Autonomic Dysfunction

From the National Institute for Neurological Disorders and Stroke, in the U.S.   LINK

  • Dysautonomia refers to a disorder of autonomic nervous system (ANS) function.
  • Most physicians view dysautonomia in terms of failure of the sympathetic or parasympathetic components of the ANS, but dysautonomia involving excessive ANS activities also can occur.
  • Dysautonomia can be local, as in reflex sympathetic dystrophy, or generalized, as in pure autonomic failure.
  • It can be acute and reversible, as in Guillain-Barre syndrome, or chronic and progressive.
  • Several common conditions such as diabetes and alcoholism can include dysautonomia.
  • Dysautonomia also can occur as a primary condition or in association with degenerative neurological diseases such as Parkinson’s disease.
  • Other diseases with generalized, primary dysautonomia include multiple system atrophy and familial dysautonomia.
  • Hallmarks of generalized dysautonomia due to sympathetic failure are impotence (in men) and a fall in blood pressure during standing (orthostatic hypotension).
  • Excessive sympathetic activity can present as hypertension or a rapid pulse rate.


  • National Dysautonomia Research Foundation  LINK
  • Dysautonomia International  LINK
  • Dysautonomia Youth Network of America

 Orthostatic Hypotension is Common – especially with Increased Age

  • It becomes increasingly important, as the decades go by, to be aware of the possibility of orthostatic hypotension
  • the symptom people will generally notice is feeling “dizzy”, light-headed and/or weak when they stand up. It may be mild, or may be severe enough that the person “blacks out” and collapses. Serious injury can result.
  • the symptoms will be milder or worse in different situations, different days. Something to watch out for is when the background tone of the nervous system is less, and so the blood pressure tends to be lower than at other times – such as when relaxing, sleeping, napping, after a large meal. In these situations, there is more likelihood that the blood pressure may not adjust rapidly enough to the needs of standing.
  • when people stand, the blood pressure normally adapts very quickly, as you need more blood pressure when you stand than when lying or sitting. This is so that the pressure is enough to keep the brain well supplied with blood flow and oxygen.
  • there are a number of medical conditions or situations than can make this more likely to become a problem. However, often no specific cause can be found and the explanation simply seems to be that the speedy response of the nervous system has slowed.
  • common factors that may be involved are many, and include:
    • medications that lower blood pressure (whether medications intentionally taken to reduce blood pressure or medications taken for other reasons but which can have the effect of lowering blood pressure)
    • diuretic medications, through reducing blood volume
    • anything that causes diuresis (urinating out more water than usual), such as certain herbs, alcohol intake, a drop in insulin level – e.g. from under-eating or from shifting to a low carbohydrate diet (see below)
    • sodium intake that is too low for that particular person, in their situation
    • hot weather, hot indoor temperature, fever
    • dehydration, through reducing blood volume
    • autonomic diabetic neuropathy – damage to the nerves is common in diabetes and this damage can onset even before the diabetes has been diagnosed. In fact, the damage to the nerves can begin in during the pre-diabetic state, which can go on for many years before the blood sugars become high enough to meet the diagnostic criteria for diabetes. The nerve damage, called “diabetic neuropathy” can be in many forms, but damage to the autonomic nerves is one form. An example of this is diabetic gastroparesis. (More on diabetic neuropathy in it’s various forms can be found elsewhere on this web site.)


NOTE: There are changes in diet or eating patterns that may have significant and even rapid effects on your blood pressure.

  • a major increase or decrease in your intake of sodium (present in the diet mostly as salt, but the salt may be evident or not obvious). When people switch to a “clean” diet or cut out most processed foods, often their intake of sodium can actually become quite low if they are not using salt in cooking or at the table (or salt-containing condiments such as soy sauce). A drop to a low intake of sodium can be a real problem for anyone with a tendency for low blood pressure or orthostatic hypotension or autonomic dysfunction. (Intentional lowering of sodium intake for a medical reason, under aware medical supervision, is not what I am referring to here.)
  • if there is voluntary or involuntary fasting or very low food intake.
  • a dietary change that lowers insulin demand, and thus over time lowers blood insulin levels – particularly when up to that point blood insulin levels have been high over time. For example, low carbohydrate diets (of various sub-types, including LCHF), very low glycemic index diet, ketogenic diets (therapeutic or “nutritional” ketosis).

