Post-Viral Fatigue and CFS: Symptoms, Causes, Diagnosis, and Treatment

Katie Rapkoch, CHPC

Published on

January 18, 2024

Updated on

January 18, 2024

Medically reviewed by

Ben Ahrens, HHP

For many people, contracting a virus results in a week or two of symptoms and downtime. Being “out of commission” with a viral infection is uncomfortable and frustrating, but kept in perspective, it’s really a minor inconvenience, as recovery generally comes relatively quickly. For other people, however, becoming ill with a virus can lead to months, years, or even a lifetime of debilitating symptoms that drastically reduce their quality of life.

These symptoms, referred to as post-viral fatigue syndrome, have been reported by sufferers of many viral illnesses, including Epstein-Barr virus, glandular fever, SARS, and now, COVID-19. One recent study[1] found that more than half of the study participants who had tested positive for COVID-19 were still experiencing persistent fatigue ten weeks after the initial infection.

Post-viral fatigue is related to chronic fatigue syndrome (CFS), both of which are thought to have an infectious trigger. The difference is that with ME/CFS, the trigger often goes unrecognized, meaning the affected person is not aware that they even had an infection.

In a 2009 research paper entitled Kindling and Oxidative Stress as Contributors to Myalgic Encephalomyelitis/Chronic Fatigue Syndrome[2], Dr Leonard Jason and his colleagues suggest that persistent hyperarousal of the central nervous system could lead to chronic sympathetic dominance which may trigger a cascade of inflammatory cytokines that leads to many of the symptoms and abnormalities reported by ME/CFS patients. In this article, we’ll be covering everything you need to know about post-viral fatigue, including how re-origin, a neuroplasticity-based treatment program, has helped others rid themselves of symptoms and get back to doing all of the things they love.

Generally speaking, Post-Viral Fatigue is also commonly referred to as:

  • Post-Viral Fatigue Syndrome(PVFS)
  • Post-Infectious Fatigue
  • Long-COVID
  • Chronic Post COVID-19 Syndrome (CPCS)
  • Chronic Fatigue Syndrome (CFS)

Symptoms of Post-Viral Fatigue

While the symptoms of post-viral fatigue or post-viral syndrome vary from person to person, the most common symptoms include[3]:

  • Severe fatigue despite getting adequate sleep
  • Sore throats
  • Headaches
  • Swollen lymph nodes
  • Muscle pain
  • Joint pain
  • Difficulty concentrating
  • Memory problems
  • Brain fog
  • Malaise
  • Post-exertional malaise (PEM) in response to heightened activity levels
  • Anxiety, depression, and other mental health issues

In some cases, post-viral fatigue can also manifest as fibromyalgia, food sensitivities, chemical sensitivities, electromagnetic field (EMF) sensitivities, arthritis, and feelings of anxiety, burnout, and depression. While these conditions might not seem related at first glance, new research suggests that the brain may play a central role in many, of what have come to be known as, self-perpetuating inflammatory conditions. If you have recently had a viral infection and are experiencing one or more of the above symptoms weeks, months, or years after originally becoming infected, you may be experiencing post-viral fatigue. Many post-viral fatigue sufferers express that they feel as though they have a constant low-level flu or that they just can’t seem to bounce back to full health.

For some people, the symptoms wax and wane. In others, the symptoms are more or less constant. Additionally, many sufferers notice that their symptoms can be made worse by stress of any kind, whether physical or psychological.

Causes and Risk Factors of Post-Viral Fatigue

Post-viral fatigue can occur when a person becomes infected with a virus while their chronic stress load is already high. Let’s say, for example, you contract COVID-19 when you’re going through a divorce. The new thinking as it pertains to these complex neuroimmune conditions is that the combination of stressors may essentially overwhelm the brain and temporarily change the circuitry in a part of the brain called the limbic system. The limbic system is not only involved in your behavioral and emotional responses, but it also drives your primal fight/flight/freeze response which can impact the function of the peripheral immune system. Based on findings from recent brain imaging studies, neuroscientists have theorized that when the limbic system is overactive in this way, its protective mechanisms can fire inappropriately and trigger an inflammatory reflex. At this point, bodily symptoms may be perceived as threats via the insular cortex and further trigger the limbic system to continuously send out alarm signals that stimulate the nervous system and immune system, even when there is no threat present. This over-responsiveness ultimately becomes learned through conditioning, meaning the person gets stuck in an unconscious loop that perpetuates itself. This continuous stimulation of the nervous system and the immune system is now becoming recognized as a possible enabling condition that may serve to perpetuate post-viral fatigue symptoms.

