HomeHealth articlescovid-19What Is COVID-19 Brain Fog?

COVID-19 Brain Fog - Causes, Symptoms, Diagnosis, and Treatment

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Brain fog is a cognitive impairment and a neurological symptom commonly reported by people with COVID-19. Read the article to know more.

Written by

Dr. Osheen Kour

Medically reviewed by

Dr. Arpit Varshney

Published At March 14, 2023
Reviewed AtMarch 14, 2023


Brain fog is a feeling experienced by a person post-COVID-19 (coronavirus), making them feel mentally slow and sluggish. It is a common feeling that a person goes through when they are sick. Brain fog is not a medical condition but a symptom caused by various medical conditions. It is described as a cognitive dysfunction that leads to poor concentration, memory problems, disturbed focus, and lack of mental clarity. COVID-19 brain fog mainly develops weeks or months after recovery from the long haul COVID. A person may have worsening pre-existing mental health symptoms, neuropathy, or spine injury that gets aggravated due to COVID. In addition, they can also have memory impairment due to aging, leading to a further decline in cognitive abilities. However, COVID-19 can trigger new cognitive impairment symptoms in a person of any age group.

What Are the Causes of COVID-19 Brain Fog?

COVID-19 brain fog can be caused due to both psychological and physiological factors. Researchers have found that the COVID-19 virus is neuro-invasive and thus attacks the brain tissues. The virus can cause neurological complications in people, such as encephalopathy and altered consciousness. In addition, it has also been found that due to long COVID, the cytokines, an inflammatory molecule secreted by the immune system surrounding the person’s brain post-COVID, encourage inflammation in the brain. The inflammation affects the communication of the neurons with each other and thus contributes to brain fog. Some researchers have also indicated that hippocampus and microstructural changes in the person’s brain due to COVID-19 can also lead to brain fog.

In addition, various other factors that may cause COVID-19 brain fog to include:

  • Dietary changes.

  • Depression.

  • Poor sleep quality.

  • Lack of physical activity.

  • Loneliness and isolation.

  • Various medications cause side effects.

  • Increased anxiety and stress.

What Are the Symptoms of COVID-19 Brain Fog?

Brain fog is a mental condition that makes a person fuzzy, slow, and mentally spaced out. The condition is not clinically diagnosed, but it is a general feeling of someone suffering from COVID-19. Therefore, the symptoms of brain fog include

  • The patient may have trouble concentrating.

  • Headache.

  • The patient may experience difficulty with memory and remembering things.

  • Confusion.

  • Lack of mental clarity.

  • Feeling out of space.

  • The patient may experience visual effects such as blurring of vision, floaters, and other visual disturbances.

A person can experience brain fog symptoms occasionally, which may be due to stress and poor sleep, or weeks or months after developing COVID-19 symptoms, such as fatigue, fever, and cough.

How Long Does Brain Fog Persists Post-Covid-19?

A person usually recovers from COVID-19 brain fog within six to nine months. However, people with already existing mental health problems, such as cognitive impairment and dementia, usually do not recover completely from brain fog. Since there is no cure for fast recovery from post-COVID, a person can only speed up recovery by making lifestyle changes and adopting healthy ones to boost the recovery process of nerves and the brain.

When Should a Person See a Doctor?

Brain fog often develops in some people post-long COVID conditions and may resolve as time passes. However, if a person experiences worsening these symptoms, they must consult the doctor. They should see a doctor,

  • If the symptoms are interfering with their daily life activities.

  • If it is getting worse day by day.

  • If the symptoms are quite concerning and cause noticeable distress in a person.

  • If cognitive impairment is severe and causing them depression, anxiety, and mental confusion.

How Is COVID-19 Brain Fog Diagnosed?

COVID-19 brain fog diagnosis is possible only if the condition is present for at least 12 weeks after initial COVID-19 symptoms. However, no diagnostic tests and tools are available to diagnose brain fog related to long COVID. Therefore, the doctor can only analyze the case through the symptoms reported by a person post-COVID.

What Are the Lifestyle Changes That Can Help Cure COVID-19 Brain Fog?

  • Limiting alcohol consumption and any other substance that can affect brain functioning.

  • Quit smoking.

  • Getting enough sleep.

  • Vitamin D supplementation also enhances nerve and brain function.

  • Exercising for 30 minutes daily can also improve brain health.

  • Improving dietary habits and eating healthy foods, including whole grains, nuts, fruits, vegetables, and beans, helps boost mental health, thinking, and memory.

  • Exercising memory and mind by reading newspapers and magazines and solving puzzles and sudoku can also help to cure brain fog.

  • Developing social connections and interaction with people experiencing similar issues also plays an important role in dealing with brain fog related to COVID-19.

  • Long COVID often causes stress; therefore, people should opt for stress management techniques, such as meditative walking, yoga, breathing exercises, and guided imagery, and engage in their hobbies.

In addition, in severe cases of COVID-19 brain fog, a person may require cognitive rehabilitation that helps them regain their brain function to optimal levels. There are mainly two categories of cognitive rehabilitation:

  • People are trained to develop new thinking patterns and behaviors to deal with cognitive impairment.

  • New behaviors are reinforced in people that boost their cognitive function.

What Are the Other Medical Conditions That Can Cause Brain Fog?

  • Migraine.

  • Anemia.

  • Depression.

  • Sjogren syndrome.

  • Diabetes.

  • Anemia.

  • Hypothyroidism.

  • Alzheimer's disease.

  • Dehydration.

  • Autoimmune diseases, such as multiple sclerosis, arthritis, and lupus.


COVID-19 brain fog usually develops a few days to months after a person recovers from other symptoms of COVID-19. It is believed that brain fog develops due to physiological changes caused by COVID-19 in the brain and other psychological factors that further contribute to this brain condition. These neurological symptoms occur in a few people suffering from COVID-19. However, researchers are still finding out why brain fog is not common in all people who suffer from COVID-19. Therefore, any person experiencing cognitive impairment, brain fog, and altered thinking ability post-COVID-19 or long COVId should consult a doctor immediately and take regular follow-ups. Also, those with pre-existing neurological conditions should consult their doctor for regular follow-ups to properly manage the condition to prevent the symptoms from worsening.

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Dr. Arpit Varshney
Dr. Arpit Varshney

General Medicine


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