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Brain Fog - What are the symptoms, causes, treatments, and COVID 19 medical effects on brain health?

Posted by Callie Torres
October 21, 2020
brain fog

Brain fog is a set of symptoms that many individuals experience. Although it is not a true medical condition, its symptomology make it a frustrating and exhausting occurrence. Brain fog may also be referred to as fuzzy-headedness, mental fatigue and Clouding of consciousness. It includes a long list of similar brain symptoms such as forgetfulness, haziness and poor concentration and it may be caused by a myriad of different underlying conditions.

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  1. What are the symptoms of Brain Fog?
  2. What causes Brain Fog?
  3. What is Covid 19 Brain Fog?
  4. Is there a simple treatment for this fog?
  5. Can my memory and cognitive function be affected?
  6. How long does it last?
  7. What causes the fogginess after eating?

What Health Symptoms Are Associated With Brain Fog ?

Symptoms of brain fog may include:

  • Forgetfulness
  • Cognitive decline
  • Fuzzy thinking
  • Feeling tired
  • Haziness
  • Poor concentration
  • Memory problems
  • Inability to focus
  • Difficulty in problem-solving

What Causes The Fog Feeling?

There are numerous different underlying disorders that could affect the brain and cause brain fog in subjects. It could be as simple as lack of sleep or as complex as a medical disorder, dietary deficiency, or other cause like chronic fatigue syndrome (CFS). Some example causes include:

  • Stress- Everyone experiences stress from time to time. However, chronically elevated stress levels can cause an increase in the body's stress hormone, cortisol. Cortisol can have many detrimental effects in the body including affecting memory, cognitive function and increasing brain fatigue and fog in subjects.

  • Lack of Sleep- Depending on your schedule, it may be difficult to increase the number of sleeping hours. However, lack of sleep may be one of the easiest remedies to help brain fog in subjects and is an important component of overall health. Although the recommended number of sleeping hours for adults may vary from person to person, it is important to find how many hours are necessary for you and your brain to reduce fog.

  • Diet- Poor diets, or lack of dietary variance can lead to vitamin deficiencies which is harmful to your health. Low levels of important vitamins like B12, has been shown to contribute to brain fog. Additionally, unhealthy diets may contain pro-inflammatory foods that upset the hormonal balance of the body and brain causing chronic fatigue and fog. Some people find that issues with their digestive system and grains may cause problems. There are at home tests such as, Everlywell, that help to identify food sensitivities. This could potentially reduce the level of fog, improve cognitive function, and promote overall health.

  • Medications- Many common medications such as benzodiazepines, beta blockers, and pain killers are known to cause brain fog. It may be as simple as lowering the dose or switching to another medication with a different mechanism of action to reduce brain fatigue and fog.

  • Chronic Fatigue Syndrome (CFS)- Brain fog may be a symptom of chronic fatigue syndrome. Other symptoms of CFS occur outside the brain and include difficulty sleeping, persistent fatigue, changes in cognitive function, muscle pains, and depression. If you are concerned about having chronic fatigue syndrome, it is recommended discussing this with a doctor.

  • Menopause Or Other Hormonal Changes- Fluctuating hormones in women during pregnancy, menopause, or Cushing's syndrome can cause brain fog. It may simply take time for hormone levels to balance on their own, or it may require the help of a doctor who can diagnose with a test and then medically manage the problem and improve your health.

  • Medical Conditions- Certain medical conditions that affect health can cause brain fog. Low levels of thyroid hormone in the body, hypothyroidism, can cause fog and other mental slowing symptoms. Many other disorders such as, multiple sclerosis (MS), cancer, head injury for example, may also affect the brain and cause fog. In addition, mild Dementia, Alzheimer will also alter Perception.

  • Mental Health Conditions- Many other health conditions that affect the brain, like depression, can also have brain fog as a symptom. Another possible cause of fog is attention deficit disorder (ADD). ADD (and ADHD) can cause the brain to have difficulties with cognitive thinking including fog. A psychologist or psychiatrist doctor may suggest remedies for the fog if it is associated with a mental health condition.

