What Is Chronic Fatigue Syndrome?


Chronic fatigue syndrome (CFS), also known as myalgic encephalitis (ME), is a condition involving extreme exhaustion that affects both the body and the brain.1  

While the exact reason why people develop CFS is relatively unknown, a diagnosis usually occurs after being unwell with another condition.1 

CFS can be debilitating and disruptive to your daily life, especially without proper management.  However, there are some lifestyle adaptations that can ease your struggle with CFS.2

Causes of chronic fatigue syndrome

Some known causes of chronic fatigue syndrome include:

  • A physical injury or accident1
  • A traumatic event or loss1
  • Genetics1
  • Poor food/energy metabolism1 
  • Epstein-Barr virus (which causes glandular fever/mononucleosis)3
  • Long COVID (a possible after-effect of COVID-19)4

Signs and symptoms of chronic fatigue syndrome

Extreme fatigue 

The main symptom of CFS is excessive tiredness and lack of energy that occurs for at least 6 months. You may find it difficult to do everyday tasks, such as showering, cleaning and cooking, without experiencing overwhelming exhaustion. CFS will usually have an impact on your work or school life too.5

Chronic pain

With CFS, you may experience aches and pains on a regular/consistent basis. Pain can occur in your:

  • Muscles 
  • Joints 
  • Head (a migraine-like feeling)
  • Skin (when pressure is applied)5

Sleep problems 

CFS may also make it difficult for you to:

  • Fall asleep
  • Stay asleep
  • Feel rejuvenated after sleep5

Poor memory and inattentiveness 

Poor memory and inattentiveness due to CFS may start as a mild inconvenience, but can become particularly troubling if you start to forget important information. These symptoms also tend to worsen after a long day of mentally overexerting yourself.5

Mental health problems 

Having CFS may make you prone to developing mental health conditions like depression or anxiety. It may also exacerbate pre-existing mental health problems, as living with CFS can be difficult and limiting.5 

Management and treatment for chronic fatigue syndrome

There is no 100% effective treatment that works for everyone with CFS, so your treatment plan may include some trial and error until you find a solution that works for you.2 The main way to manage CFS is to reduce the number of daily activities you are undertaking. ME/CFS patients will have less energy than the average child or adult, so it is important to be aware of your limits, which is sometimes referred to as an ‘energy budget.5 

Common diet and lifestyle adjustments recommendations to people with chronic fatigue include:

  • Eating a varied, nutritionally-balanced diet6
  • Adding more energy-dense foods to your diet, such as protein (e.g. meat, fish, eggs or beans) and carbohydrates (e.g. potatoes, bread, rice or pasta)6
  • Taking vitamins and other dietary supplements (within the recommended daily amount)
  • Participating in low-impact exercise daily (such as walking or swimming)5
  • Getting plenty of sleep at night and resting during the daytime if and when you need to5

You may also find it helpful to have certain accommodations made at your place of work or study, such as a chair to prevent you from standing up for long periods of time.5  

You should also reach out to your friends and family for support if you're struggling to manage your condition. Consulting your doctor is especially important if you are struggling with a mental health condition, as they may offer you solutions such as prescribed medication or counselling services to help.2 

Diagnosis of chronic fatigue syndrome

There is no specific diagnostic test for CFS - your doctor will take an account of the symptoms you are experiencing and your medical background. You may also be offered a blood test in order to eliminate other possible causes of your symptoms.2  

Other conditions which may present similarly to ME/CFS include:

Your healthcare provider will usually reach a diagnosis of CFS through a process of elimination if no other cause is apparent. A CFS diagnosis is usually only given as a last resort as more serious health conditions must be ruled out before you can move forward with treatment.2  

Risk factors

Risk factors for developing CFS include: 

  • Being assigned female at birth (AFAB)
  • Being between 20 and 50 years old
  • Getting an infection 
  • Having a mental health condition 
  • Sustaining a significant injury 
  • Having a family member with CFS
  • Having a difficult childhood or experiencing a traumatic event in adulthood7


Post-exertional malaise (PEM) is a state ME/CFS patients can enter after doing too much activity without adequate rest. Overexertion can lead to PEM flare-ups and worsening of fatigue, pain and mental fog. PEM can begin up to 2 days after activity and lasts for 1 day to a few weeks. It may cause you to require bed rest until you start to feel better.Orthostatic intolerance may also occur in some ME/CFS patients. You may have this if you find it difficult to stand for a long period of time without experiencing a racing heart, profuse sweating, nausea or feeling like you might fall over.5  


How common is chronic fatigue syndrome?

