A Guide to Chronic Fatigue Syndrome

Medically Reviewed By Alana Biggers, M.D., MPH
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Chronic fatigue syndrome (CFS), also known as myalgic encephalomyelitis (ME), is a complex medical condition that affects many body systems and produces long lasting tiredness, achiness, and a general lack of energy. The cause of CFS/ME is not known. Many scientific studies have linked CFS/ME to viral infections, such as infections with the Epstein-Barr virus, but a definitive association has not been established.

Currently, there is no cure for CFS/ME. Treatments for CFS/ME aim to improve symptoms.

This article provides an overview of CFS/ME, including symptoms, causes, and treatment options for the condition.

What is chronic fatigue syndrome?

CFS/ME is a serious, long-term, debilitating disease. The disease causes profound fatigue. Getting rest does not help with the fatigue. This disease can affect many areas of the body, including muscles, joints, the head, the gastrointestinal system, and cognitive function.

People with CFS/ME have difficulty performing daily activities, and symptoms can worsen with activity. The disease can become chronic and lead to disability.

CFS/ME affects females more often than males. It is more common in adults 40-60 years old. It is rare, but possible, in children.

According to the Centers for Disease Control and Prevention (CDC), the Institute of Medicine (IOM) estimates that between 836,000 and 2.5 million people in the United States have CFS/ME.

Seek medical care if you experience severe fatigue that is new for you. This is especially true when fatigue does not go away with rest, seems to have no obvious cause, and interferes with your daily activities. 

What are the symptoms of chronic fatigue syndrome?

CFS/ME symptoms tend to be daily and ongoing, and they must have lasted 6 months or longer for a doctor to diagnose CFS/ME. In addition, you must have at least four other symptoms (besides fatigue) to be diagnosed with CFS/ME.

Most common symptoms

The most common symptoms of CFS/ME are:

  • severe fatigue that interferes with your daily activities
  • fatigue that gets worse after either physical or mental activities, called post-exertional malaise (PEM)
  • fatigue that is not relieved by rest or a solid night’s sleep
  • cognitive problems, such as remembering things or paying attention, sometimes called “brain fog”

Other symptoms

Other symptoms may include:

  • achy muscles or muscle weakness
  • joint pain without swelling or redness
  • headaches
  • lymph node tenderness, especially in the neck or armpits
  • frequent sore throat
  • fatigue that lasts more than 24 hours after light to moderate exercise
  • difficulty sleeping
  • digestive problems, including food sensitivities
  • lightheadedness when standing or sitting

What causes chronic fatigue syndrome?

No one knows for sure what causes CFS/ME, but research is ongoing. Scientists have some theories about what causes it, including infections, immune problems, or genetics.


Certain theories suggest that the condition may be caused by a virus or bacterial infection. About 10% of people with CFS/ME previously contracted one of the following illnesses:

Other possible causes of chronic fatigue syndrome

What are the diet and nutrition tips for chronic fatigue syndrome? 

Studies into how nutrition affects symptoms of CFS/ME are limited and offer mixed results.

However, eating a well-balanced diet can support overall health. This includes a variety of fruits and vegetables and healthy proteins.

Some people have “trigger foods” that make symptoms worse, so keeping a food journal may help you pinpoint your triggers. Limiting sugar, processed foods, additives, caffeine, and alcohol is also part of an overall healthy diet. 

How do doctors diagnose chronic fatigue syndrome?

There are no laboratory, blood, or imaging tests that can confirm a diagnosis of CFS/ME. Because many different medical conditions cause fatigue, doctors must rule out other plausible causes of symptoms before diagnosing CFS/ME.

To diagnose CFS/ME, your doctor will:

  • conduct a physical examination
  • ask you about your family history and personal medical history
  • ask questions about your current health and symptoms
  • order medical tests, which may include blood tests, urine tests, and imaging scans such as X-rays or MRIs to rule out other health conditions

Your doctor may also refer you to other specialists, who can check for conditions such as sleep apnea or arthritis.

Your doctor may diagnose you with CFS/ME if you have extreme fatigue and other symptoms of CFS/ME for at least 6 months and you have not been diagnosed with another condition that would explain your symptoms.

It may take 6 months or longer to diagnose CFS/ME. 