  • Heavy Metal Exposure- Exposure to heavy metals like mercury, lead, or arsenic has been known to affect the brain and cause fog, dizziness and confusion. Lead can be found in paint of older homes and toys which can be accidentally ingested. A doctor can perform a simple blood test that can check for levels of heavy metals.

  • Chronic Infection- Some infections can persist for long periods of time and become chronic. Fungal infections, like Candida, can persist for months or years. Chronic infections lead to chronic inflammation which is detrimental to the brain, cognitive function, fog presence, mental changes and overall health. If there is concern for chronic infections, a doctor may run a simple tests that check for the presence of infection.


woman with brain fog at doctor


chronic fatigue syndrome


What is Covid brain fog disease and it's cognitive symptoms?

COVID-19 can have long-term impacts on multiple body systems and organs. Some persistent symptoms in the so-called "Covid long haulers" include:

  • general fatigue
  • body pains
  • inability to exercise
  • headaches
  • difficulties in sleeping

These issues could be the result of long-term damage to an individuals lungs, kidneys, heart, or other body organs. The damage to these organs, or even just the symptoms caused by the organ damage, can impair cognitive learning and memory, resulting in brain fog. For example, how well could a person concentrate if they have been awake for the better part of the night and have a headache? The medical and scientific community is still looking into possible causes for lingering brain fog that occurs after COVID-19. Several plausible causes have been identified by researchers, including:

  • Lung injury causing chronic damage to the lung tissue leading to a lack of oxygen
  • Inflammation wreaking havoc throughout the entire body including brain cells
  • Swelling of the small blood arteries in the brain potentially leading to decreased blood flow
  • A post infectious autoimmune illness in which the immune system does not function properly, such as Chronic Fatigue Syndrome (CFS)

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Is there a simple Brain fog treatment to help with this foggy feeling In my brain?

Unfortunately, there is no simple single treatment for brain fog. Instead, treatment is usually aimed at correcting the underlying disorder if possible. This may be simple in the case of vitamin deficiency or medication side effect which has a straight forward treatment. However, when the underlying cause is unknown, getting rid of brain fog may be very challenging. There are a few different initial changes one can make if the cause of brain fog is unknown. These include:

  • Getting more sleep -  Stick to a sleep regimen getting a regular healthy number of hours each night to promote good brain health.

  • Eating a healthier diet- Eat plenty of fruit and vegetables ensuring all vitamin requirements are met.

  • Trying to lower stress levels- Stress reducing activities like meditation or yoga may help lower stress hormones which negatively impact the brain.

  • Getting a blood test that will check hormone and vitamin levels- A simple blood test will help pinpoint a problem if there is an underlying health issue that is affecting your brain.

  • Discussing common medication side effects with your doctor- If you are on multiple medications or started a new medication, tnen brain fog and other mental symptoms may be due to a medication side effect. Discuss the symptoms with your doctor to explore this possibility and treatment.

If brain fog persists and is affecting your daily activities, it may be time to discuss the issue with your doctor. They will be able to further evaluate a possible medical cause of brain fog, such as chronic fatigue syndrome (CFS), and hopefully correct the situation and find a treatment.

Medical theories have been discussed that link brain fog symptomology with a COVID-19 post-viral syndrome in a letter to the editor by Perrin et al. in Elsevier published in June 2020 (1).

Many subjects infected with COVID-19 go on to develop brain fog among many other physiological symptoms long after their acute infection has passed. In some subjects, post-viral fatigue may last long enough to be classified as chronic fatigue syndrome/myalgic encephalomyelitis (CFS/ME) syndrome. Other symptoms of CFS/ME include persistent fatigue, depression, diffuse muscle pains and non-restful sleep. One hypothesized pathway in which COVID-19 and similar viruses cause CFS/ME is through disturbance of lymphatic drainage in the brain. The lymphatic drainage in the brain normally passes through the cribiform plate of the skull into the nasal mucosa. However, in CFS and perhaps after infection with COVID-19, the drainage is blocked causing a build up in the lymphatic fluid in the brain and lung. If COVID-19 affects this drainage pathway in the brain or one very similar, it could also explain why some individuals infected with COVID 19-19 lose their sense of smell. In CFS/ME, the inadequate drainage of lymphatic fluid in the brain leads to an accumulation of pro-inflammatory molecules termed cytokines. The abundance of inflammatory molecules may be the cause of symptoms like brain fog, fatigue, disrupted sleep etc. in CFS.

