ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

1–20 of 355 studies

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E0 ConsensusReviewPEM unclearSystematic-Review

Association between myalgic encephalomyelitis/chronic fatigue syndrome and irritable bowel syndrome: a systematic review and meta-analysis.

Rajabi, Natalie, Ramdass, Prakash V A K·Frontiers in medicine·2026

A new systematic review combined data from 22 studies to examine how often irritable bowel syndrome (IBS) and ME/CFS occur together. Researchers reported that people with ME/CFS were substantially more likely to also have IBS compared to people without ME/CFS, and that about 37% of people with ME/CFS in these studies had IBS. However, the results varied considerably depending on which diagnostic criteria were used to define ME/CFS, suggesting uncertainty about the true overlap.

Gut MicrobiomeAutonomic Nervous SystemDiagnosticsImmune System

E0 ConsensusReviewPEM not requiredMeta-Analysis

Risks of autoimmune and inflammatory post-acute COVID-19 conditions: a network cohort study in six European countries, the USA and Korea.

Burkard, Theresa Ms, López-Güell, Kim, Català, Martí et al.·BMJ public health·2026

This large study looked at whether people who had COVID-19 were more likely to develop autoimmune or inflammatory conditions—including ME/CFS and POTS—in the 9 months after infection. Researchers examined health records from over 2.5 million people across eight countries and did not observe increased rates of these conditions in COVID-19 patients compared to people who tested negative. However, the findings do not yet tell us whether similar patterns apply to ME/CFS specifically, and the study was observational rather than experimental.

Autonomic Nervous SystemImmune SystemLong COVID Overlap

E0 ConsensusReviewPEM unclearReview-Narrative

[Post-COVID: An inventory focusing on the key complaints PEM and POTS].

Hensel, Ole, Pfrommer, Laura, Furch, Peggy et al.·MMW Fortschritte der Medizin·2026

This is a narrative review (a summary of existing research rather than a new study) that examined long-term effects of COVID-19, with a focus on post-exertional malaise (PEM) and postural tachycardia syndrome (POTS). The authors report that in people with post-COVID, PEM—a worsening of symptoms after exertion—was observed in approximately 86% of patients, and POTS-related symptoms in up to 82%. The review suggests pacing and symptom-focused treatments may help, though these are early findings from a narrative synthesis rather than definitive evidence.

InterventionsAutonomic Nervous SystemDiagnosticsLong COVID Overlap

E0 ConsensusReviewPEM unclearReview-Narrative

Physiotherapy management of Long-COVID: an evidence-based approach.

Reeves, Jack, Daynes, Enya, Janaudis-Ferreira, Tania et al.·Brazilian journal of physical therapy·2026

This guideline describes how physiotherapists can manage Long-COVID using evidence-based approaches. The recommendations include assessment of fatigue, post-exertional malaise, breathing problems, cognitive symptoms, and orthostatic intolerance, followed by tailored management such as pacing, energy conservation, breathing retraining, and return-to-work planning. The authors emphasise the importance of validating patient experiences and individualising care, though the evidence base for these specific approaches in Long-COVID remains under development.

InterventionsAutonomic Nervous SystemCognitive ImpairmentPost-Exertional Malaise

E0 ConsensusReviewPEM unclearSystematic-Review

Systematic literature review: treatment of postural orthostatic tachycardia syndrome (POTS).

Schiweck, Nicole, Langer, Katharina, Maier, Andrea et al.·Clinical autonomic research : official journal of the Clinical Autonomic Research Society·2026

This review examined treatments for POTS (postural orthostatic tachycardia syndrome), a condition where your heart rate jumps significantly when you stand up, causing dizziness and fatigue. POTS is common in people with ME/CFS. The researchers looked at 45 studies and found that simple first-line treatments like compression socks, physical training, extra salt, and a vagus nerve stimulation device may help, while certain medications like ivabradine and beta-blockers also showed promise in some studies.

Autonomic Nervous System

E0 ConsensusReviewPEM unclearSystematic-Review

Decreased Heart Rate Variability Is Associated with Increased Fatigue Across Different Medical Populations: A Systematic Review.

