informational purposes only and is not a substitute for professional medical advice. Always consult your family doctor or a qualified healthcare provider if you have concerns about your health.