What’s the verdict?
So, should you sniff or blow your nose? If you have mucus in the nose, it is probably best to sniff it. Your body has had millions of years of evolution to figure out what it’s doing. The natural direction snot moves is inwards. Doctors therefore always advise that it is a better choice to sniff rather than to blow your nose.
When you blow your nose you might push the mucus, including the bacteria, into your sinuses. This could do damage to your sinuses and cause a congestion or infection.
Blowing your nose, while more polite, is not a healthy choice. It might make your nose temporarily clear, but if you have a cold or allergies, a lot of the blocking is not from snot but from swelling of the lining. So, blowing it out won’t really help anyway.
If you must blow, then do it gently and with one nostril. The lining inside your nose is very thin and vulnerable. Use tissues instead of hankies and don’t forget to wash your hands afterwards.