I’m never going to sleep with a fan on again…

2. You Experience Neck, Shoulder, or Muscle Stiffness
If you wake up with a stiff neck, sore shoulders, or tight muscles, the fan could be contributing. Continuous airflow—especially cool air—can cause muscles to tense slightly during sleep. Over several hours, this tension may lead to soreness or stiffness in the morning.

People who are more sensitive to temperature changes or who sleep in one position for long periods are more likely to notice this effect. A fan blowing directly on the body tends to make this problem worse.

3. You Feel Congested or Have Allergy Symptoms in the Morning
Fans don’t just move air—they also move dust, pollen, pet dander, and other allergens around the room. If you’re sensitive to airborne particles, sleeping with a fan on may worsen allergy symptoms without you realizing why.

Possible signs include:

Sneezing shortly after waking
Itchy eyes or throat
Increased mucus or postnasal drip
Even a clean-looking room can contain allergens that are kept in constant circulation by a fan running all night.