Sanjay Gupta: Fainting a common problem

CNN medical correspondent Sanjay Gupta

(CNN) -- What could have caused President Bush to collapse Sunday while eating pretzels and watching a football game at the White House?

CNN's Paula Zahn talked to medical correspondent Sanjay Gupta on Monday to shed light on the causes of fainting.

ZAHN: Talk to us a little bit about what would cause the president to faint and what does a pretzel have to do with it, if anything?

GUPTA: It is actually a pretty common problem. Something that could occur when people are scared of something. Sometimes cramping in the intestines can do this. Sometimes violent coughing can do this.

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We are talking about vasovagal response. The name is not as important as what it does. What it is actually is a reflex -- in this case possibly brought on by heavy coughing, which can stimulate a nerve to stimulate the heart to lower the blood pressure and lower the heart rate.

A change in heart rhythm and dehydration could also possibly do it. Apparently, the president was feeling a little under the weather over the weekend -- that could have led to a little bit of dehydration. That in combination with the violent coughing episode surrounding eating the pretzel could have caused him to faint. It is a pretty common thing, and [doctors] see it a lot in emergency rooms and hospitals, but oftentimes it is just an isolated event and does not come back.

ZAHN: Run us through some of the tests that were done on the president to make sure this was nothing more serious than an isolated fainting spell.

GUPTA: One of the first things certainly is to make sure that his heart is OK, that he is not having a heart arrhythmia. The EKG [electrocardiogram] would be the test to rule that out. Certainly a blood test [is necessary] to make sure his blood sugar was up to speed and to make sure he did not become hypoglycemic -- that would be another test.

He is going to have to have a few other tests, I'm sure, over the next couple of days. I understand that he is going to the doctor Monday morning -- probably to get another quick checkout to make sure that his heart rate and blood pressure are up to par.

Again, [it's] a pretty isolated event. Just about everybody has some vasovagal episode in their lifetime. It does not lead to fainting in everybody, but certainly [it did] in this case, which happens to be the president. He did appear to pass out completely. He did get an abrasion on his left check and lower lip, so it does seem like he completely lost consciousness.

ZAHN: Is there any hereditary link? We do know that his father had a fainting spell once on an overseas trip.

GUPTA: No, there is not a hereditary link to this. It is truly related to a reflex within the body.