Here's Why You Feel Like You Have The Chills After A Tough Workout

If you're dealing with the chills but don't have a fever, you may think you're sick or that there's gotta be a fever brewing—especially if you're having symptoms during flu season. So how do you pinpoint what, exactly, is going on?

“Chills are a serious symptom that can present as an early warning sign of underlying infection or illness,” says Keri Peterson, MD, an internal medicine doctor and Women’s Health advisory board member based in New York City. In these cases, a fever builds to fight off whatever infection is impacting the body, and chills are a side effect.

However, chills don’t always mean that you have a fever, and often, there are other underlying health issues at play. “Chills without a fever are arguably more common and can be representative of many things,” notes Neha Vyas, MD, a family medicine physician at Cleveland Clinic. You'll want to pay attention to other symptoms you're having to get to the root cause (more on that soon).

If you have chills but no fever and can't figure out the cause, don't panic. Here are some of the potential reasons you might be feeling the shakes, according to medical experts.

Meet the experts: Keri Peterson, MD, is an internal medicine doctor in New York City and Women's Health advisory board member. Neha Vyas, MD, is a family medicine specialist at Cleveland Clinic.

What does it mean if you have chills but no fever?

First, let's define what chills are and why they happen. Chills reveal that the “body's core temperature is lower than its ideal range, triggering involuntary muscle spasms that aim to conduct heat,” explains Dr. Vyas. Essentially, the body is trying to make itself warm. Chills and shivering are some of the most common symptoms associated with fever, per the Journal of Family Medicine and Primary Care—but what happens when your temperature is stable?

Chills with no fever can reveal underlying conditions ranging from serious to very mundane. It can be as simple as being too cold (which a few warm layers can easily solve!) or the chills might be a symptom of a chronic condition like diabetes or thyroid disease.

10 Potential Reasons For Chills Without Fever

1. Medication Side Effects

“There are tons of medications that may cause side effects of chills, and there are several combinations of drugs that can cause this,” says Dr. Vyas. Some of the most common include insulin and other diabetic drugs, pain medications, and certain migraine meds.

Having high levels of serotonin can also play a role, Dr. Peterson adds. "Serotonin syndrome, a condition where serotonin levels become too high, can be a result of taking a combination of drugs that increase serotonin levels,” she explains. “An example of this would be a selective serotonin reuptake inhibitor (SSRI) and a triptan.”

If you're taking any of these and notice the chills more often, your meds could be the culprit.

2. Hypothyroidism (Underactive Thyroid)

The thyroid is an important organ of the endocrine system that is responsible for releasing hormones that regulate metabolism, development, and growth of the human body, per the NIH. An underactive thyroid “does not produce enough hormones to regulate metabolism [which] can cause sensitivity to cold and chills,” explains Dr. Peterson.

If you're concerned your chills may be a sign of thyroid disease, look out for other symptoms that accompany chills like weight gain, constipation, tiredness, dry skin, muscle weakness, and hair thinning—and always consult a doc to fully assess your symptoms.

3. Hypoglycemia (Low Blood Sugar)

“Patients with immunocompromised conditions such as diabetes may experience chills when their blood sugar is low,” Dr. Vyas explains. As a result of taking too much insulin, blood sugar dips and folks may experience body shakes and jitters as a symptom of hypoglycemia, she adds. Luckily, if caught during early stages, blood sugar can be raised quickly with a sugary drink, glucose tablet, or piece of candy.

Other early warning signs of hypoglycemia include fast heartbeat, shaking, nervousness or anxiety, dizziness, and hunger, according to the Centers for Disease Control and Prevention (CDC). If you're dealing with any of these symptoms, it may be time to make an appointment with your doc.

4. Menopause

Sometimes, hormonal changes can cause chills. “In older women, chills can be a sign of hot flashes or night sweats and are a symptom of menopause,” says Dr. Vyas.

According to the NIH, other symptoms of menopause include trouble sleeping, mood swings, change in period frequency, loss of bladder control, and pain during sex. If you're dealing with any of these along with the chills, speak with your doctor for personalized recommendations to manage your symptoms. They may suggest hormone replacement therapy (HRT), a commonly prescribed treatment to help manage menopause symptoms, but know that there are many options available.

