Are you born with vagal response or viovagle synscope? and why would it just start happening? are there warning signs? is it caused by stress/anxiety

Vagal responses: Activation of the vagus nerve typically leads to a reduction in heart rate, blood pressure, or both. This occurs commonly in the setting of gastrointestinal illness such as viral gastroenteritis or acute cholecystitis, or in response to other stimuli, including carotid sinus massage, Valsalva maneuver or pain from any cause, in particular, having blood drawn. The extreme manifestation is syncope