Chronic Fatigue Syndrome (CFS)

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Have you ever had a day where you couldn’t perk up? Maybe you didn’t get enough sleep, or perhaps you were fighting a cold. Normally, this feeling fades when you address the cause. But for some, this temporary fatigue turns into a long-term issue. 

When you have chronic fatigue syndrome, you feel so physically and mentally exhausted that you can’t do everyday tasks like making yourself some lunch or showering. In this article, we’ll let you know what qualifies as chronic fatigue syndrome, how to know you have it, and what you can do to improve your symptoms.

Note: The content on Sleepopolis is meant to be informative in nature, but it shouldn’t be taken as medical advice, and it shouldn’t take the place of medical advice and supervision from a trained professional. If you feel you may be suffering from any sleep disorder or medical condition, please see your healthcare provider immediately.

Long Story Short

  • Chronic fatigue syndrome is a neurological condition that affects many systems in the body. It occurs most often in women between 20 and 45 years old.
  • The causes behind chronic fatigue syndrome are still unknown, but researchers are studying genetics, infection, stress, and sleep loss as possible origins.
  • Even though no cure exists, you may treat the symptoms of chronic fatigue syndrome with good sleep hygiene, physical therapy, rest periods, and medications approved by your provider.

What Is Chronic Fatigue Syndrome?

Chronic fatigue syndrome, or CFS, is a brain disorder that affects many systems in your body. (1,2,3) People with CFS are unable to do their daily tasks and about 25 percent of those affected cannot leave their bed or home for long stretches of time. (4,5

CFS Symptoms

As its name implies, chronic fatigue syndrome causes severe fatigue that doesn’t get better after resting. It can also generate other symptoms, including: (1,6,7)

  • Difficulty sleeping
  • Digestive issues
  • Muscle pain and weakness
  • Orthostatic intolerance 
  • Post-exertional malaise
  • Trouble concentrating and thinking

You may not experience everything on this list; CFS symptoms often vary from person to person, and symptoms come and go in waves.(1)

Orthostatic Intolerance, Defined

Orthostatic intolerance makes you dizzy or lightheaded when you change positions. (8) After exercise — either physical or mental — CFS can cause post-exertional malaise, or PEM.

Myalgic Encephalomyelitis

The term myalgic encephalomyelitis, or ME, is often used interchangeably with chronic fatigue syndrome, though some experts consider them to be separate conditions. (9)  The acronym “ME/CFS” is often used to generally describe both ME and CFS, as many patients experience symptoms of each. All categories of ME/CFS cause fatigue, cognitive impairment, PEM, difficulty sleeping, and orthostatic intolerance. (10)

How Common Is Chronic Fatigue Syndrome? 

“According to the Centers for Disease Control and Prevention (CDC), an estimated 836,000 to 2.5 million Americans live with ME/CFS, but most have not been formally diagnosed — and the challenges with the diagnosis is that ME/CFS symptoms overlap with other conditions,” Dr. Peter G. Polos, MD, pulmonologist, sleep medicine physician, and associate professor of sleep medicine tells Sleepopolis. (11

CFS can be more common in certain population groups, such as women aged 20 to 45 years at the time of diagnosis. (2) “What we know through research thus far is that it is more [commonly diagnosed] among women than men,” Polos explains. 

The CDC also tells us that about 90 percent of people with ME/CFS don’t know they have it. CFS can affect the ability to work, and through medical bills and lost income, costs the U.S. $17 to $24 billion every year. (5)

What Causes Chronic Fatigue Syndrome? 

Experts don’t yet know a definitive cause for chronic fatigue syndrome, and no current biomarkers (test results) can diagnose it. (12) But plenty have suggested possibilities. 

Genetic Predisposition

Some researchers believe ME/CFS has a genetic component, but no studies have yet confirmed it. Experts suggest thousands of people with ME/CFS would need to participate in a genetic study to confirm a genetic cause. But once they accomplish this, they believe they can categorize ME/CFS into subtypes and develop more specific treatments. (13,14,​​15

One study of 2382 cases found 14 genes showed up in 91 percent of the CFS cases they looked at. These genes are also associated with disease processes that have previously been linked with ME/CFS, such as: (14)

  • Autoimmune issues
  • Metabolic dysfunction 
  • Sleep disturbances
  • Stress vulnerability
  • Susceptibility to viruses and bacteria 


