Why do I feel faint at the sight of blood?

Why do I feel faint at the sight of blood?

Dear dondo,
Syncope [pronounced sin-co-pee]: a sudden brief loss of consciousness

In the case of fainting at the sight of blood, syncope results from non-cardiovascular causes, particularly due to problems with the autonomic nervous system, which is responsible for many of our bodily functions, including regulating blood pressure, heart rate, and our responses to anxiety, fear and emotional stress. Vasovagal syncope, typically precipitated by unpleasant physical or emotional stimuli (eg, pain, fright, sight of blood), usually occurs when a person is standing upright. The feeling of fear or anxiety at the sight of blood is the cause of the onset of fainting:

* As the heart beats faster and stronger [a response of the autonomic nervous system to person seeing blood], it sends a wrong message that tells receptors in the heart's chambers that the ventricle is filled with blood.
* The receptors send a message telling the nervous system that blood pressure is too high. In fact, the ventricle is not full and the blood pressure is too low.
* When the brain receives the faulty message, it slows the heart rate and further dilates the blood vessels.
* The blood pressure drops even lower, less blood is pumped to the brain and the risk of fainting increases.

Sue...good luck

I dont know I was wandering the same thing my doctor says it is a comon thing I have hade the same problem whin I have to have a blood test

you have a week stoumach