What Is Chronic Fatigue Syndrome?

Chronic fatigue syndrome (CFS) is a long-term condition that affects several systems in your body. CFS—sometimes called myalgic encephalomyelitis or ME—causes extreme, unrelenting fatigue, sleep problems, muscle pain, and cognitive difficulties. Unfortunately, the condition is complicated for researchers to fully understand, making it also difficult to diagnose and treat. 

It’s hard to say exactly how many people have CFS since many people don't receive an official diagnosis. However, research estimates that 836,000 to 2.5 million Americans live with CFS each year. There’s no single cause of CFS, but many people develop symptoms after experiencing another illness or infection or living under prolonged periods of stress.


The symptoms of CFS can vary from person to person. You may have symptoms that are mild or severe. It's also possible for symptoms to come and go. If you have CFS, you might experience one or more of the following symptoms:

  • Unexplainable fatigue: The most common symptom of CFS, fatigue is more than just feeling tired all the time. You might feel exhausted after completing daily activities, not feel energized even after getting good sleep, or have trouble getting out of bed in the morning.
  • Difficulty sleeping: You may struggle to fall asleep or stay asleep at night despite being so intensely fatigued.
  • Pain: It's common to experience several different types of pain, across more than one part of your body. This can include muscle aches, joint pain, headaches, and a sore throat.
  • Dizziness: CFS can cause you to feel dizzy, lightheaded, weak, or faint when sitting or standing.
  • Cognitive impairment: It may be hard for people with CFS to concentrate or remember things easily.
  • Post-exertional malaise (PEM): People with CFS may notice a distinct worsening of symptoms, or a severe “crash,” after forcing themselves to do any physical or mental activity.


Researchers haven’t determined why some people develop CFS. They believe that immune system inflammation and chemical changes in the body may be to blame. Experts theorize that one of the following factors can trigger the onset of CFS symptoms:

  • Infections, such as the Epstein-Barr virus
  • Changes in immune system functioning
  • High levels of stress
  • Hormonal changes

While anyone of any age can develop CFS, the condition tends to be more common in adults over the age of 40. You may also be at an increased risk of having symptoms if you have a family history of CFS and were assigned female at birth.


If you think you have symptoms of CFS, it's a good idea to visit your healthcare provider for testing. It can be difficult to diagnose CFS because many other health conditions can cause similar symptoms. CFS also can’t be detected by routine testing—like blood work and imaging tests. However, these tests can rule out other possible causes of your symptoms, so many healthcare providers will order them during your diagnostic process.

Your healthcare provider will also take a complete medical history, perform a physical exam, and discuss your symptoms—including their severity, frequency, and onset. It's common for primary care providers to refer you to a specialist during the diagnostic process. Based on your symptoms, you may be working with a rheumatologist (a doctor who specializes in the muscles, joints, and bones) or a sleep specialist.

During diagnosis, your healthcare provider will look to confirm if you have the three hallmark symptoms of CFS: fatigue, post-exertional malaise, and difficulty sleeping. These symptoms must be present for at least six months. If you have these three symptoms, your provider will also need to confirm if you have one of the following symptoms in order to give you an official diagnosis for CFS:

  • Cognitive impairment, such as trouble thinking, inability to focus, or memory problems
  • Orthostatic intolerance, such as dizziness or weakness when standing or sitting up

If you receive a diagnosis for CFS, your healthcare provider will work with you to find a treatment plan that helps you better manage the condition.


There’s no cure for chronic fatigue syndrome. However, treatment can help you manage your symptoms and restore your ability to function in daily life. Your healthcare provider can recommend the following treatment options:

  • Medications: There is no medication that is currently approved to treat CFS. However, your healthcare provider can prescribe you medications to treat individual symptoms. These may include antidepressants, pain relievers, and sleep aids.
  • Therapy: Cognitive behavioral therapy (CBT) is a type of talk therapy that can help you reframe negative thoughts about your condition, improve overall fatigue levels, and practice stress management techniques to reduce symptoms.
  • Pacing: A lifestyle change that your provider may suggest is activity pacing or management. This means identifying your personal limits for how much physical and mental activity you can comfortably do in a day and staying within those boundaries. As your symptoms improve, you can slowly start building up stamina again. Pacing can prevent you from overexerting yourself as you live with CFS.

