Chronic fatigue syndrome is a complex, long-term illness that impacts on a wide range of systems throughout the body. It causes a wide array of symptoms that might present differently for each person with the condition.

The condition is also known as myalgic encephalomyelitis (ME). There might be 17 – 24 million people worldwide with chronic fatigue syndrome (CFS).

Many people who have CFS rely on medical treatment to help alleviate symptoms and may have to learn a new approach to daily living that reduces the impact of the condition.

There is no simple cure, and treatment tends to focus on managing symptoms.

CFS is complex and can impact a wide range of systems and functions.

There is a long list of potential symptoms. Many of these symptoms may appear similar to other conditions, making a thorough diagnosis difficult but important.

Core symptoms

Doctors first focus on identifying the primary (core) symptoms of the CFS. These may change slightly from person to person, but for a doctor to reach a diagnosis of CFS, they need to note these three of the following core symptoms.


Fatigue is an extreme lack of energy. Doctors officially recognize extreme fatigue as a significantly reduced ability to perform activities that were once routine before the onset of CFS. The fatigue in CFS often lasts 6 months or longer.

In the context of CFS, it is important to note that a doctor does not use “fatigue” to refer to a person feeling tired or unmotivated at a certain point in the day. People with CFS may not be able to shake this fatigue. Sleep or rest does not replenish energy and may even make symptoms worse in some individuals.

The fatigue in CFS may be so severe that it interferes with daily function.

Post-exertional malaise

Post-exertional malaise (PEM) is another core symptom of CFS. PEM is a deterioration of symptoms after physical or mental exertion.

When a person with PEM engages in too much physical or mental activity, they will experience worsening symptoms over the next few hours or days, and will often feel intense exhaustion as they recover.

A person experiencing PEM may describe it as having their internal battery completely and immediately drained. When they push themselves too far, it can harm the body. Therefore, people with CFS must pace themselves throughout the day to avoid overexertion.

Sleep disorders

People with CFS also experience a range of sleep disorders, including unrefreshing sleep. Even after a long night of rest, they wake up tired.

There are a number of sleep disorders that can potentially lead to sleep that does not replenish energy, including:

  • insomnia, which is trouble falling and staying asleep
  • hypersomnia, which is excessive sleep
  • sleep apnea, in which a person stops breathing as they sleep
  • light sleep, a disorder that means an individual never enters the deeper stages of sleep
  • fragmented sleep, consisting of frequently waking up and falling back asleep
  • phase shifting, in which a person may not be able to fall asleep until sunrise
  • involuntary spasms in the legs or arms
  • restless legs
  • nightmares with vivid dreams that disrupt sleep
  • night sweats

Along with the three above core symptoms that are present, one or both of the following must also be present for the diagnosis of CFS:

Cognitive impairment

Difficulties with thought processes can occur in many forms for people with CFS.

People with cognitive impairment may have memory problems. They may not be able to remember recent conversations or might always be losing belongings. Movies and books can become extremely difficult to follow all the way through.

Thinking or simple problem solving may severely reduce energy levels in a person with CFS.

Other people with this syndrome may become lost in familiar settings, such as their own neighborhood. They may require intense effort to remember simple directions, names, or even written instructions.

CFS can cause different cognitive impairments in different people.

Orthostatic intolerance

These are symptoms that occur when moving from lying on your back to sitting or standing, including dizziness, lightheadedness, or feeling faint. This also might cause a person to feel as if they are seeing spots or experience blurred vision.

Other symptoms

Other symptoms known to occur in CFS include the following:


Almost all people with CFS experience some form of pain or discomfort, ranging from headaches and cramps to severe, widespread pain.

People with CFS most commonly describe the pain sensation as a general ache or soreness in the muscles and joints. This pain may occur in one area then move to another. Headaches are also common.

Other pain descriptors are common as well, including pain that people describe as:

  • shooting
  • stabbing
  • burning or tingling
  • throbbing

Someone with CFS may also be highly sensitive to light, touch, heat, or cold. Experiencing these sensations to an extreme extent may cause pain.

Other potential symptoms

There are many other possible symptoms of CFS, ranging in severity, and may change from person to person.

Possible symptoms include:

  • sore throat
  • enlarged lymph nodes
  • muscle twitching
  • rashes
  • canker sores
  • anxiety or panic attacks
  • depression
  • high stress levels
  • dizziness
  • flu-like symptoms
  • saying words wrong
  • low or high body temperature
  • numbness
  • tinnitus
  • extreme symptoms of premenstrual syndrome (PMS)
  • altered senses, such as visual problems
  • lack of sex drive, sexual impotence
  • hair loss
  • weight changes
  • heart palpitations
  • chest pain
  • seizures
  • paralysis

There is no single known cause for CFS.

