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Topic

Post-Exertional Malaise

Domain: Exercise Physiology

PEM-relevant research
70 studies in the atlas

The hallmark symptom of ME/CFS — worsening of symptoms following minimal physical or cognitive exertion.

What We Know

  • Two-day CPET studies demonstrate objective, reproducible impairment of VO2 max and anaerobic threshold on the second test day — unique to ME/CFS. This distinguishes ME/CFS from deconditioning. PEM is now required for diagnosis under most modern criteria.

What We Think

  • Research into immune activation, gene expression changes, and metabolomics during and after exertion challenges is illuminating PEM mechanisms.

What We Don't Know

  • The biological mechanism of PEM is not fully understood. The role of exercise intolerance vs. true pathological worsening is still debated in some clinical circles.

Studies in this Topic

E0 ConsensusPEM ✓Higher confidenceReviewed

Beyond Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: Redefining an Illness

Institute of Medicine Committee on the Diagnostic Criteria for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome·National Academies Press·2015

The US Institute of Medicine reviewed over 9,000 scientific articles to establish new diagnostic criteria for ME/CFS. The report introduced SEID (Systemic Exertion Intolerance Disease) as a proposed name and established that ME/CFS is a serious, chronic, complex systemic disease. New criteria require PEM, unrefreshing sleep, plus cognitive impairment or orthostatic intolerance.

DiagnosticsPost-Exertional Malaise
E0 ConsensusPEM ?Higher confidenceReviewed

Diagnosis and Management of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Grach, Stephanie L, Seltzer, Jaime, Chon, Tony Y et al.·Mayo Clinic proceedings·2023

This review explains how doctors can diagnose and manage ME/CFS, a serious illness that causes extreme tiredness and other symptoms, often starting after an infection. The authors note that ME/CFS shares many similarities with long COVID, the condition some people experience after having COVID-19. They provide practical guidance to help healthcare providers recognize and treat this condition.

Long COVID OverlapPost-Exertional Malaise
E0 ConsensusPEM ✓Moderate confidenceReviewed

Chronic Fatigue Syndrome: Diagnosis, Treatment, and Future Direction.

Graves, B Sue, Patel, Mitsu, Newgent, Hailey et al.·Cureus·2024

ME/CFS is a serious illness that causes extreme tiredness that doesn't improve with rest and often gets worse with activity. People with ME/CFS also struggle with brain fog, pain, sleep problems, and immune system issues. Right now, doctors don't have a simple blood test or scan to diagnose ME/CFS, which makes it hard to identify and treat the condition properly.

BiomarkersCognitive ImpairmentPost-Exertional MalaiseImmune Dysregulation
E0 ConsensusPEM ✓Moderate confidenceReviewed

Key Pathophysiological Role of Skeletal Muscle Disturbance in Post COVID and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Accumulated Evidence.

Scheibenbogen, Carmen, Wirth, Klaus J·Journal of cachexia, sarcopenia and muscle·2025

This review brings together recent research showing that ME/CFS involves problems in the muscles themselves, particularly damage to mitochondria (the energy-producing structures inside cells) and an imbalance of salt and calcium in muscle tissue. When muscles don't get enough oxygen, they switch to a less efficient way of making energy, which causes sodium (salt) to build up inside cells, triggering calcium overload that damages mitochondria. This cascade of damage may explain why patients experience severe fatigue and feel much worse after exercise.

Post-Exertional Malaise
E0 ConsensusPEM ?Moderate confidenceReviewed

Advancing Research and Treatment: An Overview of Clinical Trials in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) and Future Perspectives.

Seton, Katharine A, Espejo-Oltra, José A, Giménez-Orenga, Karen et al.·Journal of clinical medicine·2024

This review examined research studies testing various treatments for ME/CFS, including medications and supplements that target different aspects of the illness like immune function, metabolism, and gut health. The authors found that current treatments mainly manage symptoms rather than address the root causes, with very few patients recovering fully. They emphasize that better-designed clinical trials are urgently needed to find treatments that actually work and can be used in real-world medical practice.

Post-Exertional MalaiseImmune Dysregulation
E0 ConsensusPEM ✓Moderate confidenceReviewed

Towards an understanding of physical activity-induced post-exertional malaise: Insights into microvascular alterations and immunometabolic interactions in post-COVID condition and myalgic encephalomyelitis/chronic fatigue syndrome.

Haunhorst, Simon, Dudziak, Diana, Scheibenbogen, Carmen et al.·Infection·2025

This review examines why people with ME/CFS and long COVID feel much worse after physical activity—a condition called post-exertional malaise. The researchers found that when these patients exercise, their bodies struggle to use oxygen properly and produce energy efficiently, likely due to problems with tiny blood vessels and lingering immune activation. This causes a buildup of harmful substances like lactate and triggers further inflammation and exhaustion.

Post-Exertional Malaise
E0 ConsensusPEM ✓Moderate confidenceReviewed

Pain-Related Post-Exertional Malaise in Myalgic Encephalomyelitis / Chronic Fatigue Syndrome (ME/CFS) and Fibromyalgia: A Systematic Review and Three-Level Meta-Analysis.

Barhorst, Ellen E, Boruch, Alexander E, Cook, Dane B et al.·Pain medicine (Malden, Mass.)·2022

This review examined whether people with ME/CFS and fibromyalgia experience increased pain after exercise. Researchers combined data from 15 studies and found that yes, patients do have more pain after physical activity than healthy people do—especially when pain was measured 8-72 hours later. This confirms that pain is a real and significant part of post-exertional malaise (the worsening of symptoms after activity).

Post-Exertional Malaise
E0 ConsensusPEM ✓Moderate confidenceReviewed

The persistence of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) after SARS-CoV-2 infection: A systematic review and meta-analysis.

Dehlia, Ankush, Guthridge, Mark A·The Journal of infection·2024

Researchers looked at studies of people with Long COVID to see how many also meet the diagnostic criteria for ME/CFS. They found that about half of Long COVID patients have symptoms that match ME/CFS, including severe fatigue, sleep problems, muscle and joint pain, and post-exertional malaise (feeling much worse after physical activity). This suggests that Long COVID and ME/CFS may be very similar conditions, at least in some patients.