Post-viral fatigue can affect people of all ages, however, it’s important to note that not everyone who contracts a viral illness will develop post-viral fatigue. There are, however, some risk factors[4] that may make one more likely to develop post-viral fatigue after a viral illness. These include:

  • Having a high chronic stress load prior to contracting the virus
  • Having experienced trauma prior to contracting the virus
  • Experiencing a severe viral infection (although some people who experience a mild viral illness also develop post-viral fatigue)

How Post-Viral Fatigue is Diagnosed

Diagnosing post-viral fatigue is often difficult, as its symptoms overlap with many other health conditions, and is often done by process of elimination, often called a diagnosis of exclusion[5] in lieu of there being any positive diagnostic markers for PVF. A medical professional will begin the diagnostic process by assessing your symptoms, taking your medical history, and performing a physical exam. Blood tests will also be run to rule out common sources of fatigue, such as hypothyroidism or anemia.

Post-viral fatigue will likely be diagnosed if:

  • Other medical conditions are ruled out.
  • Your symptoms reflect those of post-viral fatigue.
  • Your symptoms appeared following a viral infection.
  • Your symptoms don’t abate within 6 to 8 weeks despite rest and self-care.
  • Other forms of chronic illness are ruled out.

How Post-Viral Fatigue is Treated

Because most medical professionals don’t yet fully understand the pathophysiology of post-viral fatigue, there aren’t any precise treatment protocols commonly offered through mainstream medicine. In traditional or mainstream medicine, treatment generally focuses on managing symptoms while alternative medicine tends to focus on reducing an individual’s viral load and reducing inflammation. At the current moment, the scientific understanding of brain-body interrelationships in the diagnosis and treatment of PVF is in its infancy and is considered controversial among mainstream health scientists. For this reason, it is reasonable to expect some medical providers to be skeptical of PVF as a working diagnosis.

Before we delve into how to address post-viral fatigue from a neurological perspective, let’s discuss common traditional and alternative treatment options and the advantages and disadvantages of each approach.

Reducing daily activities to conserve energy

The most commonly suggested treatment is rest. This means relaxing or sleeping when you feel tired (which may be all the time), getting at least 8 to 9 hours of sleep a night, and reducing daily activities. This method is aimed at conserving energy and giving the body the downtime it needs to recover.

While it might seem that rest is helping at the moment, it doesn’t ultimately address the root cause of the condition. Additionally, solely relying on getting excessive rest to function can significantly hinder every aspect of your life, from productivity to relationships to your sense of well-being.

Pain medication

Taking pain medication can help ease the muscle and joint pain that often comes with post-viral fatigue. Managing pain can help improve the quantity and quality of your sleep at night, which may help reduce fatigue during the day. Taking pain medication may provide temporary relief, but it does nothing to address the root cause of post-viral fatigue.

Relaxation techniques

Some people report feeling more rested after practicing relaxation techniques, such as yoga, deep breathing, or meditation, or receiving a relaxing treatment, such as acupuncture, massage, or reiki. These therapies may provide temporary relief and help calm an overactive stress response to a certain degree, however, they fail to address the conditioned pathways in the brain that contribute to the persistent sympathetic arousal that is so prevalent when it comes to perpetuating the symptoms of post-viral fatigue.

Diet & detoxification

Some medical practitioners, especially naturopaths, functional medicine doctors, and integrative medicine doctors, will suggest a certain diet or detoxification protocol aimed at lowering a patient’s viral load. This treatment method is based on the theory that a latent virus is the cause of the post-viral fatigue symptoms.

Individuals may see some improvement in their symptoms through detoxification, likely due to a reduction in inflammation, however, most people aren’t able to fully resolve their symptoms via this route. This is because a latent virus isn’t likely the root cause of the symptoms. A latent virus may be contributing to symptoms to a certain degree, but it’s only able to do so because of a weakened immune system associated with the hyperarousal of the limbic system. Once the immune system returns to full strength, it is better equipped to keep the virus at bay.

How We Approach Post-Viral Fatigue

At re-origin, we believe that Post-Viral Fatigue Syndrome is the result of Classical (Pavlovian[6]) Conditioning whereby the limbic system may have effectively “learned” to over-protect the body by mounting a strong immune response during the time of acute infection. Then, later on, after the infection has subsided, the inflammatory cytokine activity remains elevated due to this past conditioning. – We also believe that by a similar process to how the limbic system can become conditioned or sensitized in the first place, it can also be deconditioned and desensitized through the deliberate use of self-directed neuroplasticity: Interrupting the previously conditioned neural pathways in the brain and calming the overactive threat-response system are the keys to reducing systemic inflammation and allowing the body to make a full recovery.

