Chronic Fatigue Syndrome


Written by Kimberly Solis

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Everyone feels tired from time to time. Exhaustion may set in from working long hours, taking care of small children, or fulfilling other obligations. This type of occasional fatigue is normal and usually gets better with rest. 

In contrast, significant, long-lasting fatigue can be an indication of a bigger problem. When persistent fatigue negatively affects daily life, has no known cause, and occurs with other symptoms, it may be a sign of chronic fatigue syndrome (CFS). 

Experts still haven’t found what causes CFS, but they know that its symptoms represent a real medical condition with profound impacts on the people who have it.

If you experience ongoing fatigue, it is important to talk with your doctor. Many other health problems and sleep disorders may cause you to feel tired, so consulting with a doctor is necessary to get help and to determine whether you have chronic fatigue syndrome. 

Learning about the symptoms, causes, diagnosis, and potential treatment of chronic fatigue syndrome can help you understand this condition and be prepared to discuss it with your doctor.

What is Chronic Fatigue Syndrome?

Chronic fatigue syndrome (CFS) is a disorder that causes extreme exhaustion over a time period of at least six months. Another name for CFS is myalgic encephalomyelitis, and the condition is sometimes called myalgic encephalomyelitis/chronic fatigue syndrome (ME-CFS).

Fatigue isn’t the only symptom of CFS. The condition can also cause problems like difficulty thinking, poor sleep, and body pain. That said, the core symptom is considerable fatigue that doesn’t get better with rest and can be extremely disruptive or even debilitating. 

The cause of CFS remains unknown, but researchers hypothesize that it could be linked to problems with the immune system, nervous system, or metabolic function. 

CFS is uncommon, and most people with fatigue do not have CFS. Short-term fatigue, even if severe, is distinct from chronic fatigue syndrome, which involves symptoms lasting for at least six months. Even among people with long-lasting fatigue, fewer than 10% actually have CFS.

Chronic Fatigue Syndrome Symptoms

The central symptom of chronic fatigue syndrome is exhaustion that may feel overwhelming. This fatigue continues for six months or longer and frequently ranges from moderate to severe in intensity. 

Chronic fatigue syndrome may develop without warning. It can arise abruptly after a stressful situation, but it can also emerge gradually over time. Fatigue often gets worse with activity, when standing up, or when stressed. This fatigue generally continues even after trying to rest. 

But exhaustion is not the only symptom of chronic fatigue syndrome. Other CFS symptoms include: 

  • Cognitive issues including struggling to concentrate, remember things, and think clearly 
  • Sleep problems such excessive daytime sleepiness or feeling like sleep is not refreshing 
  • Headaches and pain that may affect the joints, muscles, stomach, throat, lymph nodes, and chest 
  • Other physical problems like skin rash, dizziness, nausea, fever, quickened pulse, and weight changes 

Having CFS may affect mood and mental health. Ongoing fatigue can be frustrating and upsetting, especially if other people question whether a person’s symptoms are real. 

Symptoms can change over time. Certain symptoms may get better or even go away for a while, but they may also reappear or worsen without warning.

What Causes Chronic Fatigue Syndrome?

No one knows exactly what causes chronic fatigue syndrome. Doctors don’t agree on whether CFS is caused by a single issue or multiple factors. Some prevailing theories hold that CFS is related to improper function of the immune, nervous, or metabolic system. 

Some experts believe CFS could be tied to an infection because there are reports of CFS symptoms appearing after having a cold or flu or recovering from mononucleosis, which is caused by the Epstein-Barr virus. Other people have found CFS to begin after periods of significant stress, and some theories hold that CFS could be linked to allergies or other sensitivities.

Another view argues that the condition is tied to abnormalities in the body’s system for producing energy. Some experts also believe that CFS may be triggered by problems in the nervous system or immune system. 

CFS may also have a genetic component. While no single gene is believed to cause CFS, certain people may have a genetic predisposition to developing CFS if exposed to an environmental trigger.

Among experts, there is no consensus supporting any one of these theories, and further research is needed to identify the potential causes of CFS. 

Who’s At Risk for Chronic Fatigue Syndrome?

Because the cause of chronic fatigue syndrome is unknown, isolating risk factors can be challenging. Analysis of risk factors generally involves looking for patterns among people diagnosed with CFS. 

For example, most people who have CFS are young adults or middle aged. Less often, the condition may affect children or older adults. Women and people assigned female at birth are up to two times more likely to develop CFS. 

Data shows that people of certain racial or ethnic groups may be more likely to be diagnosed with CFS, but these correlations could relate to varying degrees of access to health care across different groups. 

Chronic Fatigue Syndrome Tests and Diagnosis

There is no test that can diagnose chronic fatigue syndrome. Instead, CFS is diagnosed based on the presence of certain symptoms and tests to rule out other causes of those symptoms. 