Sleep DysfunctionPost-Exertional Malaise
E0 ConsensusPEM ?Moderate confidenceReviewed

Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): Where will the drugs come from?

Toogood, Peter L, Clauw, Daniel J, Phadke, Sameer et al.·Pharmacological research·2021

ME/CFS is a serious illness causing extreme fatigue that doesn't improve with rest, along with pain, sleep problems, and difficulty thinking clearly. This review looks at what we currently know about ME/CFS, how doctors diagnose it, and what treatments exist today. The authors examined past research to identify promising targets for new medicines that could help treat ME/CFS in the future.

Post-Exertional MalaiseImmune Dysregulation
E0 ConsensusPEM ✓Moderate confidenceReviewed

Exercise Pathophysiology in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Postacute Sequelae of SARS-CoV-2: More in Common Than Not?

Joseph, Phillip, Singh, Inderjit, Oliveira, Rudolf et al.·Chest·2023

This review compares how the body responds to exercise in people with long COVID (PASC) and ME/CFS, two conditions that share similar symptoms like extreme tiredness and worsening symptoms after activity. Researchers found that both conditions show similar abnormalities in heart function, blood flow, and breathing during exercise that go beyond simple deconditioning or being out of shape. These shared patterns suggest both conditions may involve similar underlying biological problems, which could help doctors develop better tests and treatments.

Post-Exertional Malaise
E0 ConsensusPEM ✓Moderate confidenceReviewed

The evidence base for physiotherapy in myalgic encephalomyelitis/chronic fatigue syndrome when considering post-exertional malaise: a systematic review and narrative synthesis.

Wormgoor, Marjon E A, Rodenburg, Sanne C·Journal of translational medicine·2021

This review looked at 18 studies testing physiotherapy (physical therapy) for ME/CFS, paying special attention to post-exertional malaise (PEM)—the worsening of symptoms after activity that defines ME. The researchers found that treatments appearing to help patients with general chronic fatigue showed less benefit when studied in patients with stricter ME/CFS definitions that include PEM, and may actually cause harm in ME patients. The study warns that physical therapy approaches effective for milder conditions should not be used for ME patients with prominent PEM.

Post-Exertional Malaise
E0 ConsensusPEM ✓Moderate confidenceReviewed

Gut Microbiome and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Insights into Disease Mechanisms.

Nikolova, Ralitsa, Donchev, Deyan, Vaseva, Katya et al.·International journal of molecular sciences·2025

This review examines the connection between gut bacteria and ME/CFS, a condition characterized by exhaustion that worsens after activity. The authors explain how an imbalance in gut bacteria may damage the intestinal barrier, allowing bacterial particles to enter the bloodstream and trigger inflammation throughout the body. They also discuss how changes in gut bacteria might affect the brain, contributing to the brain fog and cognitive problems many ME/CFS patients experience.

Post-Exertional MalaiseImmune DysregulationGut Microbiome
E0 ConsensusPEM ✓Moderate confidenceReviewed

[Myalgic encephalomyelitis or chronic fatigue syndrome].

Brinth, Louise, Nielsen, Henrik, Varming, Kim et al.·Ugeskrift for laeger·2019

ME/CFS is a serious condition that causes extreme tiredness affecting both mind and body, along with pain, sleep problems, difficulty thinking clearly, and a symptom called post-exertional malaise where activity makes symptoms worse. Research has found changes in patients' cells, hormones, immune systems, and how their bodies process energy, which could lead to better ways to diagnose and treat this condition.

Metabolic DysfunctionBiomarkersPost-Exertional MalaiseImmune Dysregulation
E0 ConsensusPEM ✓Higher confidenceReviewed

Review of case definitions for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Lim, Eun-Jin, Son, Chang-Gue·Journal of translational medicine·2020

This study reviewed how ME/CFS has been defined and diagnosed over the past 34 years, examining 25 different case definitions created by researchers. The researchers found that these definitions fall into four main categories and emphasize different key symptoms—some focus on a viral cause, others on inflammation, and some on multiple system problems. Understanding these different approaches helps doctors and patients recognize that ME/CFS is complex and may require more than one way to diagnose it.

Cognitive ImpairmentPost-Exertional Malaise
E0 ConsensusPEM ✓Moderate confidenceReviewed

Pathological Mechanisms Underlying Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Missailidis, Daniel, Annesley, Sarah J, Fisher, Paul R·Diagnostics (Basel, Switzerland)·2019

ME/CFS is a complex condition affecting multiple body systems, and researchers are working to understand what causes it. This review shows that evidence points to problems in the immune system, nervous system, muscle function, metabolism, and gut health in ME/CFS patients. Because patients experience different symptoms and may develop the condition in different ways, finding reliable diagnostic tests remains a key challenge that researchers are actively pursuing.

Post-Exertional MalaiseImmune Dysregulation
E0 ConsensusPEM ✓Higher confidenceReviewed

Meta-analysis investigating post-exertional malaise between patients and controls.

Brown, Abigail, Jason, Leonard A·Journal of health psychology·2020

This study looked at research from multiple studies to understand how common post-exertional malaise (PEM) is in people with ME/CFS. Post-exertional malaise is when symptoms get worse after physical or mental activity. The researchers found that people with ME/CFS are about 10 times more likely to experience post-exertional malaise than people without the condition, suggesting it is a key feature of ME/CFS.

Post-Exertional Malaise
E0 ConsensusPEM ✓Moderate confidenceReviewed

A review on cognitive behavorial therapy (CBT) and graded exercise therapy (GET) in myalgic encephalomyelitis (ME) / chronic fatigue syndrome (CFS): CBT/GET is not only ineffective and not evidence-based, but also potentially harmful for many patients with ME/CFS.

