What Is Fever?

Fever is a natural reaction of your immune system when it detects a threat — usually an infection. The rise in temperature helps your body kill off viruses and bacteria that cannot survive in heat. Although fever may feel uncomfortable, it often means that your immune system is working properly.

Why Fever Matters

Many people underestimate fever and treat it as something insignificant, but it can be one of the earliest signs of serious conditions such as pneumonia, meningitis, or severe viral infections. Recognizing fever early helps avoid delayed treatment and prevents complications that could develop silently.

Common Symptoms

Fever usually comes with chills, sweating, headaches, muscle pain, weakness, and reduced appetite. Some people also experience irritability, dehydration, or trouble concentrating. Children may become unusually sleepy or active.

What Causes Fever?

• Most fevers are caused by:
• viral infections (flu, colds, COVID-19)
• bacterial infections
• throat and ear infections
• sinus infections
• urinary tract infections
• gastrointestinal infections
• inflammatory diseases
• heat exhaustion or dehydration

Complications of Untreated Fever

If not monitored, fever can lead to dehydration, dizziness, fainting, worsening infections, and in severe cases, damage to organs. High fever may also trigger febrile seizures in children — usually harmless but terrifying for parents.

Mistakes People Often Make

• take too many fever-reducing medications
• mix medications unsafely
• continue working despite fever
• avoid eating or drinking
• assume fever is always dangerous
• ignore fever entirely
• bundle up in warm clothes, raising temperature even higher

Myths About Fever

• • Fever always means something serious — false
  • You must bring temperature down immediately — false
  • Fever can “cook the brain” — false unless extremely high
  • Sweating always means recovery — false
  • Only antibiotics treat fever — false, antibiotics treat bacteria, not temperature

How to Treat Fever

The best treatment is rest, hydration, and over-the-counter medications if needed. Avoid alcohol, caffeine, and heavy physical activity.

How to Prepare for a Doctor Visit

Before your appointment, note:

• how long the fever has lasted
• the highest temperature recorded
• all symptoms you feel
• recent travel or contact with sick people
• medications you’ve taken
• any chronic conditions you have

Prevention Tips

Simple habits help reduce the risk of fever-causing infections:

• wash hands regularly
• keep your home clean
• avoid close contact with sick individuals
• boost your immune system with healthy sleep and diet
• stay hydrated every day (p)

FAQ

What temperature is considered a fever?

A fever is generally defined as a body temperature above 100.4°F (38°C). Anything below that is usually considered a normal variation or low-grade elevation.

When should I worry about a fever?

You should seek medical attention if the fever goes above 103°F (39.5°C), lasts more than 3 days, or comes with symptoms like shortness of breath, chest pain, rash, stiff neck, confusion, or severe weakness.

Is fever dangerous by itself?

Mild to moderate fever is usually not dangerous and actually helps your immune system fight infection. However, very high or prolonged fever may lead to dehydration or complications.

Should I always lower a fever?

Not always. If the fever is mild and you feel okay, rest and hydration may be enough. Medication is recommended when the fever causes discomfort, pain, or prevents you from resting.

Can fever be a sign of something serious?

Yes. Fever can indicate pneumonia, meningitis, urinary tract infections, severe viral infections, or inflammatory diseases. That’s why monitoring symptoms is essential.

What is the best medicine for fever?

The most commonly recommended medications in the U.S. are acetaminophen (Tylenol) and ibuprofen (Advil, Motrin). They help lower temperature and reduce pain.

Can dehydration cause fever?

Yes, dehydration can cause a mild fever, especially in hot weather or during intense physical activity.

Is it safe to exercise with a fever?

No. Exercising with a fever puts additional strain on your heart and immune system and may delay recovery. Rest is strongly recommended.

Why does fever cause chills?

Chills occur because your body is trying to raise its internal temperature. Muscles contract rapidly, producing heat and causing the shaking sensation.

Is it normal for fever to rise at night?

Yes. Body temperature naturally fluctuates and often increases in the evening and at night. This can make fever feel worse during nighttime hours.

Can stress cause fever?

Prolonged stress can slightly raise body temperature due to hormonal changes and inflammation, but it usually does not cause high fever.

Does fever always mean infection?

No. Fever can also appear due to inflammation, autoimmune diseases, heat exhaustion, medication reactions, or dehydration.