Blowing the nose when it's blocked with mucus seems to be relieving when you're down with cold. But does it actually help relieve symptoms? And is it the right thing to do? Researchers say blowing the nose too hard could be dangerous. Sinus infection: According to recent study conducted at the University of Virginia cited in The Wall Street Journal when you blow your nose your generate 10 times more pressure than you do while coughing or sneezing. Sometimes the pressure generated can be so intense that the accumulated mucus may even propel into the sinus spaces and drainage passageways.