Twisk, Frank N M, Maes, Michael·Neuro endocrinology letters·2009

This review challenges the common medical recommendation to treat ME/CFS with cognitive behavioral therapy (CBT) and graded exercise therapy (GET). The authors argue that these treatments are not effective for ME/CFS and may actually harm many patients by worsening their symptoms, particularly through exercise-induced post-exertional malaise—a characteristic crash that occurs after physical activity. Instead, the review suggests that ME/CFS has biological causes that make intense exercise potentially dangerous rather than therapeutic.

Post-Exertional Malaise
E0 ConsensusPEM ✓Moderate confidenceReviewed

Differential Characteristics and Comparison Between Long-COVID Syndrome and Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

Ivanovska, Mariya, Homadi, Maysam Salim, Angelova, Gergana et al.·Biomedicines·2025

This review compared Long-COVID (illness after COVID-19) and ME/CFS (chronic fatigue syndrome), which share similar symptoms like extreme tiredness, difficulty thinking clearly, and problems with the nervous system. While both conditions likely involve immune system problems, viral persistence, and blood vessel issues, they appear to have some differences in how they develop. Currently, there is no cure for either condition, though lifestyle management and rehabilitation help some people.

Cognitive ImpairmentPost-Exertional MalaiseImmune Dysregulation
E0 ConsensusPEM ✓PreliminaryMachine draft

Posttreatment Lyme disease syndrome and myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review and comparison of pathogenesis.

Bai, Natalie A, Richardson, Christie S·Chronic diseases and translational medicine·2023

This review examined 18 studies comparing two similar chronic illnesses: posttreatment Lyme disease syndrome (PTLDS), which affects about 10% of Lyme disease patients even after antibiotic treatment, and ME/CFS. Both conditions cause severe fatigue, cognitive problems, pain, and sleep issues that last for months or years. The researchers found that patients with PTLDS experience many of the same symptoms as ME/CFS patients, suggesting these different illnesses may develop through similar biological pathways in the body.

Post-Exertional Malaise
E0 ConsensusPEM ✓PreliminaryMachine draft

The search for a blood-based biomarker for Myalgic Encephalomyelitis/ Chronic Fatigue Syndrome (ME/CFS): from biochemistry to electrophysiology.

Clarke, Krista S P, Kingdon, Caroline C, Hughes, Michael Pycraft et al.·Journal of translational medicine·2025

This review looked at recent research on finding a simple blood test that could definitively diagnose ME/CFS, which currently takes years and relies on ruling out other diseases. Scientists have found several promising approaches—including measuring immune cell properties, checking how blood cells respond to stress, and detecting metabolic changes—that show they can tell ME/CFS patients apart from healthy people and others with different illnesses. However, these tests need more testing in larger groups and practical refinement before doctors can use them in everyday care.

Post-Exertional Malaise
E0 ConsensusPEM ✓PreliminaryMachine draft

Epigenetic reprograming in myalgic encephalomyelitis/chronic fatigue syndrome: A narrative of latent viruses.

Apostolou, Eirini, Rosén, Anders·Journal of internal medicine·2024

This review examines how viruses, particularly Epstein-Barr virus, may cause lasting changes to how our cells work in ME/CFS patients. The authors found that in about 70% of ME/CFS cases, the illness begins after a viral infection, and viruses can hide in the body while triggering long-term problems with energy, thinking, and immune function. Understanding these viral-triggered changes could help explain why different patients experience ME/CFS differently and may lead to better treatments.

Post-Exertional MalaiseImmune Dysregulation
E0 ConsensusPEM ✓PreliminaryMachine draft

A scoping review of 'Pacing' for management of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): lessons learned for the long COVID pandemic.

Sanal-Hayes, Nilihan E M, Mclaughlin, Marie, Hayes, Lawrence D et al.·Journal of translational medicine·2023

This review looked at 17 studies about 'pacing'—a strategy where people with ME/CFS carefully manage their activity level to avoid making symptoms worse. The researchers found that studies on pacing had very different designs and results: some showed pacing helped, some showed no benefit, and a few suggested it could be harmful. The evidence so far isn't strong enough to confidently say whether pacing works best for everyone.

Post-Exertional Malaise
E0 ConsensusPEM ✗Higher confidenceMachine draft

Does the effect of cognitive behavior therapy for chronic fatigue syndrome (ME/CFS) vary by patient characteristics? A systematic review and individual patient data meta-analysis.

Kuut, T A, Buffart, L M, Braamse, A M J et al.·Psychological medicine·2024

This study combined data from 8 clinical trials involving 1,298 people with ME/CFS to see whether cognitive behavior therapy (CBT) works and who benefits most from it. Researchers found that CBT did help reduce fatigue, improve daily functioning, and increase physical activity—but the amount of benefit varied depending on patient characteristics like age, how much disability someone had, and their activity patterns. Younger patients, those with less severe disability at the start, and those with fluctuating activity patterns saw the most improvement.

Post-Exertional Malaise
E0 ConsensusPEM ✓Moderate confidenceMachine draft

Myalgic encephalomyelitis/chronic fatigue syndrome and fibromyalgia - overlap, differences, and emerging insights.

Murovska, Modra, Krumina, Angelika, Araja, Diana et al.·Journal of translational medicine·2026

ME/CFS and fibromyalgia are two different but often overlapping illnesses that cause severe fatigue, pain, and other debilitating symptoms. While they share many similarities, ME/CFS has a distinctive feature called post-exertional malaise—where activity makes symptoms dramatically worse for hours or days—while fibromyalgia does not. This review shows that the two conditions have different immune system patterns and may require different treatment approaches.

Cognitive ImpairmentPost-Exertional MalaiseImmune Dysregulation
E0 ConsensusPEM ✓Moderate confidenceMachine draft

The Emerging Role of Gut Microbiota in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): Current Evidence and Potential Therapeutic Applications.

Varesi, Angelica, Deumer, Undine-Sophie, Ananth, Sanjana et al.·Journal of clinical medicine·2021

Many people with ME/CFS experience stomach and digestive problems alongside their fatigue and pain. This review explores how the bacteria living in our gut might be different in ME/CFS patients and could be contributing to symptoms. The researchers found that people with ME/CFS tend to have fewer types of gut bacteria compared to healthy people, and they discuss how treating the gut microbiome might help reduce ME/CFS symptoms overall.

