When you sneeze, the intrathoracic pressure in your body momentarily increases. This will decrease the blood flow back to the heart. The heart compensates for this by changing its regular heart beat momentarily to adjust. However, the electrical activity of the heart does not stop during the sneeze.

Is a sneeze the closest thing to death?

Although many superstitions associate sneezing with danger or even death, sneezing is just a natural reflex, much like itching and tearing. Most of the rumors about sneezing are not true.

How come when I sneeze I almost pass out?

Some people experience a phenomenon called “sneeze syncope.” Syncope (pronounced SIN-ko-pea) means fainting or passing out. When this occurs, the sneezer's heart rate and blood pressure drop so low that they can feel dizzy or even pass out.