Chronic Fatigue Syndrome: Symptoms, Causes, & Treatment

By Craig Sorkin, DNP, APN
Medically reviewed checkmarkMedically reviewed
June 22, 2022

Chronic fatigue syndrome (CFS), also called myalgic encephalomyelitis (ME), causes overwhelming fatigue that is not improved by sleep or rest.

CFS is sometimes also called systemic exertion intolerance disease (SEID).

It’s estimated that  836,000 to 2.5 million Americans have this complex, chronic illness, though as many as 90% of them have not been diagnosed.

Some people with ME/CFS may outwardly appear to be in good health.

But that doesn’t mean they are not sick.

There is no specific test for diagnosing ME/CFS, but researchers have found many ways in which the bodies of people with ME/CFS function differently from their peers.

In this article, I’ll discuss what it’s like to have ME/CFS, as well as identify who is at risk for the disease.

I’ll outline the research about the causes of chronic fatigue syndrome, as well as its most common symptoms.

I’ll talk about how doctors and healthcare providers diagnose ME/CFS, and provide an overview of the most up-to-date treatment approaches, including medication, lifestyle changes, and alternative medicine.

I’ll discuss whether it’s possible to prevent ME/CFS, and the major complications that accompany the illness.

Finally, I’ll review what we know about the long-term outlook for people with ME/CFS, and when to talk to your doctor about this disease.

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What is Chronic Fatigue Syndrome?

Chronic fatigue syndrome is characterized by extreme fatigue that can’t be explained by a patient’s other underlying medical conditions.

This fatigue does not improve with rest.

And it can get worse after any physical or mental activity. 

More than 1 in 10 Americans say they regularly feel tired or exhausted.

People with ME/CFS, however, often experience fatigue in some of its most extreme, long-lasting, and hard-to-pinpoint forms.

Daily tasks that many of us take for granted, such as taking a shower or shopping for groceries, can leave people with ME/CFS with debilitating fatigue for days.

This reaction is called post-exertional malaise (PEM).

At least one in four ME/CFS patients are regularly house-bound or bed-bound for extended periods, and three in four become house-bound or bed-bound on their worst days.

For years, doctors thought of ME/CFS as an especially “invisible” or elusive illness to identify.

However, CFS is not an ailment that is “all in people’s heads.”

While there is still no one single test that can identify ME/CFS, researchers have begun to identify many key differences in the bodies of people with ME/CFS.

Research suggests that many people with ME/CFS have different patterns of metabolism and autoimmune response than non-sufferers.

(Chemicals called cytokines are an important part of this autoimmune response, and are known to cause inflammation—perhaps leading to increased fatigue.) 

ME/CFS sufferers also may display distinct imbalances in systems that manage serotonin, an important brain chemical, and antioxidants, substances that protect against inflammation.

ME/CFS patients also seem to suffer from circulatory problems that lead to lower levels of oxygen delivery and a depletion of energy nutrients.

The gut microbiome of people with ME/CFS is also markedly different from those without the disease, which could affect how the gut and brain systems interact.

For all of these examples, it is currently unclear if these differences are a cause or a consequence of ME/CFS.

But they are clear signs of the disease’s far reach throughout the body.

Who is at risk for chronic fatigue syndrome?

Chronic fatigue syndrome is most common in people between 40 and 60 years old, but it can occur in kids, teenagers, and adults of all ages. 

ME/CFS also affects all genders, though women are currently 2-4 times more likely to be diagnosed with ME/CFS.

ME/CFS also affects people across all racial, ethnic, and socioeconomic groups. 

Increasing evidence—including family history studies and genetic analysis—supports the idea that people with certain genes may be more vulnerable to developing chronic fatigue syndrome.

But the exact genetic mechanism remains unknown.


Much about the causes of chronic fatigue syndrome have yet to be understood.

Researchers are holding out the possibility that ME/CFS arises as the result of several interacting triggers, which may include:

  • Certain infections
  • Immune system changes
  • Mental traumas or stresses
  • Physical injuries or stresses
  • Immune system changes
  • Differences in metabolism and energy production
  • Genetic vulnerability

Some people with ME/CFS report that the illness began following a period of great physical stress, such as surgery.

Others say their illness started after a flu-like illness, cold, or stomach bug.

Research has shown around 10% of people who develop certain infections–such as Epstein-Barr virus, Q fever, and epidemic polyarthritis—are later diagnosed with ME/CFS.

Many of these infections affect the central nervous system.

None of these explanations currently encompass all people diagnosed with ME/CFS.

This is one reason researchers suspect it may be triggered by a variety of factors. 


There is no one set of symptoms that is shared by all sufferers of chronic fatigue syndrome.

Even with a single patient, symptoms may come and go.

Some of the most common ME/CFS symptoms include:

  • Severe fatigue that is not improved by rest 
  • Post-exertional malaise (PEM)
  • Pain
  • Dizziness
  • Problems with thinking, concentrating, and memory
  • Brain fog
  • Difficulty sleeping and unrefreshing sleep
  • Joint and muscle pain
  • Sore throat
  • Tender lymph nodes
  • Headaches

Less common symptoms of ME/CFS include:

  • Visual problems
  • Psychological instability
  • Chills and night sweats
  • Fever or low body temperature
  • Irritable bowel
  • New allergies and sensitivities
  • Numbness, tingling, or burning sensations in the extremities


ME/CFS cannot be diagnosed with a single test.