Post-Exertional Malaise
E0 ConsensusPEM ✓Moderate confidenceMachine draft

Redox imbalance links COVID-19 and myalgic encephalomyelitis/chronic fatigue syndrome.

Paul, Bindu D, Lemle, Marian D, Komaroff, Anthony L et al.·Proceedings of the National Academy of Sciences of the United States of America·2021

This review examines how COVID-19 and ME/CFS may share similar biological problems, particularly an imbalance in how the body handles harmful molecules called free radicals. Both conditions appear to involve problems with inflammation, energy production in cells, and a slowed metabolism. While this research shows these biological abnormalities exist in both illnesses, more studies are needed to understand exactly how they work together and how to treat them.

NeuroinflammationPost-Exertional Malaise
E0 ConsensusPEM ✓Moderate confidenceMachine draft

Insights into the Complex Biological Network Underlying Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Dudova, Dobrina, Bozhkova, Martina, Petrov, Steliyan et al.·International journal of molecular sciences·2025

This review brings together research showing that ME/CFS involves multiple body systems going wrong at the same time—including problems with the immune system, energy production in cells, hormone balance, and gut health. These problems appear to feed into each other, creating a cycle that keeps the illness going. The findings suggest ME/CFS is not just one thing breaking down, but rather many interconnected systems all struggling together.

Metabolic DysfunctionNeuroinflammationPost-Exertional MalaiseImmune Dysregulation
E1 ReplicatedPEM ✓Moderate confidenceReviewed

Cardiopulmonary exercise testing and post-exertional malaise in ME/CFS: A retrospective analysis

Staci R. Stevens, Christopher R. Snell, Jared N. Stevens et al.·Journal of Translational Medicine·2018·n=51

ME/CFS patients underwent two consecutive days of cardiopulmonary exercise testing (CPET). On the second day, patients showed significantly reduced VO2 max and anaerobic threshold compared to the first day — and compared to healthy and disease controls who recovered normally. This objective impairment matches the subjective PEM experience.

Post-Exertional MalaiseDiagnostics
E2 ModeratePEM ✓Higher confidenceReviewed

Incidence and Prevalence of Post-COVID-19 Myalgic Encephalomyelitis: A Report from the Observational RECOVER-Adult Study.

Vernon, Suzanne D, Zheng, Tianyu, Do, Hyungrok et al.·Journal of general internal medicine·2025

This study tracked over 11,000 people who had COVID-19 and about 1,400 who didn't, following them for at least 6 months to see how many developed ME/CFS. Researchers found that people who had COVID-19 were nearly 5 times more likely to develop ME/CFS compared to people who never had COVID-19. About 4.5% of COVID-infected participants developed ME/CFS, compared to only 0.6% of uninfected people.

Post-Exertional Malaise
E2 ModeratePEM ✓Moderate confidenceReviewed

Post-exertional malaise among people with long COVID compared to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).

Vernon, Suzanne D, Hartle, Megan, Sullivan, Karen et al.·Work (Reading, Mass.)·2023

This study looked at whether people with Long COVID experience post-exertional malaise (PEM)—a hallmark symptom of ME/CFS where symptoms get worse after physical or mental activity. Researchers surveyed 80 Long COVID patients and compared their experiences to 151 ME/CFS patients. Nearly all Long COVID patients reported having PEM, but the way they experienced it differed significantly from ME/CFS patients in terms of what triggered it, which symptoms appeared, and how to recover.

Post-Exertional Malaise
E2 ModeratePEM ✓PreliminaryReviewed

Post-exertional malaise in Long COVID: subjective reporting versus objective assessment.

Stussman, Barbara, Camarillo, Nathan, McCrossin, Gayle et al.·Frontiers in neurology·2025

This study looked at post-exertional malaise (PEM)—the symptom worsening that happens after activity—in people with Long COVID. Researchers asked patients about PEM symptoms and had some patients do an exercise test to see if PEM actually occurred. While 67% of patients reported having PEM symptoms, only 6% actually showed clear PEM after the exercise test. When PEM did occur in Long COVID, it was less severe than what the researchers saw in ME/CFS patients.

Post-Exertional Malaise
E2 ModeratePEM ✓Moderate confidenceReviewed

Deconstructing post-exertional malaise in myalgic encephalomyelitis/ chronic fatigue syndrome: A patient-centered, cross-sectional survey.

Chu, Lily, Valencia, Ian J, Garvert, Donn W et al.·PloS one·2018

This study asked 150 ME/CFS patients to describe what happens when they experience post-exertional malaise (PEM)—the characteristic crash that follows physical activity, mental effort, or emotional stress. Researchers found that 90% of patients experienced PEM from all three types of triggers, with fatigue being the most common symptom, but also cognitive problems, sleep issues, headaches, and muscle pain. Most patients' PEM lasted at least 24 hours, though the timing and severity varied from person to person.

Post-Exertional Malaise
E2 ModeratePEM ✓PreliminaryReviewed

Two symptoms can accurately identify post-exertional malaise in myalgic encephalomyelitis/chronic fatigue syndrome.

Davenport, Todd E, Chu, Lily, Stevens, Staci R et al.·Work (Reading, Mass.)·2023

This study found that asking patients about just two specific symptoms can accurately identify post-exertional malaise (PEM), the key feature of ME/CFS. Researchers had people with ME/CFS and healthy controls exercise twice, 24 hours apart, and report their symptoms at different times. The most reliable symptoms for identifying PEM were cognitive problems (brain fog), worsening function, and loss of positive feelings or mood.

Post-Exertional Malaise
E2 ModeratePEM ✓Moderate confidenceReviewed

Clinical Characteristics of Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Diagnosed in Patients with Long COVID.

