For years, dramatic warnings about sleeping with a fan running overnight have spread online, often claiming that the habit could be dangerous or even deadly. Images of people sleeping beside fans are frequently paired with alarming messages telling everyone to stop immediately. However, the reality is much less frightening. While sleeping with a fan is not completely without possible downsides, there is no scientific evidence that a normal household fan can cause suffocation, oxygen loss, or the so-called “fan death” that has become a popular myth.

The idea of “fan death” became widely known through a Korean urban legend claiming that sleeping in a closed room with an electric fan could be fatal. Some versions suggested that fans remove oxygen from the room or create dangerous conditions while people sleep. Scientists have repeatedly rejected these claims because fans simply move air around; they do not consume oxygen or change the basic composition of the air. For most healthy people, using a fan overnight is considered a safe and common way to stay comfortable while sleeping.

Although fans are not dangerous in the way viral warnings suggest, they can create certain problems for some people. Constant airflow can dry out the skin, eyes, nose, and throat because moving air increases moisture evaporation. Some people may wake up with a dry mouth, irritated eyes, a scratchy throat, or a mild cough. These effects are usually uncomfortable rather than harmful, but they can become noticeable for people who already struggle with dryness or sensitivity.