Doctors Warn 4 Fan-Sleep Side Effects as Heat Waves Drive Overnight Use

1 articles · Updated · The Independent · Jul 25

Doctors say sleeping with a fan on all night can worsen four common problems—allergies or asthma, muscle stiffness, congestion, and dry skin or eyes—rather than simply making hot nights more bearable.
Constant airflow can stir up dust, pollen and pet dander, while also drying the nose, mouth and throat; that can trigger coughing, wheezing, sore throats, sinus headaches and extra mucus production.
Direct cool air on one area for hours can leave sleepers with a stiff neck or sore muscles, especially when the body stays still overnight.
Doctors say fans can still be used if they oscillate or point away from the body, the room stays at 30% to 50% humidity, and fan blades, floors and HVAC filters are kept clean.
The guidance comes with a limit: fans move air across the skin to help sweat evaporate, but they do not actually cool the room and are not thought to cause long-term harm.