Evidence browser

Energy MetabolismPost-Exertional Malaise

The High Costs of Low-Grade Inflammation: Persistent Fatigue as a Consequence of Reduced Cellular-Energy Availability and Non-adaptive Energy Expenditure.

Lacourt, Tamara E, Vichaya, Elisabeth G, Chiu, Gabriel S et al.·Frontiers in behavioral neuroscience·2018

This study explores why people with ME/CFS experience persistent fatigue by examining how inflammation in the body may damage cells' ability to produce energy. The researchers propose that chronic inflammation forces cells to switch to a less efficient energy-production method, while at the same time the body may be spending energy at rates it cannot sustain, creating an energy crisis. Sleep problems and disrupted body rhythms may also play a role in this imbalance.

Old muscle in young body: an aphorism describing the Chronic Fatigue Syndrome.

Pietrangelo, Tiziana, Fulle, Stefania, Coscia, Francesco et al.·European journal of translational myology·2018

This study found that muscles in people with ME/CFS show patterns similar to muscles in elderly people, even though the patients are young. The researchers discovered problems with how muscles use energy, handle calcium, and produce new muscle protein. Importantly, the findings suggest that appropriate physical activity may actually help rather than harm, though the right type and intensity still need to be determined.

E3 PreliminaryReviewPEM requiredReview-Narrative

Infection Elicited Autoimmunity and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: An Explanatory Model.

Blomberg, Jonas, Gottfries, Carl-Gerhard, Elfaitouri, Amal et al.·Frontiers in immunology·2018

This study proposes that ME/CFS may develop when a person's immune system mistakenly attacks their own body after an infection, particularly affecting energy production in muscles and the brain. The researchers suggest that some people may have a genetic tendency to develop these harmful immune responses, especially when their gut bacteria are out of balance. When exposed to a triggering infection, the immune system can begin attacking proteins involved in energy metabolism and nerve function, leading to the exhaustion and post-exertion symptoms that characterize ME/CFS.

E3 PreliminaryDiagnosticPEM requiredMethods-Paper

Cardiopulmonary Exercise Test Methodology for Assessing Exertion Intolerance in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Stevens, Staci, Snell, Chris, Stevens, Jared et al.·Frontiers in pediatrics·2018

This study explains how doctors can properly test ME/CFS patients using a special exercise test called CPET (cardiopulmonary exercise test) done on two consecutive days. The first test measures how much exercise a patient can do, while the second test 24 hours later shows how much the patient's performance has dropped due to post-exertional malaise (PEM)—the symptom flare that happens after exertion. This two-day approach objectively demonstrates one of the key features of ME/CFS: the inability to recover normal function after exercise.

E3 PreliminaryDiagnosticPEM not requiredMethods-Paper

Myalgic Encephalomyelitis (ME) or What? An Operational Definition.

Twisk, Frank·Diagnostics (Basel, Switzerland)·2018

This paper proposes a clear, practical definition of ME (myalgic encephalomyelitis) to help doctors reliably identify and study the condition. The authors argue that ME is a distinct multi-system illness characterized by severe muscle exhaustion after minimal activity, neurological symptoms (like brain fog and autonomic problems), and a pattern of symptom fluctuation and relapse over months or years. Having a precise definition is essential so researchers can study the right patients and develop effective treatments.

Unraveling the Molecular Determinants of Manual Therapy: An Approach to Integrative Therapeutics for the Treatment of Fibromyalgia and Chronic Fatigue Syndrome/Myalgic Encephalomyelitis.

Espejo, José Andrés, García-Escudero, María, Oltra, Elisa·International journal of molecular sciences·2018

This review examines how manual therapy—such as massage and physical manipulation—might help people with fibromyalgia and ME/CFS by studying what happens at the cellular and molecular level. The authors argue that manual therapy could work by triggering the body's natural healing responses, and they suggest it might be particularly helpful for ME/CFS patients because it can gently condition muscles without requiring strenuous exercise that typically worsens symptoms.

