Potential causes include:
- being cold
- having hypothyroidism, which causes more sensitivity to cold
- doing intensive exercises in the cold
- having anemia
This article looks at these causes, what a person can do to resolve them, and when they should see a doctor.
1. It is cold
A person may have chills with no fever due to wearing wet clothes and being outside in windy conditions.
The most common reason for a person to have chills with no fever is because of cold weather.
If a person is not wearing sufficient layers and the air temperature is low, they may experience chills.
If a person is wearing wet clothes, they will feel cold more quickly. This is because the water in their clothes evaporates, using the heat energy in their body for this process.
Windy conditions can also make a person feel cold. When the wind blows cold air, it removes warm air trapped around a person's skin or under clothes.
According to the Centers for Disease Control and Prevention (CDC), if a person's body temperature falls too low, they can develop hypothermia. Hypothermia is a potentially life-threatening condition that can make a person confused, tired, and clumsy.
If a person stays too cold for too long, they can fall unconscious, and may eventually die.
By wearing plenty of layers, a person can insulate themselves from the cold and put a barrier between their body and the wind.
Replacing wet clothes with dry clothes is also useful.
Hypothyroidism is when a person's thyroid gland does not produce enough of the hormone that regulates their metabolism.
For some people, this can mean they are more sensitive to the cold and may feel chills more frequently.
According to the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), other symptoms can include:
- gaining weight
- a puffy face
- muscle and joint pain
- dry skin
- thinning hair
- not sweating as much as usual
- irregular or heavy menstrual periods
- fertility issues
- slow heart rate
- an enlarged thyroid
A person should speak to a doctor if they have these symptoms.
Diagnosis and treatment
According to the NIDDK, a doctor can do blood tests to see if a person has an underactive thyroid. If so a person can take medication to replace the hormone that their body is not producing.
3. Infections or malaria
A person will often experience chills and a fever at the same time. However, sometimes the experience of chills can occur before a person gets a fever.
This is possible in response to any infection, but it is a classic symptom of malaria.
Symptoms of malaria
According to the CDC, malaria can have three stages:
- a cold stage, where a person experiences chills
- a hot stage, where they have a high temperature
- a sweating stage
If a person suspects they have malaria, for example, because they live in or recently visited a country where infection can occur, then they should speak to a doctor immediately.
Treatment for infections
According to the CDC, a person's body can usually resolve most common infections, such as flu, by itself. However, if a person's symptoms do not get better, become significantly worse, or they are at high risk of flu-related complications, they should speak to a medical professional.
4. Intensive exercise in the cold
If a person does intensive exercise in cold weather, they might feel chills when they finish the activity. This is in part because a person's body produces heat when they are exercising.
How exercise affects body temperature
When a person stops exercising they will quickly get cold, particularly if they are not wearing sufficient layers to keep them warm after stopping.
Doing intensive exercise may also disrupt a person's ability to regulate their body temperature. This means they may feel chills more than they otherwise might.
To avoid chills after intensive exercise, a person should quickly replace any wet clothing with dry clothing and put on extra layers until they feel warm.
Spinach is rich in iron and can help ward off anemia.
Anemia is when a person does not have enough iron in their blood.
The most common symptoms include waking up tired, looking pale, and always feeling cold with chills.
A person may develop anemia due to poor diet, age, chronic illness, or medication. Women are more at risk than men.
To find out if someone has anemia, a doctor will carry out a blood test.
If someone has anemia, their doctor may recommend taking iron supplements or, in severe cases, a blood transfusion.
Eating a diet rich in iron could help ward off anemia. A diet rich in iron could include:
- spinach — squeeze on some citrus, such as lemon, to help release the iron
- red meat
- peanut butter
- pumpkin or squash seeds
- kidney beans and lentils
- dried fruits
When to see a doctor
If a person experiences chills because they are in a cold climate or are experiencing the early signs of a mild fever, they probably will not need to see a doctor.
However, if a person experiences other symptoms, or they frequently feel cold even when it is warm, and they are wearing many layers, they may have an underlying health issue. A doctor can help diagnose what this is and suggest appropriate treatment.
There is a variety of reasons why a person may experience chills without a fever.
Identifying what is causing the chills will enable a person to either take steps to resolve their chills themselves, or decide if they need to speak to a doctor to get treatment.