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What is a Fever Dream?

Lara Vargas


People have been captivated by the phenomenon of dreaming for centuries. While it is difficult to unveil the exact reason we dream, sleep experts have found our daily life experiences heavily dictate what we dream about. This is interesting considering most people have at least one dream they remember for its peculiarity.

Perhaps the most peculiar of all, are fever dreams. Fever dreams tend to be extremely detailed, strange, or just plain horrifying. These types of dreams transpire when our internal body temperatures are high. Although high temperatures are our body’s way of fighting off infection, they can have adverse effects like fatigue, chills, body aches, irritability, and fever dreams.

What Defines a Fever Dream?

A healthy body temperature ranges from 97 to 99 degrees Fahrenheit. Anything two degrees above your core body temperature is classified as a fever. Fevers can develop from heat exhaustion, immunization, antibiotics, inflammatory diseases like arthritis, or tumors; but, they are typically the result of a viral or bacterial infection. The body rises to higher temperatures during infection because bacteria and viruses are temperature-sensitive pathogens. A fever basically kick starts the immune system and begins fighting off the illness. Still, fevers come with undesirable side effects like fever dreams.

Fever dreams are especially vivid dreams resulting from high body temperatures. Although most people wish to forget them, their grim nature tends to leave a lasting impression.

In fact, a popular dream study found 94 percent of people who have experienced fever dreams identify them as distressing. The participants of the study described them to be “more bizarre, more emotionally intense, and often negatively toned.” Put simply, fever dreams are confusing and intense nightmares accompanying elevated body temperatures.

What Causes Fever Dreams?

Sleep specialists are not entirely sure why we fever dream, but there are multiple theories related to what we already know about parts of the brain, stages of sleep, and infections.

Some sleep specialists say a fever basically overheats the brain, making it difficult to function properly. There is a small region near the base of the brain called the hypothalamus. The hypothalamus is responsible for maintaining a constant and stable internal environment, also known as homeostasis. One of the hypothalamus’ main duties is to regulate body temperature. However, it can be easily deceived by viral and bacterial pathogens.

Pathogens produce pyrogens, better known as heat-sensing inhibitors. Hindering heat-sensing neurons energizes cold-sensing neurons and tricks the hypothalamus into thinking the body is colder than it actually is. The hypothalamus then heats up the body, causing a fever. Because the hypothalamus is responsible for endorsing sleep as well, fevers also affect our sleep health.

How Do Fevers Affect Sleep Health?

Sleep is composed of two states: Non-rapid eye movement (NREM) and rapid eye movement (REM). Although we spend a majority of the time in the NREM stage of sleep, REM sleep has a greater impact on our psychological state. Along with rapid eye movement, our breathing and heart rate increase to a quick-paced rhythm during the REM state. Most dreams develop during REM sleep, and we usually only remember them if we experience wake time.

Fevers lead to frequent wake time and fragmented sleep. This is because, even if we are healthy, the brain struggles to regulate body temperature during REM sleep. Thus, elevated body temperature will intensify this struggle.

Uncomfortably high body temperatures during sleep can lead to microarousals or constant shifts from REM to NREM. Microarousals may cause us to wake up. In turn, it boosts dream recall frequency–our ability to remember dreams, especially bizarre dreams. Nonetheless, non-fever dreams don’t typically warrant such negative dream emotions or memories.

Why Do Fevers Cause Negative Dream Emotions?

We already know real life significantly impacts the content of dreams. Limited social interaction, extreme heat, distorted figures, and vertigo are all common themes in fever dreams. People who have a fever typically stay home. Perhaps that’s the reason lack of social interaction is regularly reported in fever dreams. High body temperatures also lead to persistent sweating and temporary cognitive impairment, explaining patterns of extreme heat, distorted figures, and vertigo.

What are Fever Dreams Like?

Fever dreams ensue from elevated body temperature. Dreams are almost always a stretch from reality, but fever dreams have proven themselves to be especially bizarre and even frightening. The troublesome characteristics of fever dreams may be associated with negative moods brought about by sickness. Some reported themes of fever dreams include:

  • Images of objects melting or on fire
  • Feelings of unbearable heat
  • Being surrounded by lava
  • Recurring nightmares we experienced during childhood.
  • Frequent switches from a positive scenario to a negative scenario
  • Distorted figures or bodies with enlarged arms and legs
  • Unfamiliar or oversized creatures
  • Claustrophobia or the inability to breathe
  • Feelings of helplessness and weakness
  • Vertigo
  • Images of darkness spreading

These strange dreams can be jarring, especially if you find it hard to return to sleep after waking up from a recent fever dream.