The trigger for the disorder may vary in each person, and it may be something as simple as flu or extreme stress after which CFS sets in. There is still much speculation surrounding CFS, and research has not yet confirmed the cause.

A few factors may increase the risk for CFS, such as stress levels, age, and sex.

According to the Office on Women’s Health, women are two to four times more likely than men to experience CFS.

Some researchers are studying the effect of alterations in immune system function that may have associations with CFS.

Research continues as to the risk factors for developing CFS as a condition. These factors do not necessarily cause the disease, but there appears to be a link between them.

A thorough diagnostic process for people with CFS is highly important but difficult.

Doctors may not recognize some symptoms or may confuse them with the symptoms of other disorders.

A CFS diagnosis often occurs by eliminating the possibility of other disorders, which can be a long process.

Diagnostic methods for CFS might improve in the coming years. A study posted to the journal Scientific Reports found specific molecules that occurred at altered levels in the blood samples of people with CFS. However, at the current time, there is no specific laboratory test for confirming a diagnosis of CFS.

This research may help make future diagnoses of chronic fatigue syndrome easier and more accurate.

Current treatment methods cannot cure every person with CFS. For most people, a course of treatment revolves around managing or treating the individual symptoms of the disorder.

As symptoms vary from person to person, a range of treatments are available to respond to the wide array of physical symptoms. No treatments are always effective for every person with CFS, but most people have at least a few measures available for their set of symptoms.

Doctors may prescribe various medications to help manage individual symptoms, generally starting with treatment for the most troublesome symptoms to help restore daily living. They will usually prescribe a low dose of any medication at the start of a course and gradually increase the amount if needed.

People with CFS tend to be highly sensitive to chemicals and medications. Any medication or supplement might cause an unwanted reaction. Starting with low doses helps the doctor closely monitor any side effects and find the lowest possible dose for providing relief.

Certain experimental treatments are also available to treat CFS. Drugs including rituximab and Ampligen may help treat a component of CFS. These medications focus on underlying issues in the immune system that may have links to the syndrome.

The success of each treatment method can vary greatly and largely depends on the symptoms occurring for that particular person.

For many people with CFS, lifestyle changes are an important part of symptom management.

Many people with CFS have to find ways to manage their activity levels. They may need to schedule and spread out activities they know will drain them of energy, and might also have to give up activities involving a lot of exertion.

Depending on which symptoms present, methods of managing daily life with CFS include:

  • calendars, journals, or daily planners to help with memory issues
  • therapy to find emotional and psychological coping strategies
  • relaxation techniques, such as breathing exercises, meditation, or massage
  • a well-balanced, nutritious diet
  • specific nutritional supplements, if you are found to have a deficiency in one or more specific nutrients

The stigma around the condition

Until recently, many people in both the medical community and wider society misunderstood CFS.

Many doctors wrote the condition off as unwillingness to be productive.

The medical community now understands that CFS is a life-changing, complex disorder. Doctors and researchers are investigating new ways to diagnose and treat CFS, as well as improving understanding among people with the condition as to how they can self-manage.

Medical scientists do not yet fully understand CFS.

The condition impacts a wide range of systems and commonly causes intense, unshakeable fatigue, a malaise after physical or mental exertion, and sleep disorders, among a wide variety of other symptoms. The effects of the syndrome are different for each person.

While the cause is still unknown, some researchers link the condition to the immune system.

A thorough diagnosis is key and often complicated. A doctor will rule out other conditions until CFS becomes clear.

Medications are available to treat certain symptoms, and research is underway to tackle the condition at its core. In the meantime, people with CFS must carefully manage their lifestyles to adapt to the reduced energy.


Is there a diet that can help support a person with CFS?


Health experts recommend a well-balanced, nutritious diet for everyone, but a person with CFS could especially benefit.

Avoiding substances that can make CFS symptoms worse, such as alcohol or caffeine, may help prevent feelings of tiredness or anxiety. Making sure important vitamins and nutrients are present in the diet will also allow the body to function more efficiently, potentially helping to reduce CFS symptoms.

Keeping a food diary that monitors food consumption as well as any related symptoms that occur may help in determining which foods do or do not work best with CFS.

Stacy Sampson, DO Answers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.