5. Anxiety

“Chills can be a sign of mental health conditions such as anxiety or panic attack disorders,” Dr. Peterson states. According to the American Psychological Association (APA), anxiety is characterized by feelings of tension, worried thoughts, and other physical symptoms like sweating, dizziness, rapid heartbeat, and trembling. If this sounds familiar, talk to your doctor about your treatment options which may include talk therapy and/or medication for anxiety. And in the meantime, practices like breathwork, regular exercise, and cutting back on caffeine can help manage your anxiety symptoms.

6. Stress

While anxiety tends to linger almost all the time (even when there's no stressor), stress is typically more short-term. If you are feeling stressed to the point where you have chills, your body is having a serious reaction, says Dr. Peterson. To help, she recommends looking into relaxation techniques. “With severe stress there is stimulation of the sympathetic nervous system, which releases cortisol, and adrenaline surges into the bloodstream,” she explains. “Adrenaline can cause your body to shake or tremble.” As with anxiety, therapy may be helpful in addition to options such as meditation, breathing techniques, or yoga, Dr. Peterson says.

7. Hangover

Tremors, which can resemble chills, can also be the result of a long night of drinking, as the body is experiencing alcohol withdrawal, says Dr. Peterson. To avoid spending your Sunday in bed recovering from a hangover, try to limit how many drinks you consume, pace yourself, or avoid drinking altogether and invest in new hobbies with people who share a similar mindset, she adds.

8. Excessive Exercise

“Marathon runners or tri-athletes may experience chills after races because it's their body’s way of compensating for that excess energy expenditure,” says Dr. Vyas. After exercising over a long period of time, the body may be dehydrated, overheated, or have low blood sugar, adds Dr. Vyas, requiring you to listen to what your body needs, whether it's food, water, or rest.

9. Cold Temperatures

Sometimes, having chills simply means you're too cold. Perhaps it's chilly outside or the air conditioning in your house is blasting. In this case, get under the covers, pour yourself a cup of hot tea, throw on a few layers, and you should feel warmer soon.

That said, in extreme cases, your body can experience hypothermia, which requires immediate medical attention. Apart from shivering, warning signs of hypothermia include exhaustion, a weak pulse, fast heart rate, and confusion, per the Cleveland Clinic. If you've been in extreme conditions and are concerned about this, seek medical attention ASAP.

10. Cancer

In the most severe cases, chills without fever can be a “systemic response to something going on in your body that's not quite right and could be a manifestation of some sort of internal cancer,” explains Dr. Vyas.

Other symptoms that may signal something serious is going on include sudden weight loss or weight gain, extreme fatigue, fever or night sweats, stomach or back pain, lumps or swelling in the body, or unusual bleeding or bruising, according to the American Cancer Society. Of course, if you have any concerns this could be the case, you should see your doctor ASAP.

Home Remedies For Chills

Until the underlying cause is determined, Dr. Vyas does not recommend any home remedies for chills without fever. If the culprit is as simple as being cold, remedies like heating pads, warm layers, or hot baths can be helpful. However, she notes, chills should be judged in light of other symptoms you may be having. “As a doctor who specializes in chronic diseases and lifetime care, I use the patient’s history to determine if chills reveal there is something very serious or innocuous going on," she says.

When To See A Doctor

If chills become frequent and you cannot find the underlying cause, then it is important to seek medical attention. When working with patients who are experiencing chills, Dr. Peterson explains that she typically conducts a "review of systems" from head to toe, asking about each system in the body to determine what is going on.

You should call a provider if you experience stiffness in the neck, confusion, irritability, sluggishness, or if your chills are accompanied by coughing, shortness of breath, abdominal pain, or frequent urination, according to Mount Sinai. Make note of when your chills began and how frequent they are, and know that your doc will likely check your temperature and potentially run some lab tests to rule out anything serious.

Frequently Asked Questions

Here are some of the most commonly asked questions about chills without fever, and what experts want you to know.

Why do I have chills after exercising?

While exercising, the body’s temperature rises and produces sweat in order to reach its original temperature, explains Dr. Peterson. The skin may feel cold as a result of this process. Excessive exercise may lead to chills as a result of the body compensating for serious energy expenditure, she adds. These symptoms may be alleviated with food, water, and rest.

How do I treat chills with no fever?

“The chills can be a serious symptom that means something is not right in the body,” says Dr. Vyas. Pay attention to accompanying symptoms and treat them according to the underlying cause, she says. If there is no improvement and simple home remedies do not help, seek medical attention.

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