Sometimes CFS symptoms can follow a viral infection. In fact, about ten percent of people infected with Epstein-Barr virus, Ross River virus, or Coxiella burnetti develop ME/CFS-like fatigue, muscle aches, and digestive issues. (12,15) Some experts suggest CFS can be triggered when your body can’t get rid of a virus fast enough (called ineffectual viral clearance) and it builds up in your system. However, these results need to be confirmed by other studies. (14)


Most of the world is familiar with COVID-19 symptoms, from coughing and trouble breathing to fatigue and “brain fog.” (16) However, in 10 percent of people, COVID symptoms can last for more than 12 weeks after diagnosis. (17) This phenomenon has been named “long-COVID” and its symptoms hold many similarities to ME/CFS. While they are currently two different diagnoses, researchers are looking for evidence that long-COVID may cause ME/CFS. (18)

Immune System Disturbances

Up to 60 percent of ME/CFS patients also have an autoimmune disease. These two conditions share certain characteristics, like a higher prevalence in women and high levels of cytokines, which increase inflammation. Research also suggests chronic inflammation associated with autoimmune disorders may trigger ME/CFS. (14)


Some experts believe stress may spark ME/CFS symptoms. (15) Changes in your work situation, income, or interpersonal drama can all push your body to the limit. So far, research has yet to prove stress causes CFS, but studies have shown a connection between high stress and worsening symptoms. (19)

Sleep Loss

Sleep loss may also be a causative factor for chronic fatigue syndrome, but studies have yet to prove it. However, non-restorative sleep is one of the most frequently reported symptoms in people with CFS at 87 to 95 percent, and is used by many providers as a diagnostic measurement for the syndrome. (20

Metabolic Disorders

Your body converts food to energy through metabolic processes, but sometimes your metabolism doesn’t work quite right. When your cells can’t make enough energy from what you eat, it may provoke ME/CFS symptoms. (21) As muscle cells run out of energy and oxygen, fatigue, pain, and muscle twitching can ramp up. (22) More research is needed to understand if and how metabolic disorders may cause ME/CFS. (15)

Physical or Emotional Trauma

As a brain disorder, ME/CFS may be triggered by trauma. Research has shown adults with post-traumatic stress disorder (PTSD) can have long-term structural brain changes. (23) The symptoms of ME/CFS can themselves cause trauma, as one study found, which can heighten symptoms even more. (24)

Who Is at Risk for Chronic Fatigue Syndrome? 

Chronic fatigue syndrome can affect anyone, but you may be at higher risk if you are aged 20 to 45, caucasian, female, or single. (1,25) Groups who also have a higher CFS risk include those who have: (1,25)

  • Family history of anxiety
  • History of frequent colds or infections
  • History of fibromyalgia, multiple sclerosis, or rheumatoid arthritis

Fibromyalgia and Chronic Fatigue Syndrome

Fibromyalgia is a chronic syndrome that causes fatigue, pain throughout the body, and difficulty sleeping. (26) Sound familiar? Many have made the connection between fibromyalgia and CFS, as they share some symptoms. (27)

The two conditions part ways once fibromyalgia is diagnosed, because once your provider concludes your fatigue is caused by fibromyalgia, it can’t also be caused by CFS. (28) While fibromyalgia cannot be a true CFS risk factor, they are known as “sister conditions,” and providers must rule fibromyalgia out before diagnosing ME/CFS alone. (29,30)

Chronic Fatigue Syndrome Symptoms in Children

While CFS is more common in adults, children can receive this diagnosis as well. Symptoms in children closely mirror those in adults, reporting orthostatic intolerance, sleeping problems, and fatigue. However, kids report a few different symptoms, like headaches and stomach pain. Children don’t often complain of joint or muscle pain with CFS, but the onset of symptoms follows an infectious process more often than in adults. (31)

How Is Chronic Fatigue Syndrome Diagnosed? 

Chronic fatigue syndrome has no smoking gun. No lab tests or imaging can tell your healthcare provider with absolute certainty that you have CFS. (12) Instead, providers must use the process of elimination to establish a CFS diagnosis. They will perform a physical and mental assessment, ask about health and family health history, and order blood and urine tests. (1)

To receive a diagnosis, you must establish a few experiences: (7)

  • For at least six months, you have felt extreme fatigue and have not been able to complete routine activities that you could do before.
  • You don’t feel rested after a full night’s sleep. 
  • Your symptoms worsen after physical or mental activity (PEM).

