Symptoms of Chronic Fatigue Syndrome

The symptoms required to make the diagnosis of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) include fatigue, exercise intolerance, and unrefreshing sleep. However, many more symptoms are commonly experienced by people with this syndrome. Each person has his or her own mix of symptoms, so it's rare to find two cases that are just alike.

While some people are incapacitated by their symptoms of chronic fatigue syndrome, others can have less severe symptoms or episodes that come and go. By knowing all of the possible symptoms you can help your healthcare provider diagnose you properly. Tracking your symptoms can help you identify triggers. Perhaps most importantly, this awareness can help you see that you're not the only one experiencing these problems.

CFS symptoms
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Frequent Symptoms

In 2015, the National Academy of Medicine established that fatigue, post-exertional malaise, and sleep problems must be present in order to diagnose ME/CFS. In addition, either cognitive impairment (brain fog) or a worsening of symptoms while you are upright (orthostatic intolerance) must be noted.

Many people with chronic fatigue syndrome have symptoms that come and go and vary greatly in severity from day to day, week to week, or month to month. Other people may have constant symptoms with very little change over time.

Decreased Activity Level and Fatigue

You develop fatigue that was not present beforehand. You can't do the activities you used to do at your job, at school, at home, or in your social life. You feel an unusual tiredness that can be severe and incapacitating.

  • Your fatigue is not relieved by sleep or rest.
  • The fatigue is not due to strenuous physical labor.
  • Your fatigue significantly lowers your ability to function normally in most situations.
  • You have had this fatigue and drop in activity level for at least six months.

Post-Exertional Malaise

Post-exertional malaise (PEM) occurs after physical or mental activity that would not have resulted in feelings of tiredness or illness before you became sick.

Intense exhaustion and an upswing in other symptoms last for at least 24 hours, and sometimes for days or weeks.

An episode of PEM can range from mild—with extra fatigue, achiness, and brain fog—to completely disabling. The amount of exertion that can trigger it can be low, such as grocery shopping or taking a shower. You might describe it as how it feels to have mono or recover from a severe bout of influenza.

Sleep Problems

Unrefreshing sleep is a key symptom. You may wake up feeling like you haven't slept at all, no matter how long you slept. You might also have insomnia, with difficulty falling asleep or staying asleep.

Cognitive Impairment

Problems with memory and thinking ability seen in chronic fatigue syndrome are commonly called brain fog. Experts believe there is a slowing of information processing that leads to this symptom. This is not a required symptom for a diagnosis, but either it or orthostatic intolerance must be present for a diagnosis to be made.

Signs of "Brain Fog"

Symptoms of brain fog can range from mild to severe and vary from day to day. These are some of the specific problems you may have:

  • Short-term memory or concentration problems: These include losing your train of thought, forgetting what you were doing, or being unable to remember things you have heard or read.
  • Word use and recall problems: This can include difficulty finding the right word or remembering the names of things or people. You might also have impaired speech.
  • Impaired math and number ability: You may have a hard time calculating numbers or remembering number sequences or dates, for example.
  • Spatial disorientation: This may involve becoming lost easily or not remembering how to get somewhere familiar.
  • Difficulty multitasking not previously experienced

Orthostatic Intolerance

Orthostatic intolerance means that you have a worsening of your symptoms when you are standing or sitting upright. You might feel lightheaded, weak, or dizzy. You can have symptoms that make you think you are about to faint, such as blurred vision or seeing spots before your eyes. Again, you must have either this symptom or brain fog to meet the diagnostic criteria.


Pain is not a required symptom for diagnosis, but it is common in people with chronic fatigue syndrome. You may feel muscle aches, joint pain, or new or worsening headaches. Your pain is not caused by an injury. Here are some of the types of pain and changes in sensation that people report:

  • Pain amplification (hyperalgesia)
  • Pain from light touch, brushing against the skin, and/or temperature (allodynia)
  • New or worsening headaches
  • Morning stiffness
  • Earache
  • Numbness, tingling and/or burning sensations in the face or extremities (paresthesia)
  • Chest pains
  • Jaw pain (possibly TMJ, as an overlapping condition)

Flu-Like Symptoms

You may feel like you are sick all of the time or symptoms may recur frequently. Flu-like symptoms are common, but not everyone has them and they are not required for a diagnosis. They include:

  • Sore throat
  • Tender lymph nodes
  • Low-grade fever or low body temperature, including chills, night sweats, or excessive sweating
  • Chronic cough
  • Nausea or digestive problems

Sensitivities and Intolerances

You can have changes in what you can tolerate. These symptoms are not experienced by everyone and are not required for a diagnosis.

Rare Symptoms

There are many symptoms that people with ME/CFS experience that are not universal or required for a diagnosis. They may be due to overlapping conditions.