Tokumasu, Kazuki, Honda, Hiroyuki, Sunada, Naruhiko et al.·Medicina (Kaunas, Lithuania)·2022

This study examined patients with long COVID who developed ME/CFS, a serious condition causing extreme fatigue and worsening after activity. Researchers found that about 17% of long COVID patients met standardized medical criteria for ME/CFS, with fatigue and post-exertional malaise being the most common symptoms. Interestingly, men and women were affected equally in this group, which differs from typical ME/CFS patterns.

Post-Exertional Malaise
E2 ModeratePEM ✓Moderate confidenceReviewed

Activity measurement in pediatric chronic fatigue syndrome.

Loiacono, Bernardo, Sunnquist, Madison, Nicholson, Laura et al.·Chronic illness·2022

This study compared how active children with ME/CFS are compared to healthy children. Researchers used activity tracking devices and asked children to report their own activity levels. Children with ME/CFS were less active overall and had unusual sleep-wake patterns, with more activity at night and delayed activity during the day. The good news is that children with ME/CFS could accurately report their own activity levels.

Post-Exertional Malaise
E2 ModeratePEM ✗Moderate confidenceReviewed

Replicated blood-based biomarkers for myalgic encephalomyelitis not explicable by inactivity.

Beentjes, Sjoerd Viktor, Miralles Méharon, Artur, Kaczmarczyk, Julia et al.·EMBO molecular medicine·2025

Researchers found multiple blood markers that distinguish ME/CFS patients from healthy people, including signs of inflammation, insulin problems, and liver issues. Importantly, these differences were NOT caused by patients being physically inactive—they are genuine biological changes related to the disease itself. While no single blood test can diagnose ME/CFS yet, these findings suggest that a combination of blood markers could eventually provide objective diagnosis.

Post-Exertional Malaise
E2 ModeratePEM ✓PreliminaryMachine draft

Pediatric Post-Acute Sequelae of SARS-CoV-2 Infection.

Jason, Leonard A, Johnson, Madeline, Torres, Chelsea·Fatigue : biomedicine, health & behavior·2023

This study compared young people recovering from long COVID (PASC) with young people who have ME/CFS to understand how their symptoms differ. Researchers asked 19 parents about their child's symptoms during initial COVID infection and again later, then compared these to 19 young people with ME/CFS. Most PASC symptoms improved over time, but fatigue and sleep problems stayed high—similar to what ME/CFS patients experience.

Sleep DysfunctionPost-Exertional Malaise
E2 ModeratePEM ✓Moderate confidenceMachine draft

ME/CFS and Post-Exertional Malaise among Patients with Long COVID.

Jason, Leonard A, Dorri, Joseph A·Neurology international·2022

Researchers studied 465 people with long-term COVID symptoms to see how many also had ME/CFS (a serious condition causing extreme fatigue and worsening after activity). They found that about 6 in 10 people with long COVID met the medical criteria for ME/CFS. Interestingly, some people thought they had ME/CFS when they didn't, while others had ME/CFS without realizing it—showing that self-diagnosis alone isn't reliable.

Long COVID OverlapPost-Exertional Malaise
E2 ModeratePEM ✓Moderate confidenceMachine draft

One-year follow-up of young people with ME/CFS following infectious mononucleosis by Epstein-Barr virus.

Pricoco, Rafael, Meidel, Paulina, Hofberger, Tim et al.·Frontiers in pediatrics·2023

This study followed 25 young people (12 teenagers and 13 young adults) who developed ME/CFS after having infectious mononucleosis caused by Epstein-Barr virus. Researchers checked on their symptoms and quality of life at the start, 6 months, and 12 months later. Teenagers showed better improvement over the year, with more than half no longer meeting ME/CFS criteria, while young adults continued to have severe symptoms with little improvement.

BiomarkersPost-Exertional Malaise
E2 ModeratePEM ✓Moderate confidenceMachine draft

Evaluating case diagnostic criteria for myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): toward an empirical case definition.

Conroy, Karl E, Islam, Mohammed F, Jason, Leonard A·Disability and rehabilitation·2023

This study looked at how doctors diagnose ME/CFS by analyzing symptoms reported by over 2,300 patients from around the world. Researchers used statistical methods to identify which symptoms tend to occur together, then compared their findings to three existing diagnostic guidelines. They found that the symptoms cluster into seven main groups, with post-exertional malaise (worsening after activity), cognitive problems, and sleep issues being particularly important.

Sleep DysfunctionPost-Exertional Malaise
E2 ModeratePEM ✓Moderate confidenceMachine draft

The Clinical Relevance of Mast Cell Activation in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Rohrhofer, Johanna, Ebner, Lilian, Schweighardt, Johannes et al.·Diagnostics (Basel, Switzerland)·2025

This study looked at whether mast cells—immune cells that release chemicals causing inflammation—play a role in ME/CFS. Researchers surveyed 687 ME/CFS patients and reviewed records from 383 others, finding that about 25% had signs of problematic mast cell activation. Importantly, patients with mast cell problems who received targeted treatment reported better symptom relief than those without mast cell involvement, suggesting this might be a treatable subtype of ME/CFS.

Post-Exertional MalaiseImmune Dysregulation
E2 ModeratePEM ✗PreliminaryMachine draft

Characterizing Sjögren-Associated Fatigue: A Distinct Phenotype from ME/CFS.

Kim, Laura, Kedor, Claudia, Buttgereit, Frank et al.·Journal of clinical medicine·2023

This study compared fatigue in people with Sjögren's syndrome (an autoimmune disease affecting moisture-producing glands) to fatigue in ME/CFS patients. While both groups experience severe tiredness, the researchers found important differences: Sjögren's patients recovered their muscle strength within an hour of activity, whereas ME/CFS patients typically experience worsening symptoms hours after exertion. Only a small portion of Sjögren's patients met ME/CFS diagnostic criteria, suggesting these are distinct conditions despite some symptom overlap.

Post-Exertional Malaise
E2 ModeratePEM ✓Moderate confidenceMachine draft

Prevalence of myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) in Australian primary care patients: only part of the story?