How is chronic fatigue syndrome treated? 

Currently, there is no cure for CFS/ME, but its symptoms are treatable with medications and other therapies. However, there are no drug treatments specifically for CFS/ME. 

Clinical treatments

Clinical or rehabilitation treatments provide therapies that can effectively treat some symptoms of CFS/ME. These therapies include:

  • cognitive-behavioral therapy
  • graded exercise programs
  • sleep clinic participation for sleep management techniques
  • energy management

Pain relief agents

You and your doctor should plan together which pain relief agents are most appropriate for your current pain levels. Nonsteroidal anti-inflammatory drugs (NSAIDs) are usually the first choice for pain control, and opiates are usually the last resort.

Pain relief agents used in CFS/ME include:

  • NSAIDs, such as ibuprofen (Advil, Motrin) or celecoxib (Celebrex)
  • local anesthetics such as lidocaine transdermal patches (Lidoderm)
  • the muscle relaxant tizanidine (Zanaflex)
  • the antimalarial agent hydroxychloroquine (Plaquenil) to help raise pain thresholds
  • antiepileptics, such as gabapentin (Neurontin), lamotrigine (Lamictal), oxcarbazepine (Trileptal), and topiramate (Topamax)
  • opiate narcotic analgesics or opiate agonists, which change the way the body senses pain, such as tramadol (Rybix, Ryzolt, Ultram), methadone (Dolophine, Methadose), or morphine (MS Contin)

Sleep aids/tricyclic antidepressants

Tricyclic antidepressant agents can be effective for both sleep disturbance and depression. They are effective sleep aids at much lower doses than are needed for depression. The most used drug in this class for CFS/ME is duloxetine (Cymbalta).

Complementary treatments

Complementary treatments that help some people with CFS/ME include:

  • acupuncture
  • massage therapy
  • nutritional dietary supplements, herbal remedies, tea beverages, and similar products
  • yoga

Be sure to notify your doctor before taking nutritional supplements or homeopathic (nonprescription) remedies, as they may interact with your prescribed medication.

How does chronic fatigue syndrome affect quality of life? 

People with CFS/ME often become exhausted after minor exertion. Basic daily activities may become extremely difficult. CFS/ME can make it difficult to go to school, to work, and to care for yourself or others.

According to the CDC, about 1 in 4 people with CFS/ME may need to stay in their bed or house

One of the challenges of living with CFS/ME is that symptoms can fluctuate. You may feel more fatigue and pain on some days than others. It can be difficult to predict when you will feel worse and when you will feel better. 

To help improve your quality of life:

  • Spread physically or mentally challenging tasks throughout the week or month.
  • Find ways to balance activity and rest.
  • Get enough sleep.
  • Maintain a healthy diet.
  • Divide big tasks into small, manageable steps.

What are the potential complications of chronic fatigue syndrome?

Complications of untreated or poorly controlled CFS/ME are not life threatening, but they can be debilitating. You can help minimize your risk of serious complications by following the treatment plan you and your doctor design specifically for you. CFS/ME complications may include:

  • depression from the effects of the disease
  • medication side effects
  • isolation due to inability to work, attend school, or participate in social activities

How chronic fatigue syndrome affects life expectancy

Researchers do not yet understand how CFS/ME affects life expectancy. 

The long-term outlook for people with CFS/ME varies. Some people completely recover, especially if they get treatment. However, others never feel like they did before they developed CFS/ME symptoms. Younger people have a better chance of full recovery.


Although CFS/ME is a poorly understood condition, its symptoms are often manageable with a variety of treatment options. Many people take a long time to get diagnosed with CFS/ME, which delays treatment.

If you feel exhausted and cannot seem to get your energy back no matter what you do, talk with your doctor about the possibility of CFS/ME.

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Medical Reviewer: Alana Biggers, M.D., MPH
Last Review Date: 2022 Feb 28
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THIS TOOL DOES NOT PROVIDE MEDICAL ADVICE. It is intended for informational purposes only. It is not a substitute for professional medical advice, diagnosis or treatment. Never ignore professional medical advice in seeking treatment because of something you have read on the site. If you think you may have a medical emergency, immediately call your doctor or dial 911.
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