What is a Fever Dream?

There’s never a convenient time to get sick. Coming down with something that involves a fever makes it even worse. A fever indicates the body is fighting an infection. By itself and within a moderate range (under 104 F), a fever itself is harmless. But the symptoms of a fever can make life miserable. Chills, sweating, achy muscles, and a lack of appetite are all common with a fever. A less common, but quite disturbing symptom can be fever dreams. These are abnormal and often bizarre or disturbing dreams. To fully understand fever dreams let’s dive into fevers, dreams, and how to two can collide.

What is a Fever?

A fever is the body’s natural response to fighting an infection. A fever raises the body’s normal temperature, which usually hovers between 97 and 99 F. A body temperature above 101 F is considered a fever. Most fevers will raise the body’s core temperature by two to seven degrees. It indicates the body is fighting something, usually a virus, bacteria, or infection. All of these instances involve pathogens entering the body. The pathogens are temperature-sensitive, so the body’s natural defense is to heat up. The elevated temperature inhibits many pathogens from multiplying in the body. Essentially, the heat kills off the illness.

Moreso, a fever also kicks the immune system into full speed, acting faster and more aggressively to fend off the illness.

Although uncomfortable, a fever’s purpose is to help kill the pathogens that are making the body ill.

Why do we Dream?

Everyone dreams, although it’s common to not recall dreams. Everyone experiences several dream cycles each night lasting between five to 20-minutes. The reason why our brains dream is still unknown, but we do know dreams can happen during any stage of sleep but the most likely to be remembered occur during REM sleep. In one study, participants said they could remember dreams during REM sleep about 82 percent of the time but only had a 50 percent recall rate for dreaming that occurred during non-REM sleep (NREM).

Studies indicate that the brain has access to memories during NREM sleep so dreams can involve people, places, and events that an individual has experienced in real life. The parts of the brain responsible for memory, however, seem inaccessible during REM dreams which may explain why vivid dreams during REM sleep involve non-plausible aspects like individuals flying, walking through walls, or conversing with fish.

While dreams can come in many forms, fever dreams are usually more bizarre, vivid, and oftentimes disturbing.

What Occurs During a Fever Dream?

Fever dreams are essentially nightmares an individual experiences while suffering from a fever. Even those who don’t usually experience nightmares may have a fever dream. In contrast to normal dreams, fever dreams tend to be intensely emotional, often times negative, and leaves the already ill individual disturbed by dreams they experienced. Some commonly described fever dream symptoms and topics include:

• Odd dreams that are often able to be recalled in specific detail.
• Spatial distortion like walls moving or caving in, oversized insects, or non-realistic creatures.
• An individual in a fever dream often feels threatened by someone or something in the dream. A huge dog, terrorist, inability to breathe, or vertigo are commonly reported.
• Repetition of events or movements is a theme in reported fever dreams with individuals reporting doing a specific action over and over or experiencing the same dream throughout the night.
• Almost all reported fever dreams have a negative association for the sleeper inducing stress, fear, or restlessness.
• Many recall being aware of dreaming while it was happening, suggesting fever dreams could include an aspect of lucid dreaming.

Thermoregulation, Stress, and Fever Dreams

The body naturally thermoregulates, meaning the brain keeps the body at a regulated temperature. However, during REM sleep thermoregulation is less efficient. The hypothalamus in the brain is responsible for body temperature. This is also the same part of the brain that is responsible for producing a fever when the body is fighting something.

Temperature significantly impacts sleep quality. Those with impaired thermoregulation show greater likelihood of insomnia and other sleep disturbances. As a fever raises the core temperature, sleep disruptions including fever dreams may occur. Research suggests the bizarre and distorted nature of fever dreams may be related to these higher temperatures. People suffering from a fever routinely display impaired cognitive abilities so it makes sense that impairment translates into sleeping behavior as well.

Nightmares occur more often in individuals who experience stress. While a fever causes stress on the body, this may be a reason why those with a fever can experience a fever dream.