Orji, Nneka, Campbell, Julie A, Wills, Karen et al.·BMC public health·2022

This study looked at how many people in Australia have ME/CFS by examining medical records from primary care clinics between 2015-2019. Researchers found that roughly 95-104 people per 100,000 have ME/CFS in Australia, but they also discovered that many patients avoid visiting their doctors because of stigma, disbelief in the condition, and lack of available treatments. The researchers concluded that the real number of people with ME/CFS is likely much higher than what their numbers show.

Post-Exertional Malaise
E2 ModeratePEM ✓Moderate confidenceMachine draft

A Brief Questionnaire to Assess Post-Exertional Malaise.

Cotler, Joseph, Holtzman, Carly, Dudun, Catherine et al.·Diagnostics (Basel, Switzerland)·2018

This study focused on creating a better way to identify post-exertional malaise (PEM)—the worsening of symptoms that happens after physical or mental activity in ME/CFS patients. Researchers tested whether five additional questions from an existing questionnaire could help doctors confirm PEM in the second step of diagnosis. The test was successful: it correctly identified patients with ME/CFS 82% of the time and rarely misidentified other conditions like multiple sclerosis as ME/CFS.

Post-Exertional Malaise
E2 ModeratePEM ✓PreliminaryMachine draft

Unravelling myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS): Gender-specific changes in the microRNA expression profiling in ME/CFS.

Cheema, Amanpreet K, Sarria, Leonor, Bekheit, Mina et al.·Journal of cellular and molecular medicine·2020

This study looked at tiny molecules called microRNAs in the blood of people with ME/CFS to understand how their immune system responds to exercise. The researchers discovered that men and women with ME/CFS show different patterns in these molecules, and they also found that nutritional status affects these patterns. These findings could help explain why some people experience worsening symptoms after exercise (post-exertional malaise) and suggest that treatment approaches may need to differ between men and women.

Post-Exertional MalaiseImmune Dysregulation
E2 ModeratePEM ✓Moderate confidenceMachine draft

Recovery from Exercise in Persons with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

Moore, Geoffrey E, Keller, Betsy A, Stevens, Jared et al.·Medicina (Kaunas, Lithuania)·2023

This study measured how long it takes people with ME/CFS to recover after exercise compared to healthy people. Researchers gave participants two exercise tests on consecutive days and tracked their symptoms for 10 days afterward. People with ME/CFS took an average of about 2 weeks to recover, while healthy controls recovered in just 2 days—showing that post-exertional malaise (the characteristic symptom flare after activity) lasts much longer in ME/CFS.

Post-Exertional Malaise
E2 ModeratePEM ✓Moderate confidenceMachine draft

Post-exertional symptoms distinguish Myalgic Encephalomyelitis/Chronic Fatigue Syndrome subjects from healthy controls.

Mateo, Lariel J, Chu, Lily, Stevens, Staci et al.·Work (Reading, Mass.)·2020

This study looked at how ME/CFS patients and healthy people felt after doing a hard exercise test. ME/CFS patients experienced many more symptoms afterward—an average of 14 different types—compared to healthy people who reported only 4. Importantly, ME/CFS patients continued having symptoms for up to a week after exercise, while healthy controls had none. The most common symptoms were fatigue, brain fog, and sleep problems.

Post-Exertional Malaise
E3 PreliminaryPEM ?Moderate confidenceReviewed

Mitochondrial Dysfunction in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Syed, Abu Mohammad, Karius, Alexander K, Ma, Jin et al.·Physiology (Bethesda, Md.)·2025

This review examines how mitochondria—the parts of cells that produce energy—may not be working properly in ME/CFS patients. The authors suggest that problems with energy production in cells could explain why people with ME/CFS feel severely exhausted after physical activity. They also note that similar energy problems appear in long COVID, which suggests both conditions may share a common underlying cause.

Long COVID OverlapPost-Exertional Malaise
E3 PreliminaryPEM ✓PreliminaryReviewed

Single-cell transcriptomics of the immune system in ME/CFS at baseline and following symptom provocation.

Vu, Luyen Tien, Ahmed, Faraz, Zhu, Hongya et al.·Cell reports. Medicine·2024

Researchers used advanced technology to examine immune cells from ME/CFS patients and healthy controls, both at rest and after exercise. They found that ME/CFS patients have problems with a type of immune cell called monocytes that appear abnormal and may be moving into tissues inappropriately. After exercise, patients showed additional problems with platelets (cells involved in blood clotting), suggesting the disease involves multiple layers of immune system dysfunction.

Post-Exertional MalaiseImmune Dysregulation
E3 PreliminaryPEM ✓Moderate confidenceReviewed

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS): An Overview.

Deumer, Undine-Sophie, Varesi, Angelica, Floris, Valentina et al.·Journal of clinical medicine·2021

ME/CFS is a long-term illness that causes extreme tiredness, worsening of symptoms after activity, and difficulty thinking clearly. Patients experience these symptoms very differently from one another, and currently there are no blood tests or physical exams that can definitively diagnose the condition. This review examines several potential causes, including past infections, genetic factors, hormone imbalances, and changes in gut bacteria, while exploring whether a simple blood test might someday help diagnose ME/CFS.

BiomarkersPost-Exertional Malaise
E3 PreliminaryPEM ✓PreliminaryReviewed

Attenuating post-exertional malaise in Myalgic encephalomyelitis/chronic fatigue syndrome and long-COVID: Is blood lactate monitoring the answer?

Faghy, Professor Mark A, Ashton, Dr Ruth Em, McNelis, Mr Robin et al.·Current problems in cardiology·2024

This editorial discusses whether measuring blood lactate levels could help manage post-exertional malaise (PEM)—the debilitating fatigue that occurs after physical activity in ME/CFS and long-COVID patients. The authors suggest that blood lactate monitoring might help identify safe exercise limits and prevent PEM crashes. However, this is an opinion piece rather than a research study with new data.

BiomarkersPost-Exertional Malaise
E3 PreliminaryPEM ✓PreliminaryReviewed

Review of the Midbrain Ascending Arousal Network Nuclei and Implications for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS), Gulf War Illness (GWI) and Postexertional Malaise (PEM).

