The Real Reason Fevers Can Give You Weird Dreams

Dreams are among the greatest mysteries left to humanity. Researchers have a rough idea of where in the brain dreams originate and how they affect us, but they're still not sure as to why we start dreaming or why people dream in different ways. What they do know becomes even murkier when they focus on fever dreams. A new set of variables throws everything they know in the air, leaving many people wondering why fevers give us strange dreams in the first place and why they're so different from normal dreams.

Healthline defines a fever dream as any intense dream, usually negative and strange in nature, that occurs in someone with a fever. These usually occur in the REM (rapid eye movement) phase of sleep. It is possible to experience a dream — regular or fever-induced — during any sleep phase, but knowing when a fever dream is most likely to occur still doesn't explain why some people have them or why they're so different from regular dreams.

Researchers still aren't sure why fever dreams occur

As the Sleep Foundation explains, fever dreams differ from standard dreams in a few key ways. One of those differences is the emotional intensity of the dream. Researchers aren't sure why, but fever dreams are often vivid and negative with an emotional impact that sticks with a person after they wake up.

A 2020 study published in Frontiers in Psychology found that fever dreams were also far more likely to involve the topics of illness or temperature control than one's standard dreams. The researchers concluded that this could be evidence that dreams, particularly fever dreams, play a role in how we process events like illness. In other words, our mind tries to understand why our bodies feel so awful and its best method is by exploring the situation in vivid dreams.

A second hypothesis offered by the Sleep Foundation is that the body's increased temperature changes the way the brain functions. There aren't currently any studies on this theory, but it is one that researchers have put forward and will likely investigate as a way to understand the continuing mystery of human dreams.