Cold hands, a racing chest — the autonomic nervous system that regulates blood flow

Blood flows along differences in pressure. The force the heart pushes with, the resistance the vessels hold, the force the veins send back — these conditions change from moment to moment.

But who sets those conditions? In that place sits the autonomic nervous system. That is what this article is about.

Blood pressure is the product of two things

Blood pressure is not a mysterious number. It is set by how much the heart sends out and the resistance the vessels create — the product of the two. It is the basic equation of circulatory physiology.

So when the fine vessels at the periphery narrow, sending the same volume requires higher pressure. Blood pressure rises. Sometimes it is not that the heart has gone bad, but that the road has narrowed.

The blood coming back is a different matter

The heart handles the sending out. The coming back is shared among several forces.

A large share belongs to the calf muscles. With every step, the calf squeezes the veins and sends blood upward. So when the calf pump does not work well, pressure in the leg veins rises, and the legs feel heavy and swell. This is well established.

What happens when you sit for a long time has actually been measured, too. After a few hours of sitting, blood flow to the legs drops markedly and calf circumference increases. Posture changes flow.

What changes pressure moment to moment is breathing and posture. As you breathe, the diaphragm rises and falls, changing the pressure in chest and abdomen, and that change is laid on top of blood returning. (The rhythm breathing lays on the body)

The autonomic nervous system as a control panel

Here is the heart of it. What decides whether a vessel narrows or widens, whether the heart beats faster or slower, is the autonomic nervous system.

The sympathetic nerves go to the heart and to the vessels both. The cardiac branch quickens the beat; the vascular branch tightens the vessels.

But here is an interesting part. These nerves do not go out to the whole body uniformly. They are regulated separately by region. The sympathetic supply to muscle and the sympathetic supply to skin move differently from each other. The skin branch is not governed by the feedback device that monitors blood pressure.

Why does this matter? Because it means you cannot say simply that "when you get tense, these symptoms all come at once." Cold hands and a racing chest are not one switch being flipped so that both happen together. Each is regulated through a different path.

And yet some people do have them together

Still, in the consulting room I often meet people like this: hands and feet cold, chest racing, stomach uneasy — and every test normal.

It is hard to say they come together because the mechanism is one. As we just saw, the paths are separate. But among people whose regulation has been tilted one way for a long time, I often see this combination — that is the observation I hold from clinical practice, and it sits apart from established fact.

So rather than counting symptoms one by one, I look first at which way the regulation is tilted.

Then where does treatment look?

From this view, I use herbal medicine to change the conditions — to loosen what is clenched, drain what has pooled, lower a tension that has run high.

But flow and regulation are not the whole of the body. The body's conditions are set by several axes together — chemistry, metabolism, immunity, all standing side by side. Circulation is one of them, and in this article I have looked at that one. (What herbal medicine does)

If organic damage is suspected, I recommend imaging or other care first. If chest pain comes with it, if breath suddenly shortens, or if only one leg swells, that may be a different matter and you should be examined first.

But when "the tests show nothing and yet the body keeps struggling" — looking together at which way the control panel is tilted is one of the starting points of my practice.

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References

• Circulatory physiology: blood pressure is set by the product of cardiac output and peripheral vascular resistance — StatPearls (NCBI Bookshelf), 2023
• When the calf pump weakens and venous pressure rises, heaviness and swelling of the legs follow — Cardiology and Therapy, 2021
• The sympathetic nervous system regulates heart rate and vascular tone separately by region — Mayo Clinic Proceedings, 2009

Written by Dr. Heo Ji-young (PhD in Korean Medicine Pathology, Kyung Hee University · former Research Professor of Herbology, Kyung Hee University)