You also must have one of these two symptoms for diagnosis: (7)

  • Issues with thinking and memory
  • Worse symptoms after changing position (orthostatic intolerance), including lightheadedness, dizziness, weakness, or fainting

Your provider may refer you to a specialist to rule out other conditions that can cause similar symptoms. (32

Potential Future Diagnostic Tools

Experts continue the search for a biomarker that can offer a more definitive CFS diagnosis. One study suggests cytokines in your blood may point to ME/CFS. Cytokines help regulate your immune system, but some can cause increased inflammation. (33,34) Higher levels of cytokines have been found in the blood and spinal fluid of CFS patients, but this test has not been approved for diagnosis yet. (33)

Another study review found brain abnormalities in many CFS patients via many different types of imaging, including MRI and PET scans. They also found CFS was correlated with higher brain area recruitment for cognitive tasks, which means the brain had to work harder when the subject was thinking. (35) While experts can’t yet promote imaging for CFS diagnosis, their research continues.

Treatment for Chronic Fatigue Syndrome

Chronic fatigue syndrome has no outright cure, but your provider may be able to help you manage your symptoms. (1,2,36) Polos recommends good sleep hygiene, physical therapy, activity, rest, diet changes, and medications.

Sleep Hygiene

“Adopting practices that promote regular and restful sleep can help manage fatigue and other symptoms,” Polos says. Sleep hygiene describes your sleep habits, and some good habits include: (37)

Physical Therapy

The CDC mentions physical therapy as a possible treatment for ME/CFS, but cautions that if you work your muscles too hard, you run the risk of post-exertional malaise. (38) “A physical therapist could help design an individualized exercise program that considers the patient’s physical needs and/or limitations,” Polos says. 

Balance Activity and Rest

“Also known as ‘pacing,’ one could manage their energy levels better or avoid worsening the symptoms after physical activity if they just balance the periods of activity and rest,” says Polos. The CDC suggests meditation, deep breathing, and relaxation therapy can also provide some relief from symptoms in their rest time. (39)

Adjust Your Diet

“Sometimes, changing one’s diet (i.e., removing a food item from their diet) could improve symptoms,” notes Polos. Studies confirm this can be the case, but found much better results in patients who followed a balanced diet that included: (40)

  • Foods rich in omega-3 fatty acid
  • Polyphenol-rich vegetables 
  • Whole grains high in fiber

The research suggests including these foods in your diet may be able to improve fatigue.

Ask About Medication

“For some, tricyclic antidepressants may be of benefit,” says Polos. A study review from 2017 found these medications were effective in some, but more recent research calls these results into question. (41,42) The CDC recommends nutritional supplements if you are lacking any vital nutrients like vitamins and minerals such as potassium or magnesium. Keep in mind, though, it’s always best to check with your provider before beginning any new therapy. (37)

“I would also encourage the patient to consult with their primary care physician (PCP) for an appropriate evaluation and diagnosis of the disease,” says Polos. Your provider can help you develop an individualized treatment plan. “Patients should always consult their PCP before starting/stopping any treatment,” Polos adds.

When to See a Doctor 

If you suspect you may have ME/CFS, your healthcare provider can help you find out what’s going on. If your symptoms are interfering with your daily life, you can seek out solutions as soon as you feel ready. While CFS may not be life-threatening for most, it can affect your quality of life. Advocate for yourself, and you may be able to improve your symptoms soon.


What is the best sleep aid for chronic fatigue syndrome?

“The best sleep aid for ME/CFS [and] sleep disorders would be to improve one’s sleep hygiene, especially because promoting regular and restful sleep can make a significant difference for those [coping with] ME/CFS,” says Polos.

Does magnesium help with CFS?

Magnesium has been suggested as a potential treatment for ME/CFS because of its role in many cellular processes, including energy production,” Polos says. “It has been reported that many individuals with CFS have a magnesium deficiency. For some, supplementation may be of benefit.” (43) Always be sure to talk to your provider before you start or stop any new medication or supplement.

The Last Word From Sleepopolis 

Chronic fatigue syndrome has the potential to disrupt your daily life. Beyond severe fatigue, CFS can cause brain fog, pain, and sleep loss, among other things. Even though it has no cure, you can treat your CFS symptoms and get some energy back. If you think these symptoms describe you, don’t hesitate to reach out to a healthcare provider for help.


