Everything You Need To Know About Fatigue After COVID-19

By Jennifer Nadel, MD
Medically reviewed checkmarkMedically reviewed
May 25, 2022

For some patients, the health effects of COVID-19 did not end when they passed through the initial, most acute, stage of their viral infection.

Doctors now recognize that some patients can experience lingering fatigue from their bouts with COVID-19, even if their original experiences with the disease were mild or moderate.

Some patients are reporting symptoms that last for weeks and months.

These patients are known as “long-haulers,” and are said to be experiencing “long COVID.”

One of the most common long-term symptoms reported by patients is fatigue, with up to 46% of all COVID-19 patients reporting fatigue that lasts from weeks to months.

This post-COVID-19 fatigue can lead to significant declines in quality of life, especially when experienced alongside symptoms like “brain fog” and sleep disorders.

While these symptoms may not be associated with an actively contagious case of COVID-19, they are still a major medical concern.

They should fall under a doctor’s care for proper supervision and treatment. 

In this article, I’ll talk about the science behind fatigue, and I’ll examine what we know today about the causes of post-COVID-19 fatigue.

I’ll review the major symptoms of post-COVID-19 fatigue, including how to tell when cases of post-COVID-19 fatigue begin to overlap with elements of chronic fatigue syndrome. 

I’ll also summarize what we know about how long post-COVID-19 fatigue can last.

I’ll discuss how to manage this fatigue, and when to see a doctor if you think you’re experiencing post-COVID-19 fatigue. 

What is Fatigue?

Fatigue can encompass everything from muscle weakness to drowsiness.

Most commonly, however, the term “fatigue” is used to describe feelings of low energy, heaviness, tiredness, and fogginess that affect the mind and body.

Fatigue can reduce our ability to work effectively, manage day-to-day routines, and maintain family and social relationships.

Extreme fatigue can cause us to be more prone to irritability and mood swings.

And it’s very common: The Centers for Disease Control and Prevention (CDC) reports that about 15.3% of women and 10.1% of men regularly feel very tired or exhausted.

This kind of fatigue can usually be addressed by getting more sleep and ensuring the body receives adequate rest.

Fatigue that arises as a result of illness is different. 

Fatigue brought on by illness can be understood as a way for the body to preserve energy while fighting off disease.

It may occur alongside symptoms like fever, muscle aches, and appetite change that are associated with an immune system response. 

When fatigue persists for 6 months or more, it is called “chronic.”

Chronic fatigue can be a symptom of an associated chronic illness, such as cancer or an autoimmune disorder.

But when doctors cannot pinpoint an obvious cause for a patient’s chronic fatigue, they will investigate whether it meets the criteria for a complex, multifaceted illness called myalgic encephalomyelitis, or chronic fatigue syndrome (ME/CFS).

More than a million Americans are estimated to have ME/CFS. 

Causes of Post-COVID-19 Fatigue

Post-COVID-19 fatigue is caused by the lingering effects of COVID-19 on patients’ minds and bodies.

What remains to be understood is exactly how and why this lingering effect occurs.

In cases where hospitalizations for severe cases of COVID-19 led to significant injury or lung damage, the reason for lingering fatigue is less of a mystery.

More puzzling are the cases of ongoing post-COVID-19 fatigue that occur in patients whose initial cases of COVID-19 were more moderate.

In some patients, the acute stage of COVID-19 passed relatively quickly without hospitalization, but the after-effects have lasted weeks or months. 

At this point, the syndrome known as long COVID still lacks a fully developed definition, set of symptoms, and treatment standards.

A significant minority of COVID-19 patients are continuing to experience ongoing effects, while others recover more fully.

Researchers are now investigating whether long COVID has multiple triggers, which might explain why some COVID-19 patients develop lingering post-COVID-19 fatigue and others don’t.

Early research suggests genetics may help determine who develops long COVID.

The presence of certain physical or mental traumas at the time of contracting COVID-19 might also serve as triggers.

On a cellular level, post-COVID-19 fatigue itself may act on the body as a series of overlapping disorders.

It’s likely, for instance, that in some patients, acute COVID-19 can damage the body’s ability to circulate oxygen from the lungs.

This might contribute to long COVID patients becoming exhausted when performing tasks that once gave them no trouble.

Other research has focused on disordered immune responses in the long COVID population.

In some long COVID patients, the body’s immune system may continue to vigorously hunt down and destroy any remaining genetic traces it can find of the virus.

As the body deploys special tools to destroy these remnants, the body’s own cells may become attacked or inflamed. This may, in turn, cause fatigue. 

Symptoms of Post-COVID-19 Fatigue

Post-COVID-19 fatigue is a condition characterized by ongoing, significant fatigue and forgetfulness in patients who have previously recovered from COVID-19.