What the research says

There is now research[7] to support the notion that post-viral fatigue occurs when the limbic system becomes traumatized due to contracting a virus while your stress load is already high[8] . As it is understood, this combination overwhelms the brain, leading to an overactive stress response and unproductive, conditioned patterns in the brain. When in this impaired state, the limbic system inappropriately stimulates the immune system[9] and nervous system as if a viral threat was present, even though the original viral threat has long passed. The continuous stimulation of the immune system and nervous system are what leads to the symptoms associated with post-viral fatigue. This etiology is analogous to the development of chronic pain syndromes, where pain sensation centers in the brain persist even after the original injury causing the pain has resolved.

The good news is that these symptoms are temporary, and mounting anecdotal evidence suggests that many, if not all of these symptoms, can be attenuated thanks to neuroplasticity—the brain’s ability to change and develop new neural pathways. Using specific neurocognitive exercises, it is possible to get your brain and body out of “emergency mode” and back to a place of safety and balance where well-being can naturally resume.

re-origin’s approach is self-directed, meaning you can implement it entirely on your own. Additionally, this treatment does not chase or mask symptoms but rather works to rewire the part of the brain that is causing the dysfunction (the limbic system), resulting in long-lasting recovery. The program is easy to follow, cost-effective and takes just minutes a day to implement.

call to action banner

How to Live and Cope with Post-Viral Fatigue

There are many suggestions out there for living and coping with post-viral fatigue, some of which include resting, joining a support group, and practicing relaxation techniques. While all of these things are good practices and could offer some short-term benefits, they don’t get to the root of your post-viral fatigue symptoms.

At re-origin, we believe that nobody should have to live or cope with post-viral fatigue. We want you to recover, eliminating the need for coping mechanisms altogether. Our program involves applying an easy-to-follow, five-step neurocognitive technique to override and rewire faulty conditioning in the brain and create new, functional neural pathways. The key to overcoming post-viral fatigue lies in systematically applying our techniques and being persistent in your efforts. With dedication and repetition, you can change your brain and thus, its physiological impact on your body. You don’t have to live with post-viral fatigue and we are excited to help you reclaim your life.

A Final Word from re-origin

It can be very difficult to continue feeling fatigued and unwell after a viral illness, especially when you had expected to make a quick recovery and return to normal life. It’s important to understand, however, that the development of this condition was not your fault. Recent findings suggest that post-viral fatigue may result from the conditioning that causes the limbic system to maladapt[11]. Even more important to understand is that this condition is not permanent. Numerous neuroplasticity studies lend strong support to peoples’ ability to undo this faulty conditioning and make a full recovery with the help of neuroplasticity programs like re-origin.

The symptoms you’re experiencing are being perpetuated by a feedback loop in the brain. re-origin’s team of neuroscientists and psychologists have extensively studied this loop and how to break it, and have packaged that information into an easy-to-apply program that can help you reclaim your life. With our proprietary neuroplasticity training program, you can learn to undo the underlying cause of your condition, putting an end to the symptoms you’re experiencing once and for all.

No one should have to live with post-viral fatigue—and thankfully, you don’t have to! Recover your health, regain your peace of mind, and get back to doing all of the things you love with re-origin.


What is persistent fatigue?
add icon

When a person has persistent fatigue, they experience tiredness for weeks, months, or years that is constant and limiting and doesn’t improve with rest and adequate sleep. Persistent fatigue symptoms can overlap with any other causes of fatigue including depression, anxiety, insomnia or transient fluctuations in health and wellbeing.

What does persistent fatigue mean?
add icon

Simply put, persistent fatigue is characterized by extreme fatigue or tiredness that doesn’t go away.

Characteristics of persistent fatigue may include not feeling rested upon awakening in the morning, difficulties with memory, focus, and concentration, and dizziness that worsens when going from lying down to sitting or standing.

What can cause persistent fatigue?
add icon

There are several potential causes of persistent fatigue, so it’s important to schedule an appointment with your doctor to rule out any health conditions that need attention. Some common causes[10] of persistent fatigue include:

  • Anemia
  • Depression
  • Liver disease
  • Heart disease
  • Lung disease (COPD)
  • A bacterial or viral infection
  • Allergies/hay fever
  • Overtraining

Persistent fatigue symptoms can overlap with any other causes of fatigue including depression, anxiety, insomnia or transient fluctuations in health and wellbeing. Symptoms are often dismissed as “merely psychiatric” in nature. This is an unfortunate oversight among well-meaning health providers who are uncomfortable with diagnoses of exclusion like PVF.


Katie Rapkoch, CHPC