Shivering: An Evidence-Based Guide for Patients

Shivering is an involuntary muscle activity that helps the body generate heat, but it can also happen with fever, emotional stress, low blood sugar, medication effects, or medical conditions. Most episodes are temporary, yet persistent, severe, or unexplained shivering should be assessed by a qualified doctor.

What shivering means

Shivering is a rapid, involuntary tightening and relaxing of muscles. It usually happens when the body is trying to raise its temperature, most commonly after exposure to cold. In many cases, shivering is short-lived and settles once the person is warm again.

However, shivering is not always caused by cold weather. It can also occur during a fever, after emotional stress, with certain medicines, or as part of a medical problem that affects metabolism, nerves, or infection risk. The important question is not only whether a person is shivering, but also what else is happening at the same time.

For patients, it can help to think of shivering as a symptom rather than a disease. On its own, it may be harmless. When it appears with other warning signs, persists without a clear reason, or keeps returning, it may signal that the body needs medical attention.

Common signs and associated symptoms

Shivering often feels like trembling or shaking that cannot be controlled. It may affect the whole body or mainly the arms, legs, jaw, or back. Some people also notice goosebumps, chattering teeth, cold hands and feet, or a strong urge to wrap up or move to a warmer place.

When shivering is related to fever, it may be accompanied by chills, sweating, headache, body aches, tiredness, or feeling alternately hot and cold. In infections, symptoms such as cough, sore throat, burning during urination, vomiting, diarrhea, or a new rash may also appear. In these situations, the body is adjusting its internal temperature while responding to illness.

Other symptoms can point toward a different cause. For example, shakiness from low blood sugar may happen with hunger, weakness, dizziness, sweating, or confusion. Anxiety-related shivering may occur with a racing heart, fast breathing, or a sense of panic. Tremor from neurological causes may look similar but is not always the same as true shivering; doctors sometimes consider related movement symptoms and conditions such as Parkinson's disease when shaking is persistent or unexplained.

Causes and risk factors

The most common cause of shivering is exposure to cold. The body’s heat-regulating center in the brain triggers muscle activity to generate warmth. Wet clothing, cold environments, wind exposure, poor heating, and prolonged time outdoors can all make shivering more likely. Babies, older adults, and people who are underweight may become cold more easily.

Fever is another major cause. During infection, the body may raise its temperature set point, creating chills and shivering while it works to reach that new level. Viral illnesses, bacterial infections, pneumonia, urinary infections, and other inflammatory conditions can all lead to this response. In some cases, severe infection can cause intense shaking chills and requires prompt medical assessment.

There are also non-infectious causes. These include emotional stress, panic, low blood sugar, dehydration, thyroid disorders, withdrawal from alcohol or certain drugs, medication side effects, reactions after anesthesia, and some neurological conditions. In a person who also has muscle stiffness, balance changes, or ongoing abnormal movements, a clinician may consider a broader neurological evaluation, including disorders such as essential tremor if appropriate.

• Cold exposure or hypothermia
• Fever from viral or bacterial infection
• Low blood sugar, especially in diabetes
• Anxiety, panic, or strong emotional upset
• Medication effects or substance withdrawal
• Hormonal or metabolic disorders, such as thyroid problems

How doctors diagnose the cause

Diagnosis begins with a careful history and physical examination. A doctor will usually ask when the shivering started, how long it lasts, whether the person felt cold or had a fever, and whether there are other symptoms such as cough, pain, confusion, weakness, or recent illness exposure. Travel history, current medicines, alcohol use, and chronic conditions can also provide important clues.

Checking temperature, heart rate, blood pressure, breathing, and oxygen level helps identify whether shivering is part of a simple reaction or a more serious illness. The doctor may look for signs of dehydration, infection, low blood sugar, thyroid disease, or neurological changes. In children and older adults, the assessment often focuses on hydration, infection signs, and changes in alertness.

Tests are not always needed, but they may be recommended depending on the situation. These can include blood tests, blood glucose measurement, urine testing, and in some cases imaging such as a chest X-ray if a lung infection is suspected. When neurological symptoms are present, further evaluation may be arranged, sometimes with neurology assessment or MRI if the clinical picture suggests a problem involving the brain or nerves.

Treatment options for shivering

Treatment depends on the cause. If shivering is due to being cold, the first steps are gentle warming, dry clothing, warm blankets, and moving to a heated environment. Warm drinks may help if the person is alert and able to swallow safely. In mild cases, this is often enough.