How to Prevent Chronic Fatigue Syndrome Crashes

Because researchers still don’t know the exact underlying cause of CFS, it's hard to understand how to prevent CFS from occurring. However, there are some things you can do to reduce the frequency and severity of CFS flares—or periods of time where you experience active symptoms. These flares are commonly known as "crashes."

  • Manage your medications: Work with your provider to find the right combination of medicines to improve your quality of life. Stick to the regimen once you find one that helps you.
  • Know your limits: Resist the temptation to power through your symptoms. Pushing yourself to do more than you comfortably are able to can leave you with worsening symptoms for days or weeks.
  • Minimize stress: Physical and mental stress can leave you feeling more depleted than normal. Some research suggests that having strong stress management skills and a healthy support system can reduce fatigue in people with CFS.
  • Delegate tasks: If there are responsibilities you can regularly assign to family and friends, there will be less for you to manage on a daily basis, which can leave you with more time for rest. Ask trusted loved ones if they would be willing to support you on your treatment journey.

Comorbid Conditions

There are several health conditions that may occur alongside CFS—which are known as comorbid conditions. Some may be caused by the same inflammation and overactive immune responses that triggered your CFS, while others may occur as a result of your CFS symptoms. These conditions may include:

Living With Chronic Fatigue Syndrome

CFS won’t limit your life expectancy, but the often-debilitating nature of the illness—along with its unpredictability—can make living with the condition extremely difficult. CFS isn’t necessarily permanent, but since there are no treatments aimed at curing it, it's hard to know when you'll experience crashes and how long symptoms will last.

Some experts advise people with CFS to focus on small goals and milestones rather than looking too far ahead. In other words, it can help to celebrate a victory like being able to add an extra 10 minutes to your daily exercise routine without it negatively affecting your symptoms.

Additionally, you can improve your quality of life with CFS by trying the following strategies:

  • Finding a trusted provider: Having a healthcare professional who thoroughly understands CFS and advocates for your best interests will take some of the pressure off of you.
  • Shore-up support: Whether it’s friends and family or an online support group, you will benefit from having a few people in your life who empathize with your condition and are committed to being there for you during your treatment journey.
  • Prioritizing therapy: Receiving consistent counseling can help you cope with the mental health side effects of having CFS. A trained therapist can also help you explain your condition to friends and family and educate you about stress management techniques.
  • Talking to your employer: If you are still able to work but need accommodations, work with your employer to see which ones can be made. If you cannot work, you may be eligible for disability benefits.
  • Using energy-saving devices: Some experts recommend relying on equipment like motorized wheelchairs when you need to perform a taxing activity. This can help you conserve energy for other tasks during the day.

Keep in mind that new research is being done all the time to improve outcomes for people with CFS. Newer treatments for CFS include antiviral drugs and immunotherapy. If you think you might be a candidate for a new treatment, talk with your provider to learn about your options.

Was this page helpful?
8 Sources
Health.com 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.
  1. MedlinePlus. Chronic fatigue syndrome.

  2. Office on Women's Health. Chronic fatigue syndrome.

  3. Centers for Disease Control and Prevention. Symptoms of ME/CFS.

  4. Centers for Disease Control and Prevention. Myalgic encephalomyelitis/chronic fatigue syndrome: Possible causes.

  5. Centers for Disease Control and Prevention. Diagnosis of ME/CFS.

  6. Centers for Disease Control and Prevention. Treatment of ME/CFS.

  7. Sapra A, Bhandari P. Chronic fatigue syndrome. In: StatPearls. StatPearls Publishing; 2022.

  8. Nagy-Szakal D, Williams BL, Mishra N, et al. Fecal metagenomic profiles in subgroups of patients with myalgic encephalomyelitis/chronic fatigue syndromeMicrobiome. 2017;5(1):44. doi:10.1186/s40168-017-0261-y

Related Articles