  1. Chronic Fatigue Syndrome | CFS | MedlinePlus. MedlinePlus – Health Information from the National Library of Medicine. Accessed August 21, 2024.
  2. Cortes Rivera M, Mastronardi C, Silva-Aldana C, Arcos-Burgos M, Lidbury B. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Comprehensive Review. Diagnostics. 2019;(3):91. doi:10.3390/diagnostics9030091
  3. Wirth, K.J., Scheibenbogen, C. & Paul, F. An attempt to explain the neurological symptoms of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome. J Transl Med 19, 471 (2021).
  4. About ME/CFS | National Institutes of Health (NIH). National Institutes of Health (NIH). Published January 6, 2016. Accessed August 21, 2024.
  5. What is ME/CFS? | Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) | CDC. Centers for Disease Control and Prevention. Accessed August 21, 2024.
  6. Wirth K, Scheibenbogen C. A Unifying Hypothesis of the Pathophysiology of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Recognitions from the finding of autoantibodies against ß2-adrenergic receptors. Autoimmunity Reviews. 2020;(6):102527. doi:10.1016/j.autrev.2020.102527
  7. Symptoms of ME/CFS | Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) | CDC. Centers for Disease Control and Prevention. Accessed August 21, 2024.
  8. Garner R, Baraniuk JN. Orthostatic intolerance in chronic fatigue syndrome. Journal of Translational Medicine. 2019;(1). doi:10.1186/s12967-019-1935-y
  9. Understanding History of Case Definitions and Criteria  | Healthcare Providers | Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) | CDC. Centers for Disease Control and Prevention. Accessed August 31, 2024.
  10. Lim E-J, Son C-G. Review of case definitions for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Journal of Translational Medicine. 2020;(1). doi:10.1186/s12967-020-02455-0
  11. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) | CDC. Centers for Disease Control and Prevention. Accessed August 21, 2024.
  12. Ariza ME. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: The Human Herpesviruses Are Back! Biomolecules. 2021;(2):185. doi:10.3390/biom11020185
  13. Dibble JJ, McGrath SJ, Ponting CP. Genetic risk factors of ME/CFS: a critical review. Human Molecular Genetics. 2020;(R1):R117-R124. doi:10.1093/hmg/ddaa169
  14. Das S, Taylor K, Kozubek J, Sardell J, Gardner S. Genetic risk factors for ME/CFS identified using combinatorial analysis. Journal of Translational Medicine. 2022;(1). doi:10.1186/s12967-022-03815-8
  15. Possible Causes | Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) | CDC. Centers for Disease Control and Prevention. Accessed August 21, 2024.
  16. Coronavirus and the Nervous System | National Institute of Neurological Disorders and Stroke. National Institute of Neurological Disorders and Stroke. Accessed August 21, 2024.
  17. Shaheen N, Shaheen A. Long-term sequelae of COVID-19 (myalgic encephalomyelitis): An international cross-sectional study. Medicine. 2022;(45):e31819. doi:10.1097/md.0000000000031819
  18. Wostyn P. COVID-19 and chronic fatigue syndrome: Is the worst yet to come? Medical Hypotheses. Published online January 2021:110469. doi:10.1016/j.mehy.2020.110469
  19. Balinas C, Eaton-Fitch N, Maksoud R, Staines D, Marshall-Gradisnik S. Impact of Life Stressors on Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Symptoms: An Australian Longitudinal Study. International Journal of Environmental Research and Public Health. 2021;(20):10614. doi:10.3390/ijerph182010614
  20. Ferré A. Chronic fatigue syndrome and sleep disorders: Clinical associations and diagnostic difficulties. Neurología (English Edition). 2018;(6):385-394. doi:10.1016/j.nrleng.2015.11.020
  21. Hoel F, Hoel A, Pettersen IKN, et al. A map of metabolic phenotypes in patients with myalgic encephalomyelitis/chronic fatigue syndrome. JCI Insight. 2021;(16). doi:10.1172/jci.insight.149217
  22. Tornero-Aguilera JF, Jimenez-Morcillo J, Rubio-Zarapuz A, Clemente-Suárez VJ. Central and Peripheral Fatigue in Physical Exercise Explained: A Narrative Review. International Journal of Environmental Research and Public Health. 2022;(7):3909. doi:10.3390/ijerph19073909
  23. Mann SK. Posttraumatic Stress Disorder – StatPearls – NCBI Bookshelf. National Center for Biotechnology Information. Accessed August 21, 2024.
  24. Fennell PA, Dorr N, George SS. Elements of Suffering in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: The Experience of Loss, Grief, Stigma, and Trauma in the Severely and Very Severely Affected. Healthcare. 2021;(5):553. doi:10.3390/healthcare9050553