Fever Dreams vs. Lucid Dreams

Fever dreams are often compared to lucid dreams, but they are actually quite different. The only similarity between the two is their extreme detail and high dream recall.

Lucid dreams are occasionally used as a tactic against nightmares like fever dreams. A lucid dream is defined by the sleeper being aware of their dreaming state. Hence the reason some people use them to overcome certain fears they feel during nightmares. Like fever dreams, lucid dreams are notably vivid. Some people even learn to control their lucid dreams to practice facing struggles or fears they encounter in real life. Other benefits include anxiety relief, enhanced creativity, and sometimes refined motor skills—all of which seem compromised during a fever dream.

Although fever dreams are memorable, they typically induce feelings of helplessness and confusion. On the other hand, lucid dreams provide comfort because sleepers learn to recognize that what they experience is not real. Also unlike lucid dreams, there are no particular benefits to fever dreams and most sleepers describe them as stressful nightmares rather than an anxiety-relieving practice.

Can You Prevent Fever Dreams?

There is no foolproof way to prevent fever dreams or dreaming at all, for that matter. However, you can attempt to decrease your chances of a fever dream by taking efforts to regulate your body temperature. The following practices may assist in alleviating a fever:

  • Drink plenty of fluids throughout the day.
  • Get enough rest.
  • Take fever reducers (ibuprofen or acetaminophen) as recommended by a medical professional.
  • Only consume easy-to-digest foods.
  • Bathe in lukewarm water.
  • Try to stay cool—do not pile on blankets or bathe in abnormally cold water.


Can you have hallucinations from a fever?

High fevers affect brain function and sometimes cause hallucinations. They typically occur with a fever of 103 to 106 degrees Fahrenheit, and they are most common in children and elderly people. Hallucinations are sometimes confused with fever dreams. Although they may feel the same, hallucinations only happen during consciousness.

Can fever dreams be good?

Having a fever doesn’t guarantee a night of nightmares and poor sleep. However, vivid nightmares while your body is at an elevated temperature are referred to as fever dreams. You can still have good dreams if you have a fever, but most people don’t refer to normal dreams during illness as “fever dreams” because they aren’t anything unusual.

Is it good to sleep with a fever?

Yes, it is good to get sleep when you have a fever. Rest is one of the most beneficial ways to treat fever. Although our symptoms seem to worsen while asleep, it actually speeds up the healing process. During sleep, our body not only restores white blood cells but adequately replenishes the energy our immune system depletes to fight off viral or bacterial infections.

Is it bad to stop a fever?

While unenjoyable, fevers are beneficial because they help your body combat illness and infection. You want a fever to naturally “break” itself, but sometimes fever reducers are necessary to ease unpleasant symptoms while your body tries to recover.

So to put it simply, you don’t want to “stop” a fever because the fever itself isn’t bad or dangerous, you want to ride out the fever so your body has ample time to recover from unwanted invaders. However, you can use fever reducers to make symptoms more bearable.

At what temperature should an adult go to the hospital?

If your fever rises to or above 103 degrees Fahrenheit, call your doctor. 103 degrees is considered a high-grade fever and is not meant to be sustained for long periods of time. If any of the following symptoms accompany your fever, it is best to go to the hospital: skin rash, stiff neck, consistent vomiting, abdominal pain, extreme sensitivity to light, difficulty breathing, chest pain, or seizures.


Fevers are normally the result of an infection. They are a natural part of illness and should not warrant worry unless they peak higher than 103 degrees. Even though fevers are useful for fighting infections, they can cause unwanted side effects like fatigue, body aches, irritability, and fever dreams. Perhaps the most frightening of these effects are fever dreams. Fever dreams are almost always composed of strange themes and eerie characters but like every other symptom, they will subside with infection.

Fever significantly impacts our brain function, so it may not be possible to control or stop these vivid dreams. If you have a fever, we suggest taking any prescribed medicine, staying positive, keeping cool, and getting plenty of rest—even if the extra sleep time does result in unpleasant fever dreams. Progressively, you will return to your core body temperature and achieve peaceful sleep.

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