Baraniuk, James N·Brain sciences·2022

This review examines a brain region called the midbrain and how it might contribute to post-exertional malaise (PEM)—the worsening of symptoms after activity that happens in ME/CFS. When ME/CFS patients did exercise in a study, their midbrain showed increased activity during mental tasks, while Gulf War Illness patients showed the opposite pattern. The authors suggest that problems in this brain region could explain why ME/CFS patients have trouble with energy, sleep, mood, pain, and temperature control, especially after exertion.

Cognitive ImpairmentPost-Exertional Malaise
E3 PreliminaryPEM ✓Moderate confidenceReviewed

Chronic Fatigue Syndrome/Myalgic Encephalomyelitis (CFS/ME) in Adolescents: Practical Guidance and Management Challenges.

Rowe, Katherine·Adolescent health, medicine and therapeutics·2023

ME/CFS is a serious illness causing extreme tiredness that doesn't improve with rest, along with worsening after activity, brain fog, poor sleep, and sometimes dizziness and pain. This paper reviews what we know about treating ME/CFS in teenagers and young people, finding that currently there are no proven cure treatments, but symptom management and lifestyle adjustments help most. The study emphasizes that staying connected to school and having supportive doctors who listen made the biggest difference in how well young people managed their illness over time.

Post-Exertional Malaise
E3 PreliminaryPEM ✓PreliminaryReviewed

Tetrahydrobiopterin in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: A Friend or Foe?

Rahman, A F M Towheedur, Benko, Anna, Bulbule, Sarojini et al.·Biomolecules·2025

This review article examines a molecule called tetrahydrobiopterin (BH4) and its possible role in ME/CFS, particularly in patients who experience orthostatic intolerance (dizziness or fainting when standing up). The researchers found that BH4 metabolism—the way the body processes this molecule—is not working properly in ME/CFS patients with these symptoms. By understanding how BH4 goes wrong, scientists hope to explain why ME/CFS patients have problems with blood flow to the brain.

BiomarkersPost-Exertional Malaise
E3 PreliminaryPEM ✓Moderate confidenceReviewed

Documenting disability in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS).

Podell, Richard, Dimmock, Mary E, Comerford, Barbara B·Work (Reading, Mass.)·2020

This article helps doctors and lawyers understand how to properly document ME/CFS for disability benefits. The authors reviewed successful disability cases and identified the best ways to prove that ME/CFS prevents someone from working, including showing how post-exertional malaise (getting much worse after activity) impacts daily life. The goal is to help more ME/CFS patients access the disability benefits they need and deserve.

Post-Exertional Malaise
E3 PreliminaryPEM ✓PreliminaryReviewed

Heightened innate immunity may trigger chronic inflammation, fatigue and post-exertional malaise in ME/CFS.

Che, Xiaoyu, Ranjan, Amit, Guo, Cheng et al.·medRxiv : the preprint server for health sciences·2025

This study found that people with ME/CFS may have an overactive immune system that responds too strongly to germs and infections. The research showed problems with how the body produces energy and manages inflammation, and these problems got worse after exercise in ME/CFS patients but not in healthy people. The findings suggest multiple biological systems are working abnormally in ME/CFS, which could help doctors develop better treatments.

Metabolic DysfunctionPost-Exertional MalaiseImmune Dysregulation
E3 PreliminaryPEM ✓PreliminaryReviewed

Heightened innate immunity may trigger chronic inflammation, fatigue and post-exertional malaise in ME/CFS.

Che, Xiaoyu, Ranjan, Amit, Guo, Cheng et al.·npj metabolic health and disease·2025

This study examined blood samples and immune responses in ME/CFS patients to understand why they experience extreme fatigue and feeling worse after activity. Researchers found that patients' immune systems overreact to germs, their bodies have trouble producing energy efficiently, and they have several chemical imbalances in their blood. These problems got worse after exercise and matched how sick patients felt.

Metabolic DysfunctionPost-Exertional MalaiseImmune Dysregulation
E3 PreliminaryPEM ✓PreliminaryReviewed

Dissecting the genetic complexity of myalgic encephalomyelitis/chronic fatigue syndrome via deep learning-powered genome analysis.

Zhang, Sai, Jahanbani, Fereshteh, Chander, Varuna et al.·medRxiv : the preprint server for health sciences·2025

Researchers used advanced artificial intelligence to analyze the genes of ME/CFS patients and discovered 115 genes that may contribute to the disease. They found that people with ME/CFS have lower levels of these risk genes active in their immune cells and nervous system. This genetic analysis could eventually help doctors diagnose ME/CFS more accurately and identify new treatment targets.

BiomarkersCognitive ImpairmentPost-Exertional MalaiseImmune Dysregulation
E3 PreliminaryPEM ✓PreliminaryReviewed

Precision Medicine Study of Post-Exertional Malaise Epigenetic Changes in Myalgic Encephalomyelitis/Chronic Fatigue Patients During Exercise.

Sharma, Sayan, Hodges, Lynette D, Peppercorn, Katie et al.·International journal of molecular sciences·2025

This study looked at how exercise affects the chemical switches on our genes (epigenetics) in ME/CFS patients, particularly during post-exertional malaise (PEM)—the exhaustion that worsens after physical activity. Researchers took blood samples from five ME/CFS patients before, immediately after, and 24-48 hours after an exercise test, and found distinct patterns of genetic changes that were specific to ME/CFS patients and not seen in healthy controls. These changes affected genes related to immune function, inflammation, and blood vessel health, suggesting the body's response to exercise in ME/CFS is fundamentally different at the molecular level.

BiomarkersPost-Exertional MalaiseImmune Dysregulation
E3 PreliminaryPEM ✓PreliminaryReviewed

Problems in defining post-exertional malaise.

