Long Haulers, Brain Fog and Post Exertional Malaise

An excellent article recently published in the Atlantic was so well written that I have cut and pasted important snippets to help create this post. The review confirms many findings uncovered in my reading of several scientific publications.

You can read the full article here:

The crushing fog of long COVID

20 to 30 percent of patients report brain fog three months after their initial infection, as do 65 to 85 percent of the long-haulers who stay sick for much longer.

Of long COVID’s many possible symptoms, brain fog “is by far one of the most disabling and destructive,”

It is more profound than the clouded thinking that accompanies hangovers, stress, or fatigue.

It is not a mood disorder.

It is almost always a disorder of “executive function”—the set of mental abilities that includes:

  1. focusing attention,
  2. holding information in mind, and
  3. blocking out distractions.

Patients state they often lose focus mid-sentence.

Difficulty with simple tasks impairs activities of daily living.

“I couldn’t unload a dishwasher, because identifying an object, remembering where it should go, and putting it there was too complicated.”

The memories are there, but with impaired executive function, the brain neither chooses the important things to store nor retrieves that information efficiently.

Most people with brain fog are not so severely affected, and gradually improve with time. But even when people recover enough to work, they can struggle with minds that are less nimble than before.

“I’ve had surgeons who can’t go back to surgery, because they need their executive function,” Monica Verduzco-Gutierrez, a rehabilitation specialist at UT Health San Antonio.

That specific constellation of problems also befalls many people living with HIV, epileptics after seizures, cancer patients experiencing so-called chemo brain, and people with several complex chronic illnesses such as fibromyalgia.

It’s part of the diagnostic criteria for myalgic encephalomyelitis, also known as chronic fatigue syndrome, or ME/CFS

People with brain fog also excel at hiding it: to protect their jobs when still able to work, or to protect their reputation, or out of embarrassment.

“I know my value in many people’s eyes will be diminished by knowing that I have these cognitive challenges.”

Individuals with previously above average cognitive ability often test “normal” but suffer significant loss compared to their prior ability.

A team of British researchers analyzed data from the UK Biobank study. The findings revealed structural changes in the brain with loss of tissue on MRI scans that correlates with symptoms.

They found that even mild infections can slightly shrink the brain and reduce the thickness of its neuron-rich gray matter. At their worst, these changes were comparable to a decade of aging.

They were especially pronounced in areas such as the parahippocampal gyrus, which is important for encoding and retrieving memories, and the orbitofrontal cortex, which is important for executive function.

In most cases the virus probably harms the brain without directly infecting it.

Inflammatory chemicals can travel from the lungs to the brain, where they disrupt cells called microglia (immune cells in the brain).

In their presence, the hippocampusa region crucial for memoryproduces fewer fresh neurons, while many existing neurons lose their insulating coats (demyelination), so electric signals now course along these cells more slowly.

These are the same changes seen in cancer patients with “chemo fog”.

Neuro-inflammation is “probably the most common way” that COVID results in brain fog, but that there are likely many such routes, such as reactivation of dormant viruses such as Epstein-Barr virus, which has been linked to conditions including ME/CFS and multiple sclerosis.

By damaging blood vessels and filling them with small clots, COVID also throttles the brain’s blood supply, depriving this most energetically demanding of organs of oxygen and fuel.

These problems can be exacerbated or mitigated by factors such as sleep and rest, which explains why many people with brain fog have good days and bad days.

Although other respiratory viruses can wreak inflammatory havoc on the brain, SARS-CoV-2 does so more potently than influenza.

For adults following SARS CoV-2 infection:

risks of cognitive deficit (known as brain fog), dementia, psychotic disorders, and epilepsy or seizures were still increased at the end of the 2-year follow-up period.

For children following SARS CoV-2 infection:

in the 6 months after SARS-CoV-2 infection, children were not at an increased risk of mood (HR 1·02 [95% CI 0·94–1·10) or anxiety (1·00 [0·94–1·06]) disorders, but did have an increased risk of cognitive deficit, insomnia, intracranial haemorrhage, ischaemic stroke, nerve, nerve root, and plexus disorders, psychotic disorders, and epilepsy or seizures (HRs ranging from 1·20 [1·09–1·33] to 2·16 [1·46–3·19])….  Unlike adults, cognitive deficit in children had a finite risk horizon (75 days) and a finite time to equal incidence (491 days).