E3 PreliminaryCohortPEM unclearCross-Sectional

Integration of DNA methylation & health scores identifies subtypes in myalgic encephalomyelitis/chronic fatigue syndrome.

de Vega, Wilfred C, Erdman, Lauren, Vernon, Suzanne D et al.·Epigenomics·2018

Researchers studied 70 women with ME/CFS and found that their DNA showed different chemical patterns in immune cells. These chemical differences matched up with specific symptoms and health problems that patients reported. The study identified four distinct subtypes of ME/CFS, each with its own pattern of DNA changes and symptom profile, suggesting that ME/CFS may not be one uniform condition but rather several related conditions with different underlying biology.

E3 PreliminaryMechanismPEM unclearCase-Control

[Comparison of differential metabolites in urine of the middle school students with chronic fatigue syndrome before and after exercise].

Chi, Ai-Ping, Wang, Zi-Nan, Shi, Bing et al.·Zhongguo ying yong sheng li xue za zhi = Zhongguo yingyong shenglixue zazhi = Chinese journal of applied physiology·2018

This study looked at chemicals in the urine of teenagers with ME/CFS before and after exercise to understand how their bodies process energy differently. Researchers found that people with ME/CFS had abnormal levels of several metabolites (chemical byproducts), and these changes got worse after exercise, suggesting their bodies struggle to recover from physical activity.

Energy MetabolismPost-Exertional Malaise

Autonomic dysfunction and HPV immunization: an overview.

Blitshteyn, Svetlana, Brinth, Louise, Hendrickson, Jeanne E et al.·Immunologic research·2018

This review looked at case reports from multiple countries describing people who developed serious symptoms after HPV vaccination, including extreme fatigue, pain, dizziness, and cognitive problems. These symptoms are similar to those seen in ME/CFS, POTS, and other conditions. The authors suggest that in some genetically vulnerable people, the vaccine might trigger an immune system response that affects the nervous system, but they emphasize that timing alone doesn't prove the vaccine caused the illness.

Mechanisms Explaining Muscle Fatigue and Muscle Pain in Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): a Review of Recent Findings.

Gerwyn, Morris, Maes, Michael·Current rheumatology reports·2017

This review examines why ME/CFS patients experience muscle fatigue and pain. Researchers found that several biological problems may contribute to these symptoms: damaged cellular energy factories (mitochondria), harmful stress molecules building up in the body, and reduced production of protective proteins. These problems together may explain why ME/CFS patients get tired quickly and struggle with exercise.

E3 PreliminaryMechanismPEM requiredMechanistic

Neural consequences of post-exertion malaise in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Cook, Dane B, Light, Alan R, Light, Kathleen C et al.·Brain, behavior, and immunity·2017

This study examined what happens in the brains of ME/CFS patients after exercise. Researchers asked 15 patients and 15 healthy people to exercise for 30 minutes, then used brain imaging to see how their brains worked before and 24 hours after exercise. ME/CFS patients' symptoms got much worse after exercise, their thinking and memory got worse, and their brain activity changed in specific ways—showing that exercise triggered real, measurable changes in how their brains functioned.

E3 PreliminaryMechanismPEM requiredCross-Sectional

Exercise - induced changes in cerebrospinal fluid miRNAs in Gulf War Illness, Chronic Fatigue Syndrome and sedentary control subjects.

Baraniuk, James N, Shivapurkar, Narayan·Scientific reports·2017

Researchers studied brain fluid from people with Gulf War Illness and chronic fatigue syndrome (CFS) before and after exercise to understand why exercise makes symptoms worse. They found that exercise changes certain molecules called microRNAs in the brain fluid, and these changes were different in people with CFS compared to Gulf War Illness patients. This suggests that the biological reasons these conditions cause post-exertional exhaustion may be different, even though the symptoms look similar.

E3 PreliminaryGuidelinePEM requiredGuideline

Myalgic encephalomyelitis: International Consensus Criteria.

