What Is Chronic Fatigue Syndrome?

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Chronic fatigue syndrome (CFS) is a condition that involves profound, long-term fatigue, brain fog, and other symptoms. Diseases commonly associated with CFS include anxiety and depression, fibromyalgia, irritable bowel syndrome (IBS), and allergies or drug sensitivities.

A syndrome is a group of recognizable signs and symptoms that appear to be related, but the direct cause is not clear. A disorder is a group of signs and symptoms involving disruption in how the body functions. With CFS, healthcare providers may use the terms "syndrome" and "disorder" interchangeably. CFS is also known as myalgic encephalomyelitis (ME) or ME/CFS.

This article discusses the symptoms, causes, diagnosis, and treatment options for chronic fatigue syndrome.

A woman feeling fatigue and exhaustion

Maca and Naca / Getty Images

How Do You Know If You Have Chronic Fatigue Syndrome?

Everyone feels tired sometimes. And almost everyone experiences fatigue on occasion. But CFS is much more than that. It's an unexplained and overwhelming physical and mental exhaustion that makes pushing through the most basic activities hard. Then you crash. You rest, and you try to sleep, but nothing helps.

Here are some examples of what it's like to have CFS:

  • You have trouble carrying out simple daily tasks such as grocery shopping or doing laundry, which has been happening for months.
  • You can't concentrate and feel like you're in a brain fog.
  • You're having trouble sleeping through the night.
  • Whatever the activity, it takes longer to recover than it should.
  • You find yourself staying home to rest far too often.
  • Sometimes, it's exhausting to think about getting out of bed and dressing up.
  • Fatigue lowers your quality of life.

There are many potential causes for fatigue, and symptoms of CFS can overlap with symptoms of other conditions. The only way to verify your diagnosis is to see a healthcare professional.

Chronic Fatigue Syndrome Symptoms

Symptoms can develop slowly or start suddenly, ranging from mild to severe. They can come and go or last for weeks, months, or years.

Symptoms of CFS may include:

  • A drop in activity level and fatigue that lasts six months or more
  • Extreme physical and mental fatigue that gets worse if you're active yet doesn't improve with rest or sleep
  • Sleep problems such as trouble falling asleep, frequent waking, and feeling sleepy during the day
  • Muscle and joint aches and pains, headache, sore throat
  • Tender lymph nodes in the neck or armpits
  • Chills and night sweats
  • Dizziness or weakness upon standing
  • Problems with memory, concentration, and slow reaction time
  • Sound and light sensitivity
  • Heart palpitations, shortness of breath

CFS vs. Fibromyalgia

CFS and fibromyalgia are chronic, complex conditions of an unclear cause that can significantly impact quality of life. Both affect women more than men. Both involve a variety of symptoms, including fatigue and widespread pain. However, the predominant symptom of CFS is chronic fatigue, while fibromyalgia is pain. It's possible to be diagnosed with both.

Possible Causes of Chronic Fatigue Syndrome

The exact cause of CFS is not clear. It may be a combination of genetic and environmental factors that include:

CFS affects about 1 million people in the United States. Anyone can develop CFS, but risk factors include:

  • Female sex: Women are affected three times as often as men
  • Age: Often occurs between the ages of 10 and 19 or 30 and 39, but the average age at onset is 33
  • Race: Rates may be higher among Black and Latinx people than among other groups

How Is Chronic Fatigue Syndrome Diagnosed?

There are no specific tests for CFS, so the diagnostic process can be lengthy. Your healthcare provider will likely start by taking a medical history and performing a physical exam. To check for other conditions that can cause similar symptoms, the following steps may include:

Currently, blood tests can't determine that you have CFS. But that could change. Researchers developed a blood test that could find biomarkers that accurately detect people with CFS. More research is needed, but this could improve the diagnostic process in the future.

Diagnosis requires having these three symptoms:

  • Substantial reduction in the ability to engage in pre-illness levels of activity (lasts more than six months, plus new fatigue not related to exertion and not relieved by rest)
  • Post-exertional malaise (when symptoms worsen for a time after light physical or mental activity)
  • Unrefreshing sleep

It also requires one of these symptoms:

  • Cognitive impairment (problems with concentration, memory, and reaction time)
  • Orthostatic intolerance (dizziness and weakness while standing up)

Is Chronic Fatigue Syndrome Real?

CFS is real, despite a controversial history. Lack of understanding has led some to theorize that the condition is psychological. Its name, definition, and diagnostic criteria have changed over the years. Many questions remain, but there is evidence that it's a biological illness, not a psychological disorder.

Chronic Fatigue Syndrome Complications

Living with CFS can affect your overall quality of life, including a substantial impairment of work or school activities, social isolation, reduced mobility, chronic pain, anxiety, and more. Living with a chronic illness can affect your mental health and increase the risk of depression.

Chronic Fatigue Syndrome Treatment: Managing Symptoms

There's no standard treatment for CFS. However, you can manage specific symptoms. A healthcare provider may refer you to other providers, such as a sleep specialist, who can provide additional help with symptom management.

Activity Management

Activity management (or pacing) involves identifying your limits for physical and mental activities. Writing in an activity/symptom journal can help uncover the activities that have the most significant impact. This way, you can make a plan to balance activities with ample time for rest.

You can also find ways to make those activities more accessible, such as by alternating tasks, dividing tasks into smaller segments, and sitting rather than standing when possible.

Lifestyle Adjustments

While not directly treating CFS, certain lifestyle changes may help you feel better. For example:

  • Create good, consistent sleep habits.
  • Maintain a balanced diet for overall good health.
  • Perform stretching and moving exercises.
  • Use organizers, calendars, and apps to help with memory problems.
  • Listen to your body so you don't overextend yourself.


If needed, a healthcare provider may recommend medications for certain symptoms, such as:

  • Mild pain relievers
  • Sleep aids
  • Anti-anxiety and antidepressant drugs

Some providers may prescribe stimulants, which are usually used to treat attention deficit hyperactivity disorder (ADHD), to target the fatigue of CFS. These drugs should be used cautiously, as they can lead to a "push-and-crash cycle" that can potentially make matters worse.

CAM Therapies to Supplement CFS Treatment

When it comes to complementary and alternative medicine (CAM) therapy for CFS, research is lacking. That doesn't mean you won't find some helpful.

Remember that even natural ingredients can be harmful in excess and many can interact with other medications. Before adding extra vitamins or herbal supplements to your diet, speak with a provider.

Other therapies that may help manage symptoms and improve overall well-being include:

  • Massage
  • Meditation
  • Deep breathing
  • Muscle relaxation therapy
  • Movement therapies such as yoga, tai chi, and stretching
  • Acupuncture

Chronic Fatigue Syndrome Support and Resources

If you're having trouble coping with CFS, you're not alone. Living with chronic fatigue and pain takes a toll. Here are a few places to seek information and support:

Outlook for Chronic Fatigue Syndrome

CFS is a long-term debilitating condition. Still, some people do return to their previous levels of functioning. Others make only a partial recovery. While many do not fully recover, they can continue finding ways to keep symptoms under control. Children and teenagers may have a better chance of full or partial recovery than adults, and there may be a benefit to early diagnosis and good management.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Ann Pietrangelo
Ann Pietrangelo is a freelance writer, health reporter, and author of two books about her personal health experiences.