When fever is the cause, management usually focuses on the underlying illness as well as comfort measures such as rest and fluids. A doctor may recommend fever-reducing medicines when appropriate, but it is important not to overbundle someone who already has a high temperature. If there is concern for a significant infection, treatment may include targeted medicines and monitoring.

For shivering linked to low blood sugar, taking a fast-acting source of carbohydrate may help if the person is awake and able to eat or drink, followed by checking glucose and seeking medical guidance. If medication effects, thyroid disease, or a neurological condition are suspected, treatment is directed at that specific issue. Patients with persistent shaking, movement symptoms, or uncertainty about the cause may benefit from movement disorders evaluation to clarify whether the problem is shivering, tremor, or another abnormal movement.

Self-care and prevention

Many episodes of shivering can be prevented with simple practical steps. Dressing in layers, keeping clothing dry, and avoiding prolonged exposure to cold are especially important in winter, during travel, and after water activities. Homes used by older adults and young children should be kept at a comfortable temperature whenever possible.

Good general health habits also reduce the risk of shivering related to illness. Staying hydrated, eating regular meals, managing long-term conditions such as diabetes, and keeping up with recommended vaccinations may lower the chance of fever and metabolic causes. People who know they become shaky when stressed may benefit from slow breathing, rest, and discussing anxiety symptoms with a clinician.

Self-care has limits. It is not advisable to ignore repeated shivering, especially if it is unexplained, severe, or associated with worsening symptoms. If a person seems unusually sleepy, confused, very weak, or unable to keep fluids down, medical assessment is safer than trying to manage the problem at home.

When to seek medical care

Medical advice should be sought if shivering is severe, lasts longer than expected, keeps returning, or happens without an obvious reason such as cold exposure. It also deserves attention when it is accompanied by fever that does not improve, signs of dehydration, persistent vomiting, or symptoms that suggest an infection.

Urgent evaluation is important if shivering occurs with chest pain, shortness of breath, blue lips, confusion, fainting, seizures, a stiff neck, or severe weakness. These symptoms may point to a serious infection, low oxygen level, significant metabolic problem, or another urgent medical condition. Infants, frail older adults, pregnant people, and those with weakened immune systems should be assessed sooner rather than later.

If shivering is part of repeated shaking episodes, new movement problems, or unexplained neurological symptoms, specialist review may be needed. Near the end of the care pathway, patients may wish to know that Acibadem International’s multidisciplinary specialists and JCI-accredited hospitals evaluate and treat underlying causes of symptoms such as shivering for international patients.

Frequently asked questions

Is shivering always a sign of fever?

No. Shivering often happens with fever, but it can also occur when a person is cold, anxious, low in blood sugar, dehydrated, or reacting to medication. The presence of other symptoms helps determine the cause.

What is the difference between shivering and tremor?

Shivering is usually the body's temporary response to cold or fever and involves involuntary muscle activity to produce heat. Tremor is a broader medical term for rhythmic shaking that may be related to neurological, medication-related, or metabolic causes. If shaking is persistent or not linked to feeling cold or ill, a doctor should evaluate it.

Can anxiety cause shivering?

Yes. Anxiety and panic can trigger shaking or shivering because the body's stress response increases muscle tension and adrenaline release. If these episodes are frequent, distressing, or difficult to distinguish from other causes, medical advice is helpful.

Should a person with shivering be covered with thick blankets?

If the person is cold, gentle warming with dry clothes and blankets is appropriate. If shivering is due to fever, heavy covering may make the person more uncomfortable or contribute to overheating. A balanced approach focused on comfort is usually best.

When is shivering an emergency?

Shivering needs urgent medical attention when it occurs with confusion, breathing difficulty, chest pain, fainting, seizures, severe weakness, or signs of serious infection. Emergency care is also important if a person may have hypothermia or cannot stay awake or drink fluids safely.

Can children and older adults be affected differently by shivering?

Yes. Babies, young children, and older adults may become cold more easily and may not describe their symptoms clearly. They can also become dehydrated or seriously ill more quickly, so persistent shivering in these groups should be assessed promptly.

References

• Mayo Clinic
• MedlinePlus
• National Institute of Neurological Disorders and Stroke
• Centers for Disease Control and Prevention
• National Health Service

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.