While CFS can cause a wide range of symptoms, the diagnosis of CFS requires the presence of three specific issues: 

  • Fatigue that interferes with everyday life, lasts at least six months, has no clear cause, and does not get better with rest
  • Worsening of fatigue with stress or with physical or mental exertion
  • Sleep that is not refreshing

In addition, to be diagnosed with CFS, a person must have at least one of two additional symptoms: 

  • Problems with thinking, memory, or attention
  • Symptoms that get worse when standing up and tend to get better why lying back down

In people with CFS, this collection of symptoms occurs on most days and ranges from moderate to severe. 

To determine if a person meets these criteria, a doctor usually starts with a physical exam and a review of a person’s symptoms and health history. Because CFS can only be diagnosed if there is no other identifiable cause of symptoms, a doctor may suggest tests to rule out other medical conditions such as:

  • Sleep disorders
  • Anemia
  • Thyroid disorders 
  • Adrenal gland disorders
  • Inflammatory conditions like rheumatoid arthritis
  • Kidney problems
  • Abnormal electrolyte levels

In most cases, this involves lab tests to check the levels of various substances in the blood. To rule out sleep disorders like obstructive sleep apnea, a doctor may order a sleep study.

Chronic Fatigue Syndrome Treatment

Unfortunately, there is no treatment to cure chronic fatigue syndrome. As a result, the goal of treatment is limited to trying to address symptoms. 

If you have been diagnosed with CFS, your doctor will tailor your treatment plan according to the symptoms that you find most difficult and disruptive. Various kinds of treatments may be suggested based on your specific situation. 


Medications may help manage symptoms of chronic fatigue syndrome. For example, medications may be prescribed to try to decrease pain, promote sleep, or reduce depression.


Regular physical activity may be beneficial if it does not cause significant pain or exacerbate other CFS symptoms. Your doctor or a physical therapist may help to identify an exercise and activity plan that suits your needs and abilities.

Cognitive Behavioral Therapy for CFS

Although it does not work for everyone, you may find that cognitive behavioral therapy (CBT) helps to treat your symptoms. CFS is not a mental health issue, but talking with a licensed counselor or psychotherapist may help you feel prepared and empowered in your attempts to feel better. Talking with a mental health professional may also help you adjust to living with fatigue and sleep problems. 

At the same time, the mental exertion required for CBT has the potential to worsen symptoms of chronic fatigue syndrome. For that reason, it is important to talk with your doctor and a therapist who can discuss the pros and cons of CBT and can initiate this treatment at a pace that works for you. 

Unproven Treatments for CFS

Some people try other kinds of CFS treatments, including some that are unproven and are not supported by doctors. Some of these treatments have the potential to cause serious side effects, so it is essential to consult with a doctor before trying them. These unproven treatments include: 

  • Exclusion diets, which restrict consumption of specific foods
  • Various supplements, vitamins, extracts, and essential oils
  • Steroids, antihistamines, antibiotics, and antiviral medications
  • Taking out dental fillings

Frequently Asked Questions About Chronic Fatigue Syndrome

Is chronic fatigue syndrome a real condition? 

Chronic fatigue is a real condition with real symptoms. CFS is officially recognized by prestigious organizations like the Institute of Medicine and the National Academy of Sciences. 

If you have CFS, it may be validating to know that your symptoms are real and worthy of attentive medical care.

If you know someone who has CFS, it is important to take their condition seriously. Downplaying or denying their symptoms can cause them additional frustration and stress. 

How common Is chronic fatigue syndrome? 

Chronic fatigue syndrome is a rare condition. Experts estimate that at most there are 2.5 million people in the United States with CFS, which means that the disease affects well under 1% of the population. 

Is all fatigue a sign of chronic fatigue syndrome? 

The vast majority of people with fatigue do not have chronic fatigue syndrome. 

If fatigue lasts for less than six months, it is not CFS. Furthermore, while it is estimated that up to 25% of people have long-term fatigue, fewer than 10% of those people are believed to have CFS. 

In most cases, fatigue is caused by another issue or does not occur with the other symptoms indicative of chronic fatigue syndrome. 

About The Author

Dr. Michael Breus

Clinical Psychologist, Sleep Medicine Expert

Michael Breus, Ph.D is a Diplomate of the American Board of Sleep Medicine and a Fellow of The American Academy of Sleep Medicine and one of only 168 psychologists to pass the Sleep Medical Specialty Board without going to medical school. He holds a BA in Psychology from Skidmore College, and PhD in Clinical Psychology from The University of Georgia. Dr. Breus has been in private practice as a sleep doctor for nearly 25 years. Dr. Breus is a sought after lecturer and his knowledge is shared daily in major national media worldwide including Today, Dr. Oz, Oprah, and for fourteen years as the sleep expert on WebMD. Dr. Breus is also the bestselling author of The Power of When, The Sleep Doctor’s Diet Plan, Good Night!, and Energize!

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