The chief symptoms include:

  • Tiredness
  • Brain fog
  • Memory impairment
  • Cognitive dysfunction
  • Headaches
  • Insomnia
  • Loss of joy 
  • No longer feeling like yourself
  • Post-exertional malaise

(Post exertional-malaise occurs when you feel exhausted and unwell after performing tasks that had once been easy. For example, you might need to rest after taking a shower.)

If it lasts six months, long COVID patients’ fatigue is officially chronic in nature.

Because post-COVID-19 fatigue is such a new phenomenon in medical literature, doctors may opt to assess the symptoms of patients with chronic post-COVID-19 fatigue against the more established diagnostic benchmarks of chronic fatigue syndrome.

They are: 

  • A drop in activity level: Having a lowered ability to do activities that were usual before the illness.
  • Post-exertional malaise: Experiencing debilitating fatigue after performing a physical or mental activity that would not have caused a problem before illness. It may take days or even weeks to recover from this “crash.”
  • Sleep problems: Experiencing fatigue that is not alleviated by sleep or rest.

In addition, one of the following two symptoms is also required for diagnosis of chronic fatigue syndrome:

  • Problems with thinking and memory: Having trouble thinking quickly, remembering things, and paying attention.
  • Orthostatic intolerance: Worsening of symptoms, and becoming lightheaded or dizzy, while standing or sitting upright.

Today, some chronic post-COVID-19 fatigue patients meet all of these criteria.

This has led many doctors to argue that their patients with “COVID-induced post infective fatigue syndrome” (PIFS) deserve the same government support and disability accommodations as more traditional ME/CFS patients.

How Long Can Post-COVID-19 Fatigue Last?

Researchers are still gathering data on the typical course of post-COVID-19 fatigue.

Surveys and patient reports have shown that a significant minority of COVID patients experience feelings of fatigue for more than six months.

For other COVID-19 patients, post-COVID-19 fatigue lasts for shorter periods of days or weeks.

And for some patients, these fatigue symptoms never appear.

Just as it’s possible that there’s no one universal trigger for post-COVID-19 fatigue, it is likely that the duration of this fatigue will depend on a variety of individual and environmental factors.  

How to Manage Post-COVID-19 Fatigue

At the moment, there is no cure for post-COVID-19 fatigue.

While some people with post-COVID-19 conditions have said that their symptoms improved after being vaccinated, more research is needed to determine how vaccination impacts post-COVID-19 conditions. 

Medical support for patients with post-COVID-19 fatigue is focused on relieving symptoms and maximizing quality of life.

If you have post-COVID-19 fatigue, there are “activity management” strategies you can learn to help you listen to your body and optimize your day based on your changing fatigue levels.

The goal is to conserve your energy levels as much as possible—thus lessening the chance of pushing too hard and crashing (also known as the PEM response).

If patients’ energy levels allow, certain kinds of low-impact movement routines—like tai chi or aqua therapy—may also promote positivity and well-being.

Physical therapists can help patients revise their daily routines to minimize unnecessary exertion.

And mental health professionals can help people process feelings of sadness and discouragement.

Doctors can also help patients address symptoms like body pain, headaches, attention deficit, depression and difficulties falling asleep.

Some chronic fatigue patients may be able to tolerate antidepressants, stimulants, or painkillers as part of their management plans.

Many others may not, and must instead rely more on lifestyle interventions for symptom management.

When to See a Doctor

If you currently have COVID-19, seek emergency medical care if you experience severe symptoms like difficulty breathing, persistent chest pain, abnormal confusion, and a difficulty staying away.

If you’ve recovered from acute COVID-19, contact a doctor if you are experiencing unusual levels of fatigue that haven’t gone away after several weeks or months.

Your doctor will especially want to know if you start to become exhausted or “crash” after performing once-simple tasks, or if your fatigue doesn’t seem to get any better with sleep.

If you and your doctor have already identified that you’re experiencing persistent post-COVID-19 fatigue, talk with your doctor before making any changes to your health plan.

This includes new symptom management tools, medications, supplements, or alternative medicines.

Some supposed “cures” can do more harm than good, or may conflict with an existing course of treatment. 

How K Health Can Help

Did you know you can access online urgent care with K Health?

Check your symptoms, explore conditions and treatments, and if needed, text with a healthcare provider in minutes. 

K Health’s AI-powered app is based on 20 years of clinical data.

Frequently Asked Questions

How long can fatigue last after COVID-19 infection?
Fatigue can last for weeks or months after a COVID-19 infection.
Can COVID-19 lead to chronic fatigue?
Yes, COVID-19 can lead to chronic fatigue in some people who experience post-COVID-19 fatigue for six months or more.

K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Jennifer Nadel, MD

Dr. Jennifer Nadel is a board certified emergency medicine physician and received her medical degree from the George Washington University School of Medicine. She has worked in varied practice environments, including academic urban level-one trauma centers, community hospital emergency departments, skilled nursing facilities, telemedicine, EMS medical control, and flight medicine.