Brain fog is described as “cognitive dysfunction”, in areas such as thinking, remembering, concentrating, and reasoning to a level that interferes with daily activities. (1) According to Vanderbilt’s Autonomic Dysfunction Clinic, 80-90% of POTS patients report brain fog as a symptom. Vanderbilt describes brain fog as “difficulty thinking, concentrating, or paying attention; trouble remembering things; cloudy or fuzzy feeling in head; and having problems finding the right words.” According to Dysautonomia International ,this can occur even while patients are lying down or seated, which limits their ability to attend school or to work.
How Does POTS Cause Brain Fog?
When a person stands up, gravity naturally pulls our blood down into the lower half of our bodies.
In a healthy individual, the body is able to compensate for this and push blood back up to the heart and the brain. In POTS and other Dysautonomias, there is a malfunction in the body’s ability to do this (for a variety of reasons). As such, blood instead pools in the lower extremities. Simply put, there isn’t enough blood getting up to the brain.
In POTS, there can be two reasons why this doesn’t happen:
Low blood volume (there’s not enough blood, so it can’t reach all the way up)
2. Loose blood vessels (lack of constriction doesn’t push blood back up)
Dysautonomia is an umbrella term used to describe several conditions with one common cause- a dysfunction of the autonomic nervous system, or ANS. POTS (Postural Orthostatic Tachycardia Syndrome) and NCS (Neurocardiogenic Syncope) are the two most common forms of Dysautonomia.
What is the Autonomic Nervous System?
The autonomic nervous system controls all of your body’s “automatic” functions, such as heart rate, breathing, blood pressure, digestion, and temperature control. It is divided into the Sympathetic and Parasympathetic nervous systems. The Sympathetic functions are “fight or flight” and Parasympathetic are “rest and digest”.
How Common is Dysautonomia?
Dysautonomia is NOT rare- it impacts an estimated 70+ million people worldwide.
What are the different types of Dysautonomia?
There are more than 15 different dysautonomias (3). Two of the most common ones are POTS (Postural Orthostatic Tachycardia Syndrome) and NCS (Neurocardiogenic Syncope).
POTS (Postural Orthostatic Tachycardia Syndrome) is estimated to impact 1 out of 100 teenagers and, including adult patients, a total of 1,000,000 to 3,000,000 Americans. POTS can cause lightheadness, fainting, tachycardia, chest pains, shortness of breath, GI upset, shaking, exercise intolerance, temperature sensitivity and more (1).
NCS (Neurocardiogenic Syncope) is the most common form of dysautonomia. It can cause fainting spells that happen once or twice in your lifetime or multiple times every day. NCS is also called situational syncope or vasovagal syncope (2).
NCS (Neurocardiogenic Syncope), is single or multiple fainting spells.
OH (Orthostatic Hypotension), characterized by decreased blood pressure upon changes in position (sitting or standing).
IST (Inappropriate Sinus Tachycardia), characterized by sustained increased heart rate, regardless of position. Usually 100BPM+ at rest. (5)
AAG (Autoimmune Autonomic Ganglionopathy), is a rare condition in which the body’s immune system mistakenly attacks and damages certain parts of the autonomic nervous system. (6)
FD (Familial Dysautonomia), also known as Riley-Day Syndrome, is a rare inherited disorder that impacts nerves throughout the body. (8)
PAF (Pure Autonomic Failure), is a neurodegenerative disorder of the autonomic nervous system clinically characterized by orthostatic hypotension. (9)
MSA (Multiple System Atrophy), a rare condition of the nervous system that causes gradual damage to nerve cells in the brain. This affects balance, movement and the autonomic nervous system, which controls several basic functions, such as breathing, digestion and bladder control. (10)
BF (Baroreflex Failure), is characterized the loss of buffering of blood pressure and is characterized by volatility of the blood pressure and heart rate (7).
AD (Autonomic Dysreflexia), is a form of autonomic dysfunction associated with spinal cord injuries. Usually, when an AD attack occurs, there is an irritant impacting the person below the level of their spinal cord injury, and because their autonomic nervous system cannot process messages properly, this results in a severe spike in blood pressure, flushing above the spinal injury, nasal stuffiness and other symptoms. (4)
DAN (Diabetic Autonomic Neuropathy), is a secondary (to diabetes) form of Dysautonomia where nerves become damaged.
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