Instead, your doctor will need to perform a thorough physical and mental evaluation, and may order laboratory tests and specialist consultations, all in order to eliminate other conditions with similar symptoms.

While performing these evaluations, your doctor will check the results against a new definition of ME/CFS that was released in 2015.

Three “core” or primary symptoms are now needed for diagnosis:

  • A drop in activity level: Having a lowered ability to do activities that were usual before the illness. This drop in activity level occurs with fatigue, and must last six months or longer. This fatigue was not a problem before becoming ill (ie., not lifelong).
  • 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. People with ME/CFS may also have problems falling or staying asleep.

In addition, one of the following two symptoms is required for diagnosis:

  • Problems with thinking and memory: Having trouble thinking quickly, remembering things, and paying attention. People with ME/CFS may experience “brain fog” and feelings of “stuckness.”
  • Orthostatic intolerance: Worsening of symptoms while standing or sitting upright. People with ME/CFS may also become lightheaded or dizzy when fully upright.  


ME/CFS currently has no cure. Most treatments are focused on relieving symptoms.

These treatment approaches should only occur under your healthcare provider’s supervision.

Some treatments that are sold as cures for CFS are unproven and even dangerous, so always talk to your doctor before trying something new.

Lifestyle changes

Lifestyle changes to manage the symptoms of ME/CFS can be put in place at home and at work.

About half of all people with ME/CFS work a part-time or full-time job.

Many of these people can benefit from adjustments like more flexible schedules, rest areas, and memory aids on the job.

At home, “activity management” approaches can help you learn to pace your activities and avoid a “push hard and crash” cycle that leads to post-exertional malaise.

You can also work with a physical therapist to learn lower-impact ways of doing daily tasks, and with a mental health counselor to process the difficulties of living with ME/CFS.

Wearable tools like heart rate monitors and compression stockings (to potentially improve blood flow, and reduce orthostatic intolerance) may also prove helpful to some people.

More research needs to be done on the role of anti-inflammatory diets in managing ME/CFS symptoms.


Attempts to treat or cure ME/CFS directly with medication have not yet succeeded, or are still in early stages.

But  medication can be useful in managing symptoms for some people with ME/CFC:

  • Sleep: Some people might benefit from a sleep aid medication if they struggle with falling asleep (even if this won’t relieve chronic daytime fatigue).
  • Pain: Over-the-counter and prescription pain medications can help some people with joint and muscle pain.
  • Concentration: Stimulant medications used to treat disorders like Attention Deficit Hyperactivity Disorder (ADHD) may help some ME/CFS patients with concentration and memory problems. There is a risk, however, of these drugs contributing to “push-and-crash” cycles.

Alternative medicine

The main goal of alternative medicine is primarily to alleviate symptoms, rather than cure ME/CFS.

Approaches like meditation, yoga, and tai chi can reduce anxiety and promote feelings of well-being.

Acupuncture, massage, and water therapy may help with pain management. 

Research on natural supplements like magnesium, melatonin, vitamin B12, and coenzyme Q10 has not yet yielded clear evidence of these remedies’ effectiveness.


Most people who develop chronic fatigue syndrome were generally healthy and active prior to falling ill.

As the exact causes of ME/CFS are not yet known, there is currently no protocol on how to prevent its emergence.


Some people with chronic fatigue syndrome also experience depression, stress, and anxiety related to their diagnosis.

Although ME/CFS is not a psychological condition, the unpredictability and discomfort surrounding the disease can prove stressful and demoralizing.

People with ME/CFS may also be diagnosed with additional disease comorbidities.

They can include:

Long-Term Outlook

Some people with ME/CFS recover over time, even approaching a “full” recovery.

There is some evidence that children and young people with ME/CFS may have higher rates of recovery. 

Other people may grow progressively worse with time.

For many patients, ME/CFS will follow a cyclical course, with periods of more severe illness alternating with periods of more relative well-being.

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When to See a Medical Provider

One of the most important factors in managing ME/CFS, and maximizing quality of life, is building a strong relationship with an experienced medical provider.

This is a process that starts with getting a diagnosis—something many people with ME/CFS unfortunately never receive. 

Talk to your doctor if you begin to experience extended periods of severe fatigue that cannot be improved by rest.

Let your doctor know if you begin to experience memory and concentration problems, or start to have trouble holding your body upright.

If you already have an ME/CFS diagnosis, talk with your doctor before trying any new symptom management tools, medications, supplements, or alternative medicines.

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

How K Health Can Help

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Frequently Asked Questions

What does chronic fatigue feel like?
Chronic fatigue feels like a big change from how you used to move through the day. Simple tasks you used to do with ease can now leave you exhausted for days or weeks—and sleep no longer helps you feel less tired.
How long does chronic fatigue syndrome last?
It takes six months for a bout of severe fatigue to be considered chronic. From that, chronic fatigue syndrome can last for months or years, sometimes in cycles of flare-ups and remissions.

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.

K Health has strict sourcing guidelines and relies on peer-reviewed studies, academic research institutions, and medical associations. We avoid using tertiary references.

Craig Sorkin, DNP, APN

Craig Sorkin, DNP, APN is a board certified Family Nurse Practitioner with over 15 years experience. He received his Undergraduate and Graduate degrees from William Paterson University and his doctoral degree from Drexel University. He has spent his career working in the Emergency Room and Primary Care. The last 6 years of his career have been dedicated to the field of digital medicine. He has created departments geared towards this specialized practice as well as written blogs and a book about the topic.

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