Journal of internal medicine·2017

This guideline establishes internationally agreed-upon criteria for diagnosing ME/CFS, helping doctors around the world recognize the condition consistently. It brings together expert knowledge to create clear standards for who has ME/CFS based on symptoms like post-exertional malaise (worsening after activity), sleep problems, cognitive difficulties, and pain. Having a shared definition makes it easier for patients to get accurate diagnoses and for researchers to study the same condition across different countries.

E3 PreliminaryCohortPEM not requiredCase-Control

Two hundreds cases of ASIA syndrome following silicone implants: a comparative study of 30 years and a review of current literature.

Colaris, Maartje J L, de Boer, Mintsje, van der Hulst, Rene R et al.·Immunologic research·2017

This study compared 200 patients with silicone breast implants who developed autoimmune and inflammatory symptoms (a condition called ASIA) across two time periods—100 patients in 2014 and 100 historical patients from the 1980s–1990s. The researchers found that the symptoms remained similar over 30 years, including fatigue, joint pain, brain fog, and fever. About half of the patients who had their implants removed experienced symptom improvement.

E3 PreliminaryGuidelinePEM requiredGuideline

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Diagnosis and Management in Young People: A Primer.

Rowe, Peter C, Underhill, Rosemary A, Friedman, Kenneth J et al.·Frontiers in pediatrics·2017

This guide helps doctors understand and diagnose ME/CFS in children and teenagers. ME/CFS causes extreme tiredness and makes it hard for young people to do physical or mental activities—with symptoms often getting worse after even small efforts and lasting for days or longer. The guide explains that there is no single test for ME/CFS, so doctors must diagnose it based on symptoms and by ruling out other conditions, and recommends that treatment focus on finding the right balance between rest and activity.

E3 PreliminaryMechanismPEM unclearMechanistic

Detection of Urine Metabolites in a Rat Model of Chronic Fatigue Syndrome before and after Exercise.

Shao, Changzhuan, Ren, Yiming, Wang, Zinan et al.·BioMed research international·2017

Researchers used rats exposed to stress and exercise to model ME/CFS and then measured chemicals in their urine before and after exercise. They found abnormalities in how the rats' bodies produce energy and process hormones, particularly in molecules called sphingosine and a hormone precursor called 21-hydroxypregnenolone. These findings suggest that ME/CFS may involve disrupted energy metabolism and problems with the body's stress-response system.

Energy MetabolismImmune SystemPost-Exertional Malaise

E3 PreliminaryTrialPEM not requiredRCT

Neuromuscular Strain Increases Symptom Intensity in Chronic Fatigue Syndrome.

Rowe, Peter C, Fontaine, Kevin R, Lauver, Megan et al.·PloS one·2016

Researchers tested whether stretching nerves and soft tissues in the legs—by doing a simple straight leg raise test—could trigger or worsen ME/CFS symptoms. Patients with ME/CFS who received the real stretch experienced more pain, concentration problems, and lightheadedness during and 24 hours after the test, compared to those who received a fake stretch and compared to healthy people. This suggests that physical strain on nerves and tissues may be one reason why ME/CFS symptoms get worse with activity.

E3 PreliminaryReviewPEM not requiredReview-Narrative

Exercise-induced mitochondrial dysfunction: a myth or reality?

Ostojic, Sergej M·Clinical science (London, England : 1979)·2016

Exercise is usually good for your cells' energy factories (mitochondria), but this review asks whether extremely intense or exhausting exercise might actually damage them instead. The authors explore how very hard exercise could harm mitochondrial function and suggest this might explain some cases of chronic fatigue syndrome and muscle problems.

E3 PreliminaryDiagnosticPEM requiredMethods-Paper

Assessment of ME/CFS (Myalgic Encephalomyelitis/Chronic Fatigue Syndrome): A Case Study for Health Care Providers.

Brimmer, Dana J, Jones, James F, Boneva, Roumiana et al.·MedEdPORTAL : the journal of teaching and learning resources·2016

This study created an educational course to help medical students, physician assistants, and nursing students better understand ME/CFS and how to care for patients with this condition. The course used videos and slide presentations to teach about ME/CFS symptoms, diagnosis, and management. Students who completed the course showed improved knowledge about ME/CFS and developed more empathy for patients living with this illness.