When you heal the emotional wounds from your past, you release the negative feelings those wounds caused you to hold onto. 

The mind controls everything the body does.  The mind made a mistake one day and thought something pretty harmless was a bacterial or viral invader.  It decided to always react to that same invader every time.  We can change that!

Your mind learned to be afraid of whatever causes you fear in a single moment.  It can unlearn that fear reaction in a single moment as well.