General Symptoms

  • Visual disturbances (blurring, light sensitivity, eye pain, worsening vision, dry eyes)
  • Dry mouth and eyes (sicca syndrome)
  • Rashes
  • Unexplained weight changes
  • Muscle twitching
  • Seizures
  • Recurrent infections
  • Frequent canker sores

Psychological Symptoms

  • Irritability
  • Anxiety
  • Panic attacks
  • Personality changes
  • Mood swings

Cardiovascular and Respiratory Symptoms

  • A feeling of an irregular heartbeat
  • Shortness of breath
  • Frequent, hard to treat respiratory infections

Common Overlapping Conditions

Overlapping conditions are separate conditions that commonly occur in people with ME/CFS, and they can bring about their own symptoms and/or compound those of chronic fatigue. These conditions often need to be diagnosed and treated separately in order for you to feel better, so be sure to talk to your healthcare provider about them.


As in any chronic illness, it is very common for people with chronic fatigue syndrome to experience depression, stress, and anxiety. While chronic fatigue syndrome is not a psychological condition, it is debilitating.

Good days or bad days can be unpredictable. You may experience ongoing challenges in your education, career, and personal life, as you work to balance how you feel about your obligations and desires. Many with ME/CFS describe feeling demoralized or even, at times, hopeless.

It is normal to have low periods while you adjust to the changes your condition imposes, but at some point, these can develop into major depression. You can work with your healthcare provider to get treatment for depression and anxiety. While this will not cure chronic fatigue syndrome, it can be helpful.

When to See a Healthcare Provider

You should see your healthcare provider if any of your symptoms are incapacitating or severe. The symptoms of ME/CFS are shared with many other conditions, some of which may require monitoring or immediate treatment.

If your symptoms are generally mild and fluctuating, you may question your need for an evaluation. Even if your symptoms are severe, you may have friends or family members who think you are exaggerating and don't understand what you are experiencing. But chronic fatigue syndrome is more than just being tired—it's feeling sick.

Chronic Fatigue Syndrome Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Old Woman

When your symptoms last for more than two weeks, continue to get worse, or if you have a pattern of recurrences (even if you returned to feeling normal between episodes), it's time to make an appointment.

While the diagnosis of ME/CFS won't be made until you have the symptoms for more than six months, you shouldn't delay seeking care and assessment. ME/CFS is diagnosed by symptoms and excluding other conditions. You may discover your symptoms are due to a condition that has an effective treatment available.

Keep a record of your symptoms, noting dates they began or worsened and what may have triggered them. Some of them may resolve if they are due to an overlapping condition that is being treated, but some symptoms may remain and need to be addressed.

Chronic fatigue syndrome is often misunderstood, even by some healthcare providers. You may need to be persistent to ensure your symptoms get appropriate attention. 

Frequently Asked Questions

  • What are the main symptoms of ME/CFS?

    The symptoms most often associated with myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) include:

    • Ongoing fatigue lasting at least six months
    • Exercise intolerance
    • Unrefreshing sleep

    However, symptoms vary from person to person and many other symptoms are often attributed to ME/CFS, so it's important to keep a log of what you're experiencing to help yourself and your healthcare provider identify potential triggers.

  • Is rash a symptom of chronic fatigue syndrome?

    Yes, in some cases, symptoms can include skin rashes, itching, and hives, as well as bone, muscle, or joint pain.

  • How do I know if I have chronic fatigue syndrome?

    Chronic fatigue syndrome differs from general fatigue or tiredness after mental or physical exertion. Instead, it is characterized as extreme exhaustion, where even everyday errands, activities, or keeping up with work can cause severe fatigue, dizziness, and difficulty thinking. Your healthcare provider can use several different evaluation tools to help you come to a diagnosis.

  • What does a ME/CFS crash feel like?

    A CFS crash can feel like an episode of worsening symptoms, including extreme physical exhaustion and severe mental fatigue. Experiencing a crash may mean you can't perform your daily activities or may not even be able to get out of bed. It may take days or weeks to recover from a CFS crash.

  • How long does ME/CFS last?

    ME/CFS is generally considered to be a lifelong condition for which there is no standard treatment. However, many factors can improve quality of life for those with ME/CFS, such as lifestyle changes, stress management techniques, medications, sleep aids, alternative medicine, and therapy.

5 Sources
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.
  1. Rowe PC, Underhill RA, Friedman KJ, et al. Myalgic encephalomyelitis/chronic fatigue syndrome diagnosis and management in young people: A primerFront Pediatr. 2017;5:121. doi:10.3389/fped.2017.00121

  2. Centers for Disease Control and Prevention. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: IOM 2015 Diagnostic Criteria.

  3. Review of the Evidence on Other ME/CFS Symptoms and Manifestations. In: Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome; Board on the Health of Select Populations; Institute of Medicine. Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington, DC: National Academies Press (US).

  4. American Myalgic Encephalomyelitis and Chronic Fatigue Syndrome Society. Symptoms of ME/CFS.

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

Additional Reading
  • Symptoms. Centers for Disease Control and Prevention.
  • Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness. Washington: The National Academies Press.

By Adrienne Dellwo
Adrienne Dellwo is an experienced journalist who was diagnosed with fibromyalgia and has written extensively on the topic.