Hi RLR,

But I'm confused re: this vagal theory. If the vagus nerve innervates the PNS, rather than the SNS, then why doesn't my heart rate "slow" rather than "increase" during anxiety or palpitations -- if clearly it is anxiety relating to vagal stimulation? This confuses me, as I'd think that the vagus can "slow down" (& thus reduce palps) rather than the other way around?

Also, does this release of neurotransmitters & catecholamines (via anxiety or SNS stimulation) result in any longterm damage to vascular or endothelial structures/tissue? Ok, sorry to ask this but I know you can clarify well & my Nurse Practitioner isn't able to explain at all.

I typically have increased BP & HR when anxious/nervous & this must lead to chemical releases, which concerns me, as they may be stressing the lining of vasculature & thus damaging blood vessels via this response?

Does this make sense or am I misreading or a bit offbase? I realize anxiety is the body's warning but I can't seem to settle it down easily by exercise, deep breathing, etc. & therefore am still concerned re: this anxiety.

Lastly, is the vagus then involved when -- if I experience my higher heart rate/anxiety while working out, etc. -- if I then squat down (thus valsalva-style) I then lower my heart rate on my pulse meter (which I wear during workouts)? Also, if I measured my BP during this "squat down to relieve my anxiety/higher HR" it would then drop as well, yes?

This correlates w/ a drop in systemic BP during reclining & thus, the corresponding increase in HR & BP during other (upright or even standing) postural positions? In effect, postural changes affect BP/HR but... where then does vagal intervention play a role in postural movements (& therefore in the relief of higher HR/pounding heartbeats)?

Again, squatting whenever I'm anxious "immediately lowers my HR" & I feel much better but does this reduce my "anxiety chemical release" (or is this just making me "feel better") but not changing my physiological response at all -- or very much?

Thanks again very much sir.

Okay, the vagus nerve does not innervate the parasympthetic nervous system. The vagus nerve is a part of the parasympathetic nervous system, so the reverse of your impression is actually more accurate.

Your heart is stimulated by both the sympathetic nervous system and the parasympathetic nervous system that produce synergistic influence, sometimes increased sympathetic and sometimes more parasympathetic, but never simply one or the other.

The type of influence on the heart by the parasympathetic nervous system is traditionally one that reduces heart rate. In the instance of palpitations, they are not occuring as a consequence of rapid heart rate, but rather an inappropriate evoked potential or signal which travels along the nerve to all terminal points, one of which is the heart. You feel the sensation because the heart as a muscle responds to the signal much in the same way any other muscle in the body can twitch as a consequence of being stimulated by inappropriate nerve impulse.

The vagus nerve plays a critical role in the influences of gravity against body position by increasing or decreasing tone depending upon need to maintain perfusion to the brain. Increased vagal tone equates with higher BP, whereas lowered vagal tone naturally represents lower BP.

The physiologic effects of reclining are in no way similar to those associated with squatting down and approximating a valsalva manuever. Reclining or lying suppine increases parasympathetic tone and lowers vagal tone influence upon the vascular system as the effects of gravity against an upright body are lessened.

The valsalva approximation causes transitory changes in pulmonary circulation and cardiac stroke volume. It is these changes which support adequate perfusion to the brain. So depending upon precisely how you squat down, you can realize effects from the valsalva which would increase cardiac force and blood pressure, to the effects of vagal tone which tend to lower these characteristics depending upon the body's position relative to the force of gravity against it.

Pounding heart constitutes an increase in cardiac force as a result of baroreceptors in the internal carotid arteries providing feedback to the brain regarding changes in blood pressure. If for instance you engage in isometric exercises and lift a heavy weight for a period of time and then suddenly place it down, a significant change in blood pressure can occur that produces a sudden but brief decrease in BP. The baroreceptors in the carotid arteries respond with feedback to the cardiac center in the brain, which instruments increased cardiac force in order to quickly restore normalized BP. This is why some people feel momentarily lightheaded after lifting weights.


You're at no real risk of arterial damage as a consequence of stress hormones being circulated throughout your body. Only those with pre-existing risk factors raise concern with regard to stress.

Best regards and Good Health