Even Still
Even if you don’t have any issues with dust and pollen, and sleep with your eyes tightly shut, you can still be affected by a fan. The constant air is going to dry out your nasal passages, which can have a serious impact on your sinuses.
Muscles
If you leave the fan on anywhere near your body, you might find that you wake up a little sore. That’s because the air blast from fans can actually have a negative effect on your muscles, and leave them battered and fatigued.