This refers to the blood vessels and whether they constrict or dilate (get narrower or wider).

Constricted Blood Vessels - in the arms and legs, they can result in cold hands and arms and cold feet.

Dilated vessels - this would be wider vessels that hold more blood. It can cause 'acrocyanosis' or blue legs (see the entry at the bottom of the table)

Too much sweating - hyerhidrosis. If it is local, it is usually the palms and soles (bottoms of the feet).

No sweating. This can cause a problem with dry skin, increase heat (hyperthermia and even vasomotor collapse in hot weather. It's important to keep cool, avoid exposure to heat.

It can happen everywhere or only in regions of the body, like the feet or hands or forehead. (Sudomotor means something that stimulates the sweat glands.)

Bloating, nausea, vomiting, pain, constipation, diarrhea

However, in one study, patients with POTS, neurally-mediated hypotension (NMH) or both POTS and NMH had upper GI symptoms. On follow-up, they found that the GI symptoms had improved with improvement in the orthostatic condition.¹³

Xerostomia - dry mouth.

Other autonomic symptoms not reported as being strongly associated with POTS or NMH: Delayed emptying of the stomach (gastroparesis) - sense of fullness after eating a little bit; problem with swallowing (dysphagia)

With autonomic dysfunction, there is often a change in the ability to regulate body temperature. A person will overheat when exercising or in hot weather or hot rooms. They can switch and be cold. The person may feel hot inside but the skin on their arms/hands can be cool or cold to the touch. Body temperature or their sense of temperature may be inconsistent with the room temperature. On the other hand, they can be more sensitive to cold and heat. (This is 'peripheral vasomotor dysfunction'¹⁴)

Changes in the pupil muscle and accommodation may be present and create symptoms of sensitivity to excessive glare or bright lights or poor night vision.¹⁴

The blood pressure is more variable, going up and down, more than it does it in people without POTS.¹⁰ There may also be difficulty palpating a pulse at the wrist when a person continues to stand or with the Valsalva maneuver.

There may be changes in how the skins feels things.¹⁴ There could be areas of increase sensitivity to repeated stimulation of skin. There can a sense of pain from things that do not normally cause pain (allodynia). There could be hyperpathia - which means there is an abnormal increase sense of pain from a stimulus that would be painful, like a pinprick. (autonomic nerve dysfunction)¹⁴

These are symptoms of autonomic dysfunction.¹⁴

People with POTs or CFS often have a condition called "acrocyanosis" - which means blueness.^{5,8,10,11, 15}  The legs turn colors with standing. These are "acral vasomotor" vasomotor changes due to the failure of the autonomic nervous system (ANS).¹⁴  (Changes in the skin due to the blood vessel changes).

They can turn blue (cyanotic) or be pale. They can be pink/red with standing for awhile. But when it is most extreme, they turn blue and the legs swell with standing up for a longer period of time. The blueness or redness could be solid or it might be blotchy (mottled).

The hands can also turn blue with standing up for a while. In some people, when they lie down, the color returns to normal and there is tingling or abnormal sensation until they return to "normal".