I was diagnosed with vasogal syncope many years ago by a cadiologist who happened to be a big authority on fainting. I get it from anything that stresses my body. Caffiene, exercising, dangerous situations. I did a tilt table study where they gave me a drug that stimulated a caffiene and my blood pressure plummeted and heart rate too. I was told by the doctor that vasogal meant the veins were not doing their job pushing the blood through. Two things I have found out have helped: do not rise quickly from a sitting position, and if feeling faint you need to breathe deeply and slowly. When you feel faint you tend to get nervous and hyperventilate, so slowing down your breathing can help and deep breathes get in more oxygen into your lungs. I have small veins so that may contribute to it. Following my rules and avoiding stimulants has made me free of fainting for many years. Vasogal syncope is a general diagnosis so it can have many different causes.