The fact that neurological and psychiatric outcomes were similar during the delta and omicron waves indicates that the burden on the health-care system might continue even with variants that are less severe in other respects.

There are no proven drug treatments for long-haulers.

But there is hope.

Cancer researchers have developed drugs that can calm inflamed microglia in mice and restore their cognitive abilities;

“Metformin can promote the regeneration of neural precursor cell populations and improve cognitive function in a preclinical model of cranial radiation and a pilot clinical study of children after cranial radiation and chemotherapy.”

Treating cancer therapy–related cognitive impairment | Nature Medicine

With regard to long-haulers, better sleep, healthy eating, and other generic lifestyle changes can make the condition more tolerable. Breathing and relaxation techniques can help people through bad flare-ups; speech therapy can help those with problems finding words.

“Some people spontaneously recover back to baseline,”

The largest group of long-haulers—those whose brain fog has improved but not vanished, can “maintain a relatively normal life, but only after making serious accommodations,”

Patients struggle to make peace with how much they’ve changed and the stigma associated with it, regardless of where they end up.

Post-exertional malaise—severe crashes in which all symptoms worsen after even minor physical or mental exertion is commonly reported.

Many long-haulers try to push themselves back to work and instead “push themselves into a crash,”

Post-exertional malaise is so common among long-haulers that “exercise as a treatment is inappropriate for people with long COVID,”

Even brain-training games—which have questionable value but are often mentioned as potential treatments for brain fog—must be very carefully rationed because mental exertion is physical exertion.

People with ME/CFS learned this lesson the hard way, and fought hard to get exercise therapy, once commonly prescribed for the condition, to be removed from official guidance in the U.S. and U.K.

In summary:

  1. Brain fog can occur even after mild or asymptomatic Covid-19.
  2. Although many patients improve over time, many are left with disability that can range from mild to incapacitating.
  3. Although these symptoms can occur following any viral infection, SARS CoV-2 seems to produce this with greater frequency compared to other viruses.
  4. Chronic brain inflammation is the likely cause in many individuals.
  5. Reactivation of Epstein Barr and/or other dormant viruses is suggested by various immune markers.
  6. The immune signature also suggests an immune response that mimics persistent infection in the absence of live SARS CoV-2 virus.
  7. Post exertional malaise following physical or mental exercise is a common and debilitating symptom without proven treatments. However there are guidelines that may help mitigate this devastating condition.
  8. Brain fog and post-exertional malaise are hallmarks of chronic fatigue syndrome/Myalgic encephalomyelitis which can occur following viral infections and major stress events such as physical and psychological trauma.
  9. Although not discussed in this post, chronically suppressed cortisol levels have been identified in this population. This in combination with physical changes noted on brain MRI demonstrate that there are physical correlates of brain fog.

In the meantime, preventive measures represent the low hanging fruit for health in general and with respect to the pandemic.

In the context of the COVID 19 pandemic I will close with the usual summary.

  1. Avoid alcohol consumption (alcohol wreaks havoc with your immunity)
  2. Get plenty of sleep (without adequate sleep your immune system does not work well )
  3. Follow good sleep habits
  4. Exercise, especially out of doors in a green space, supports the immune system
  5. Get some sunshine and make sure you have adequate Vitamin D levels. Supplement with Vitamin D3 to get your levels above 30 ng/ml, >40ng/ml arguably better.
  6. Eat an anti-inflammatory diet rich in micronutrients.
  7. Practice stress reduction like meditation and yoga which improves the immune system
  8. Eliminate sugar-added foods and beverages from your diet. These increase inflammation, cause metabolic dysfunction, and suppress immunity.
  9. Eliminate refined-inflammatory “vegetable oils” from your diet, instead eat healthy fat.
  10. Clean up your home environment and minimize your family’s exposure to environmental toxins by following recommendations at EWG.org with regards to household products, personal care products, and organic foods. (https://www.ewg.org/)
  11. Drink water filtered through a high quality system that eliminates most environmental toxins.
  12. If you are eligible for vaccination, consider protecting yourself and your neighbor with a few jabs. Age > 50 and/or risk factors means clear benefit from a booster.


Eat clean, drink filtered water, love, laugh, exercise outdoors in a greenspace, get some morning sunlight, block the blue light before bed, engage in meaningful work, find a sense of purpose, spend time with those you love, AND sleep well tonight.

Doctor Bob

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s