Estimates say that every 1 in 500 people in the UK are affected by CFS. The most commonly affected demographics are AFAB individuals and those in their early 20’s to late 40’s.8 

Can chronic fatigue syndrome be prevented?

There is no way to prevent yourself from developing CFS. You can only manage your symptoms to prevent your condition from worsening.2

When should I see a doctor?

You should see a doctor if you are experiencing symptoms that are profoundly impacting your daily life. This may include having difficulty with work or school, or performing daily functions without experiencing debilitating exhaustion and/or pain.1


Getting a diagnosis of CFS can feel like your life and abilities are suddenly limited. Dealing with exhaustion, pain and other mental symptoms can be draining, so it is important to take it easy as part of managing your condition. Ignoring your condition, or doing more than your symptoms allow you to do, can have short- and long-term impacts on your health, so it is important to treat and manage your CFS effectively. 


  1. Chronic fatigue syndrome - Symptoms and causes [Internet]. Mayo Clinic. [cited 2023 Apr 6]. Available from: https://www.mayoclinic.org/diseases-conditions/chronic-fatigue-syndrome/symptoms-causes/syc-20360490 
  2. Bateman L, Bested AC, Bonilla HF, Chheda BV, Chu L, Curtin JM, et al. Myalgic encephalomyelitis/chronic fatigue syndrome: essentials of diagnosis and management. Mayo Clinic Proceedings [Internet]. 2021 Nov [cited 2023 Apr 6];96(11):2861–78. Available from: https://linkinghub.elsevier.com/retrieve/pii/S0025619621005139 
  3. Glandular fever symptoms and treatments [Internet]. NHS Inform. [cited 2023 Apr 6]. Available from: https://www.nhsinform.scot/illnesses-and-conditions/infections-and-poisoning/glandular-fever 
  4. Five things to know about Long Covid and chronic fatigue syndrome [Internet]. Gavi, the Vaccine Alliance; 2023 Jan 4 [cited 2023 Apr 6]. Available from: https://www.gavi.org/vaccineswork/five-things-know-about-long-covid-and-chronic-fatigue-syndrome 
  5. Treating the most disruptive symptoms first and preventing worsening of symptoms | clinical care of patients | healthcare providers | myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) [Internet]. CDC; 2021 [cited 2023 Apr 6]. Available from: https://www.cdc.gov/me-cfs/healthcare-providers/clinical-care-patients-mecfs/treating-most-disruptive-symptoms.html 
  6. Myalgic encephalomyelitis (Or encephalopathy) / chronic fatigue syndrome(ME/CFS) [Internet]. BDA; [cited 2023 Apr 6]. Available from: https://www.bda.uk.com/resource/chronic-fatigue-syndrome-diet.html 
  7. Risk factors for chronic fatigue syndrome (CFS) [Internet]. Winchester Hospital; [cited 2023 Apr 6]. Available from: https://www.winchesterhospital.org/health-library/article?id=19245 
  8. Chronic Fatigue Syndrome [Internet]. NHS George Eliot Hospital; [cited 2023 Apr 6] Available from: https://www.geh.nhs.uk/directory-of-services/specialties-and-services/c/chronic-fatigue-syndrome/#:~:text=The%20National%20Institute%20of%20Health,in%20the%20UK%20have%20CFS 
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Amy Murtagh

BSc Veterinary Bioscience - Bachelors of Science, University of Glasgow

Amy is a recent graduate from Glasgow's School of Biodiversity, One Health and Veterinary Medicine with a particular interest in science communication in these subject areas.

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