Everyday Health

5 Reasons Why You Might Have the Chills

Originally published September 13, 2019

Last updated April 23, 2024

Reading Time: 4 minutes

A woman with the chills crosses her arms over her chest

Are chills serious? Shivering and goose bumps can accompany a wide range of conditions, from a too-cold environment to cancer.

Maintaining our core temperature is one of the body’s most basic functions, and when that temperature is off — or when our body thinks it’s off — we get the chills.

“Chills occur when the muscles contract and relax in order to make heat,” says Rose Taroyan, MD, a family medicine physician at Keck Medicine of USC and clinical assistant professor of family medicine at the Keck School of Medicine of USC. “This occurs when you are cold, but it can also be your body’s defense mechanism in fighting an infection.”

Everyone knows the sensation of getting the chills when your environment is too cold. That’s usually a signal to put on more layers or turn up the heat. But there are many underlying medical conditions that can cause them, too. Read on for some common — and not so common — causes of chills.

1. You have a viral or bacterial infection.

When chills are accompanied by other symptoms, such as fever, body aches or fatigue, they’re more likely associated with a systemic infection, such as flu or pneumonia.

“Chills boost your body’s core temperature when your immune system attempts to fight off infection,” Taroyan explains. “Your body temperature increases, even though you might feel cold. If you have a viral infection, you will usually notice other symptoms along with chills, such as sore throat, cough, headache, fatigue and muscle aches. Most of the time, it can be self-limiting and will resolve within 2 weeks. It’s important to get plenty of rest and increase your fluid intake.”

2. You have low blood sugar.

Although many people feel a bit shaky and irritable when they need to eat, true hypoglycemia, or low blood sugar, most often occurs in people who have diabetes.

“One of the symptoms of hypoglycemia is a feeling of shakiness, which may mimic chills,” Taroyan says. “Hypoglycemia requires immediate treatment to get blood sugar levels back to normal.”

Defined as blood glucose of less than 70 milligrams per deciliter, hypoglycemia can cause a variety of other symptoms, including sweating, confusion, a rapid heartbeat, blurry vision, lightheadedness and drowsiness.

If you have diabetes and you notice these symptoms, follow the “15-15” rule: Have 15 grams of simple carbs, such as a glucose tablet, juice, honey or hard candy, and check your blood glucose again in 15 minutes. Then eat a meal, but don’t overeat, or your blood sugar will spike.

3. You’re having a panic attack.

Chills can occur if you have a profound or intense emotional reaction to a situation, according to Taroyan. “Emotions that might cause chills include fear or anxiety,” she says.

According to the American Psychiatric Association, nearly 30% of all adults will experience an anxiety disorder during their lifetime. A panic attack can cause a combination of physical as well as psychological symptoms, including chills, shortness of breath, heart palpitations, sweating, dizziness and chest pain. Because of the severity of the symptoms, a panic attack sometimes causes people to think they’re having a heart attack.

If you’ve never had a panic attack before, seek medical attention. If you’ve been diagnosed with an anxiety disorder, psychotherapy (“talk” therapy) and medication can help.

4. You have malaria.

Symptoms of malaria, a disease spread by infected mosquitos, can mimic those of a cold or flu. In addition to chills, they can include fever, sweats, head and body aches, nausea and fatigue. A simple blood test can identify the presence of the malaria parasite, but since malaria is relatively rare in the United States, your doctor might not immediately test for it. If you’ve traveled to regions where the disease is common, such as sub-Saharan Africa, Southeast Asia, parts of India and parts of Central and South America within the last 12 months, be sure to mention it when you’re being evaluated, even if you took antimalarial medications.

5. You have leukemia.

Chills can also be a sign of blood cancers, including leukemia. Symptoms of leukemia may include swelling of the lymph nodes, along with fever, chills, fatigue, loss of appetite, night sweats, abdominal pain and recurring infections. If you have a fever and chills that just won’t go away, see your doctor, in case it’s something more serious.

Having the chills may be nothing more than the body’s attempt to warm you up, but if they’re accompanied by other symptoms, that’s the time to seek medical attention. “Please schedule an appointment with your primary care physician for further evaluation,” Taroyan advises.


Tina Donvito
Tina Donvito is a freelance writer covering health, culture, travel and parenting.