Perrin et al. discuss that potential use of osteopathic manipulative medicine lymphatic drainage techniques to try and combat the lingering lymphatic fluid and pro-inflammatory cytokine accumulation in the brain thus lessening the symptoms of CFS, cognitive difficulties, and fog in subjects.

Are There Ways That This May Affect My Memory And Cognitive Function?

The short answer is yes brain fog can affect memory and cognitive function. Fog makes it difficult to think clearly. This may affect both the current cognitive function of the brain causing difficulty with problem solving for example, as well as hindering memory recall causing fuzzy headedness. If symptoms other than fog are present and persistent, it may be time to consider a cause like chronic fatigue syndrome, that is contributing to cognitive difficulties.

young woman with clouding of consciousness


mental confusion


How Long Does This Last?

Brain fog may last any amount of time ranging from a few minutes to years. Since the mental fog is a symptom rather than a true disorder it is important to find the underlying cause of the fog. Working with a doctor and having a test performed may be the easiest way to find the cause. Even when the cause of fog, like chronic fatigue syndrome, is found it might not be so simple to find a treatment. Some recommended changes to try and alleviate brain fog and return to normal cognitive function are mentioned in another section of this article.

What Kind Of Doctor Should I See If I Have Clouding of Consciousness Associated Cognitive Thinking And Perception Problems?

Patients should seek help and schedule a consultation at a medical center or with your Primary care Medical Dr. for initial patient care.

What causes Brain fog after eating?


If you are experiencing brain fog after eating, then there are a number of potential etiologies that could be the cause, including:

1. Food allergies and sensitivities (intolerance):

Food allergies and food sensitivities (intolerance) have been identified as a cause of Brain fog. Food allergies and food sensitivities are both inflammatory responses that people may have to different food ingredients. This is very complex and somewhat controversial topic and should first be discussed with a Primary care doctor first. Many times, patients may then be referred to a Gastroenterologist or Allergist/ Immunologist for further evaluation.

2. Gluten sensitivity:

Gluten is present in many types of food and is most commonly associated with Wheat. Celiac disease has been identified as a genetic disorder that is present in 1% of the world’s population and is directly due to gluten ingestion. Reports reveal that 5% to 6% of individuals have Gluten sensitivity which equates to about 18 million people in the USA. Celiac disease and Gluten sensitivity are underdiagnosed problems. More information about celiac disease may be found here and here.

3. Blood sugar disorders such as reactive hypoglycemia:

Reactive hypoglycemia is a drop in blood sugar levels that usually occurs roughly 4 hours after eating. It has been associated with symptoms such as confusion and lightheadedness. The exact cause of this issue is not distinctly known, but underlying health conditions should be ruled out by a Primary Care Physician. More information about blood sugar disorders may be found here.

4. Food additives:

Substances such as Monosodium Glutamate (MSG) have been associated with brain fog symptoms such as dizziness, lightheadedness, headache etc.

5. Artificial sweeteners:

Sweeteners such as Aspartame have been the subject of debate for many years. There is still much controversy in this area. Elimination of this from one’s diet may be worth discussing with a primary care Physician.

6. Dehydration:

Reports reveal that a 2% decrease in water to the brain can cause a multitude of symptoms including brain fog, fatigue, poor concentration, and headaches.


Perrin, R., Riste, L., et al. (2020, June 26). Into the looking glass: Post-viral syndrome post COVID-19. Retrieved October 13, 2020, from

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Posted by Callie Torres

Callie Torres is a Captain in the United States Air Force and a chief resident at Wash U/Barnes Jewish Hospital in St Louis. She is a freelance writer with many published medical articles as well as multiple peer-reviewed medical publications

Topics: Medical Practice Medical Conditions

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