  25. Lacerda EM, Geraghty K, Kingdon CC, Palla L, Nacul L. A logistic regression analysis of risk factors in ME/CFS pathogenesis. BMC Neurology. 2019;(1). doi:10.1186/s12883-019-1468-2
  26. What is Fibromyalgia? – Symptoms & Treatment | NIAMS. National Institute of Arthritis and Musculoskeletal and Skin Diseases. Published June 2021. Accessed August 21, 2024.
  27. Zambolin F, Duro-Ocana P, Faisal A, et al. Fibromyalgia and Chronic Fatigue Syndromes: A systematic review and meta-analysis of cardiorespiratory fitness and neuromuscular function compared with healthy individuals. Juhl CB, ed. PLOS ONE. 2022;(10):e0276009. doi:10.1371/journal.pone.0276009
  28. Natelson BH. Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Fibromyalgia: Definitions, Similarities, and Differences. Clinical Therapeutics. 2019;(4):612-618. doi:10.1016/j.clinthera.2018.12.016
  29. Sapra A. Chronic Fatigue Syndrome – StatPearls – NCBI Bookshelf. National Center for Biotechnology Information. Accessed August 21, 2024.
  30. Maugars Y, Berthelot J-M, Le Goff B, Darrieutort-Laffite C. Fibromyalgia and Associated Disorders: From Pain to Chronic Suffering, From Subjective Hypersensitivity to Hypersensitivity Syndrome. Frontiers in Medicine. Published online July 14, 2021. doi:10.3389/fmed.2021.666914
  31. Symptoms and Diagnosis of ME/CFS in Children | Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) | CDC. Centers for Disease Control and Prevention. Accessed August 21, 2024.
  32. Diagnosis of ME/CFS | Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) | CDC. Centers for Disease Control and Prevention. Accessed August 21, 2024.
  33. Yang T, Yang Y, Wang D, et al. The clinical value of cytokines in chronic fatigue syndrome. Journal of Translational Medicine. 2019;(1). doi:10.1186/s12967-019-1948-6
  34. Liu C, Chu D, Kalantar‐Zadeh K, George J, Young HA, Liu G. Cytokines: From Clinical Significance to Quantification. Advanced Science. 2021;(15):2004433. doi:10.1002/advs.202004433
  35. Shan ZY, Barnden LR, Kwiatek RA, Bhuta S, Hermens DF, Lagopoulos J. Neuroimaging characteristics of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): a systematic review. Journal of Translational Medicine. 2020;(1). doi:10.1186/s12967-020-02506-6
  36. Treatment of ME/CFS | Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) | CDC. Centers for Disease Control and Prevention. Accessed August 21, 2024.
  37. Sleep Deprivation and Deficiency – Healthy Sleep Habits | NHLBI, NIH. NHLBI, NIH. Accessed August 21, 2024.
  38. Treating the Most Disruptive Symptoms First and Preventing Worsening of Symptoms  | Clinical Care of Patients | Healthcare Providers | Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) | CDC. Centers for Disease Control and Prevention. Accessed August 21, 2024.
  39. Treatment of ME/CFS | Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) | CDC. Centers for Disease Control and Prevention. Accessed August 21, 2024.
  40. Haß U, Herpich C, Norman K. Anti-Inflammatory Diets and Fatigue. Nutrients. 2019;(10):2315. doi:10.3390/nu11102315
  41. Richman S, Morris MC, Broderick G, Craddock TJA, Klimas NG, Fletcher MA. Pharmaceutical Interventions in Chronic Fatigue Syndrome: A Literature-based Commentary. Clinical Therapeutics. 2019;(5):798-805. doi:10.1016/j.clinthera.2019.02.011
  42. Castro-Marrero J, Sáez-Francàs N, Santillo D, Alegre J. Treatment and management of chronic fatigue syndrome/myalgic encephalomyelitis: all roads lead to Rome. British Journal of Pharmacology. 2017;(5):345-369. doi:10.1111/bph.13702
  43. Weigel B, Eaton-Fitch N, Passmore R, Cabanas H, Staines D, Marshall-Gradisnik S. A preliminary investigation of nutritional intake and supplement use in Australians with myalgic encephalomyelitis/chronic fatigue syndrome and the implications on health-related quality of life. Food & Nutrition Research. Published online June 7, 2021. doi:10.29219/fnr.v65.5730                                                            Polos, Peter G, MD. Personal Interview. August 15, 2024.
Abby McCoy

Abby McCoy

Abby McCoy is an RN of 16 years who has worked with adults and pediatric patients encompassing trauma, orthopedics, home care, transplant, and case management. She has practiced nursing all over the world from San Fransisco, CA to Tharaka, Kenya. Abby loves spending time with her husband, four kids, and their cat named Cat.