Jason, Leonard A, Evans, Meredyth, So, Suzanna et al.·Journal of prevention & intervention in the community·2015

This study looked at how post-exertional malaise (PEM)—the characteristic worsening of symptoms after physical or mental effort—is measured in ME/CFS patients. Researchers asked 32 people with CFS to answer survey questions about PEM and found that small changes in how questions are worded can change whether someone is diagnosed with PEM. This suggests that the current ways of diagnosing this condition may not be reliable or consistent.

Post-Exertional Malaise
E3 PreliminaryPEM ✓PreliminaryReviewed

COVID-19 and post-infectious myalgic encephalomyelitis/chronic fatigue syndrome: a narrative review.

Poenaru, Sonia, Abdallah, Sara J, Corrales-Medina, Vicente et al.·Therapeutic advances in infectious disease·2021

Some people who recover from COVID-19 continue experiencing prolonged symptoms like fatigue, difficulty breathing, and brain fog for months afterward. These lingering symptoms are remarkably similar to ME/CFS, a chronic illness characterized by severe fatigue that worsens with activity. While COVID-19 could potentially trigger ME/CFS in some people, researchers currently don't have enough evidence to confirm this connection.

Post-Exertional Malaise
E3 PreliminaryPEM ✓Moderate confidenceReviewed

[Post-COVID syndrome with fatigue and exercise intolerance: myalgic encephalomyelitis/chronic fatigue syndrome].

Renz-Polster, Herbert, Scheibenbogen, Carmen·Innere Medizin (Heidelberg, Germany)·2022

This article explains that ME/CFS is a serious neurological and immune system disease, often triggered by infections like COVID-19, characterized by extreme fatigue lasting at least 6 months and a unique symptom called post-exertional malaise (PEM)—where even mild activity causes symptoms to worsen hours or days later. The authors stress that ME/CFS is a distinct medical condition that should not be confused with ordinary tiredness, and while there is no cure yet, treatment focuses on managing symptoms, addressing related circulation problems, and helping patients conserve energy through pacing.

Post-Exertional Malaise
E3 PreliminaryPEM ✗Weak / uncertainReviewed

An Overview of Severe Myalgic Encephalomyelitis.

Vink, Mark, Vink-Niese, Alexandra·Journal of clinical medicine·2026

This article reviews what we know about severe ME/CFS, a serious illness that can leave people completely bedbound and dependent on caregivers. Currently, there is no blood test or scan that can diagnose ME/CFS, though a special two-day exercise test can help document the problem. The authors emphasize that severe ME/CFS is a major medical condition that has received very little research funding, and there are currently no proven treatments available.

Post-Exertional Malaise
E3 PreliminaryPEM ✓PreliminaryMachine draft

Exertional Exhaustion (Post-Exertional Malaise, PEM) Evaluated by the Effects of Exercise on Cerebrospinal Fluid Metabolomics-Lipidomics and Serine Pathway in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Baraniuk, James N·International journal of molecular sciences·2025

This study examined fluid from around the brain and spinal cord in ME/CFS patients and healthy controls, measuring chemical substances before and after exercise. Researchers found that ME/CFS patients have abnormal levels of certain chemicals related to energy production and brain function, especially after exercise. The study suggests that exercise may trigger harmful changes in brain chemistry in ME/CFS patients that don't happen in healthy people, which could explain post-exertional malaise (the worsening of symptoms after activity).

Post-Exertional Malaise
E3 PreliminaryPEM ✓PreliminaryMachine draft

Post-exertional malaise in daily life and experimental exercise models in patients with myalgic encephalomyelitis/chronic fatigue syndrome.

Vøllestad, Nina K, Mengshoel, Anne Marit·Frontiers in physiology·2023

This paper reviews how post-exertional malaise (PEM)—the worsening of symptoms after physical or mental activity—is experienced and studied in ME/CFS patients. Patients describe PEM in many different ways and report that it can start immediately or be delayed by days, lasting anywhere from a few days to months. When researchers use standardized exercise tests in laboratories, they see more immediate symptom worsening, but the duration still varies widely between patients.

Autonomic Nervous SystemPost-Exertional Malaise
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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.

Post-Exertional Malaise
E3 PreliminaryPEM ✓Moderate confidenceMachine draft

Medically Documenting Disability in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) Cases.

Comerford, Barbara B, Podell, Richard·Frontiers in pediatrics·2019

This guideline addresses how doctors can properly document ME/CFS symptoms to support disability claims, especially for children and teens. Many ME/CFS patients see doctors unfamiliar with the condition, which can lead to misdiagnosis and rejected disability applications. The guideline emphasizes that ME/CFS is a real physical illness affecting multiple body systems, not a psychological condition.

Post-Exertional Malaise
E3 PreliminaryPEM ✓PreliminaryMachine draft

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.

Post-Exertional MalaiseImmune Dysregulation
E3 PreliminaryPEM ✓Weak / uncertainMachine draft

[Facts and myths about chronic fatigue syndrome].

Fink, Per, Skjernov, Mathias, Petersen, Line Kirkeby et al.·Ugeskrift for laeger·2022

This article discusses updates to ME/CFS treatment guidelines and challenges some common beliefs about the condition. The authors argue that new guidelines recommend against intense exercise programs for severely ill patients and suggest energy management instead, but they question whether the evidence supporting these changes was properly evaluated. They raise concerns about how the new guidelines were developed and what type of evidence was considered.

Post-Exertional Malaise
E3 PreliminaryPEM ✓Moderate confidenceMachine draft

Expert perspectives on Myalgic encephalomyelitis/chronic fatigue syndrome - Insights from the 3rd International Conference of the Charité Fatigue Center.

Fehrer, Annick, Windzio, Lara, Schoening, Simon et al.·Autoimmunity reviews·2026

Nearly 4,000 ME/CFS researchers and experts gathered at an international conference in May 2025 to share the latest discoveries about this serious illness. They discussed how ME/CFS develops, better ways to diagnose it, and new treatments being tested. The conference highlighted that while COVID-19 has brought more attention and funding to ME/CFS research, the disease is still not well understood and needs much more study.

Metabolic DysfunctionPost-Exertional MalaiseImmune Dysregulation