Why Sleeping with a Fan On Might Be Harming Your Health
A doctor has warned that sleeping with a fan running all night could lead to coughing fits, chest discomfort, and painful muscle tension.
US-based physician Dr Naheed Ali explains that while fans are often used to stay cool, especially during heatwaves, they can quietly strain the body. Constant airflow can irritate the throat and airways, while also reducing blood flow to muscles, he says.
Hidden Risks, Especially for Allergy and Asthma Sufferers
For those with allergies or asthma, the risks may be even more serious. Fans can circulate dust, dirt, and other allergens through the air, making symptoms worse.
“People with asthma allergies often wake with extra chest tightness after a night with the fan on,” Dr Ali noted.
His comments come just as parts of the UK prepare for a potential heatwave, with temperatures forecasted to hit up to 30°C by Thursday, according to the Met Office.
Dryness and Irritation in the Airways
While fans can help people get to sleep—since the ideal room temperature for rest is between 16°C and 18°C—Dr Ali cautions that prolonged exposure to moving air can dry out the nasal passages and throat.
“The steady airflow of the fan can leave the nasal passages and throat uncomfortably dry by morning,” he told LADbible.
Dry air can lead to thicker mucus in the nose and sinuses, and increased phlegm in the throat, which can cause congestion and discomfort.
“A dry airway produces thicker mucus, which can trap allergens and irritants close to sensitive tissue,” Dr Ali explained. “Over time, this may trigger coughing, a scratchy voice, or clogged sinuses that linger throughout the day.”
For allergy sufferers, the moving air keeps particles like lint, pollen, and pet dander in circulation, allowing them to reach deeper into the lungs while you sleep.
Muscle Tension from Overnight Cooling
Another lesser-known effect of fan use is muscle stiffness. According to Dr Ali, prolonged exposure to cool air on muscles and joints may slightly reduce tissue temperature.
“Cool air against muscles and joints for seven or eight hours can cause a subtle drop in tissue temperature,” he said. “The chilled muscles tighten as a natural defense, and that tension may persist until a warm shower or gentle stretching restores normal blood flow.”
How to Use a Fan More Safely at Night
You don’t necessarily need to stop using a fan altogether. Dr Ali offers a few practical tips to reduce the downsides:
- Use a timer so the fan shuts off after 90 minutes—roughly one sleep cycle.
- Aim the fan away from the bed, preferably toward a wall.
- Keep bedding clean to minimize airborne dust.
- Keep a glass of water at your bedside in case your mouth or throat becomes dry.
“These small adjustments let the fan cool the room without increasing discomfort in the airways or joints during the full night,” Dr Ali added.
NHS Advice for Managing Heat at Home
The NHS recommends keeping your home cool during hot weather by keeping windows shut during the day and opening them at night when it’s cooler outside.
This advice comes as the UK faces the possibility of record-breaking heat, with pollen levels expected to remain “very high” across much of southern England and Wales.
Hay Fever Precautions During High Pollen Levels
Allergy UK advises hay fever sufferers to stay indoors as much as possible, and to take extra steps to prevent pollen from spreading indoors. These include:
- Showering and washing your hair regularly
- Removing your outer layer of clothing when coming inside
- Avoiding contact with your eyes and face
These simple precautions can help minimise discomfort during high pollen days, especially when heat and allergens are both at their peak.