It is very important to be aware that people on, or transitioning to, a low carbohydrate diet become more prone to postural hypotension and to lowered blood pressure in general.

Changing from a “normal” or “usual” North American dietary pattern to a low carbohydrate dietary pattern causes changes to sodium handling in the body. This is particularly notable in people who have insulin resistance, and so have high blood insulin levels over time. High blood insulin levels promote retaining sodium in the body, which promotes higher blood volume, edema and higher blood pressure. When a low carb diet is eaten, the need for insulin drops quickly and the blood levels of insulin start to go lower.

As the insulin levels drop, the retention of sodium falls. As the sodium leaves the body in the urine, water is urinated out with it. People starting a low carb diet often notice a high amount of urine output in the first days and even the first week or so. This loss of retained body sodium and the accompanying water shows up as less edema, quick loss of body weight as water in the initial days and weeks (can often be 2 – 8 pounds or more of the initial weight loss). There can be a quick lowering of blood pressure.

This will not by itself cause the blood pressure to go too low. However, many people have other conditions or situations that may have an additive effect and then the blood pressure can go too low – either generally too low or showing up as episodes of low blood pressure upon standing up (or other situations such as passing stool or urinating). Some people will have medical conditions that make them more susceptible to blood pressure that is too low or drops episodically  – for example autonomic nervous system dysfunction or conditions pre-disposing to postural hypotension. Certain medications can also predispose to low blood pressure.

You might easily think of these medications because you know you are taking them specifically to improve your known hypertension. On the other hand, you might be on a medication that tends to lower blood pressure, but not realize it because the medication is being used for another purpose, not specifically because you have any history of high blood pressure. Examples of this would be diuretic medication used to lessen edema, beta-blockers used to help heart rate, or nitro-patch to control angina.

  • For any person who is considering any diet change that may bring a substantial change in their metabolism, careful consideration of their medication and their over-all medical situation is very important prior to deciding on and starting the diet change. Certain diet changes may not be wise for certain people. In other situations, it may be indicated to reduce certain medications just prior to, or at the start of, major diet changes. Monitoring blood pressure at different times and situations in the day/night may be particularly important in the first days and weeks, along with careful thought and attention to possible symptoms, such as light-headedness or a feeling of weakness or “dizziness”.
  • Since it is not possible to detail all the various possible dietary changes which might bring these concerns in which various medical conditions or health situations, I strongly recommend you discuss these topics with your health professional before initiating changes in your diet pattern.

POTS – Postural Orthostatic Tachycardia Syndrome

This article gives a good over view, though this syndrome affects many adults, not just teens. It was written for a parenting magazine, which explains the focus on the experience regarding teens.

“The teen disease you’ve probably never heard of”

“Postural Orthostatic Tachycardia Syndrome is a form of dysautonomia (when the autonomic nervous system malfunctions) that affects a large portion of teens. Symptoms may include heart palpitations, extreme fatigue, brain fog, nausea, headache, light-headedness, heat intolerance, exercise intolerance, insomnia, headaches, gastric problems, chronic pain, and near-fainting or full fainting spells, especially upon standing upright or walking. The symptoms are “severe enough to limit daily functioning” says Dr. Blair Grubb, a leading Postural Orthostatic Tachycardia Syndrome specialist in the country. Many compare the quality of life to that of having congestive heart failure.

There is no cure for it, but a variety of medications and lifestyle modifications help alleviate symptoms. The first primary therapy is extra fluids and extra salt to increase the blood volume, as most people with suffer from hypovolemia, or low blood volume, which increases their orthostatic intolerance.”

LINK  to the full article, by Danielle Sullivan, of New York Parenting

To learn more:

  • Standing up to POTS  A web site maintained by a parent. Extensive resources. Includes a mix of standard information and recommendations, along with ideas and recommendations of her own, which are not necessarily research-backed and may or may not be useful or even a good idea for any specific person to try. Links to Facebook pages for adults and for teens.
  • Rare Clinical Diseases Research Network article on POTS

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