Penfold, Sophie Maria, Cunningham, James, Whelan, Pauline et al.·Pathophysiology : the official journal of the International Society for Pathophysiology·2025

This review looked at 17 studies examining the link between fatigue and heart rate variability (HRV)—a measure of how well your nervous system is working. The researchers found that people who feel more fatigued tend to have imbalanced heart rate patterns, suggesting their autonomic nervous system (the part controlling automatic body functions) may not be working properly. ME/CFS patients were the most studied group, making this particularly relevant to understanding fatigue in this condition.

Autonomic Nervous System

E0 ConsensusReviewPEM unclearSystematic-Review

Systematic review: digital biomarkers of fatigue in chronic diseases.

Aboagye, Nana Yaw, Hinchliffe, Chloe, Del Din, Silvia et al.·NPJ digital medicine·2025

This review looked at studies using wearable devices (like fitness trackers) to measure fatigue in people with various chronic illnesses, including ME/CFS. Researchers found that across many diseases, reduced physical activity, more sitting time, and problems with the body's automatic nervous system (which controls heart rate and breathing) were linked to higher fatigue levels. The findings suggest that wearable devices might help doctors personalize fatigue management for individual patients.

Autonomic Nervous System

E0 ConsensusReviewPEM unclear

Mapping cerebral blood flow in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and orthostatic intolerance: insights from a systematic review.

Christopoulos, Elena M, Tantanis, Darcy, Huang, Katherine et al.·Journal of translational medicine·2025

This review examined 118 research studies to understand how blood flow to the brain changes in ME/CFS patients, particularly those who also experience orthostatic intolerance (difficulty maintaining blood pressure when standing). Researchers found that blood flow to the brain is often reduced in both conditions, and when patients have both ME/CFS and orthostatic intolerance together, the reduction in brain blood flow appears to be even more pronounced. This finding suggests that measuring brain blood flow might help doctors track how severe the disease is.

Autonomic Nervous System

E0 ConsensusReviewPEM not requiredReview-Narrative

Autoimmune Autonomic Neuropathy: From Pathogenesis to Diagnosis.

Nakane, Shunya, Koike, Haruki, Hayashi, Tomohiro et al.·International journal of molecular sciences·2024

This review describes autoimmune autonomic ganglionopathy (AAG), a rare condition where the immune system attacks nerve cells that control automatic body functions like heart rate and blood pressure. The authors explain how doctors can diagnose AAG and how it differs from other similar conditions, including ME/CFS and long COVID, which can have overlapping symptoms.

Autonomic Nervous SystemDiagnostics

E0 ConsensusReviewPEM unclearMeta-Analysis

Objective sleep measures in chronic fatigue syndrome patients: A systematic review and meta-analysis.

Mohamed, Abdalla Z, Andersen, Thu, Radovic, Sanja et al.·Sleep medicine reviews·2023

This study looked at 24 research papers that measured sleep objectively (using devices and tests, not just patient reports) in people with ME/CFS. The researchers found that ME/CFS patients do indeed have real, measurable sleep problems—they take longer to fall asleep, wake up more during the night, and don't get good-quality sleep. Interestingly, these sleep problems looked slightly different in teenagers compared to adults with ME/CFS.

SleepAutonomic Nervous System

E0 ConsensusReviewPEM unclearEditorial

Understanding, diagnosing, and treating Myalgic encephalomyelitis/chronic fatigue syndrome - State of the art: Report of the 2nd international meeting at the Charité Fatigue Center.

Steiner, Sophie, Fehrer, Annick, Hoheisel, Friederike et al.·Autoimmunity reviews·2023

Over 100 international researchers gathered in Berlin in May 2023 to discuss what we currently know about ME/CFS, how to diagnose it, and how to treat it. The conference highlighted that ME/CFS involves problems with the immune system, blood vessel function, and nervous system control, and that some cases may be triggered by viruses reactivating in the body. Despite growing interest due to Long COVID, ME/CFS remains under-researched and needs significantly more funding to find better diagnostic tests and targeted treatments.

Autonomic Nervous SystemImmune System

E0 ConsensusReviewPEM not requiredReview-Narrative

Autoimmune autonomic nervous system imbalance and conditions: Chronic fatigue syndrome, fibromyalgia, silicone breast implants, COVID and post-COVID syndrome, sick building syndrome, post-orthostatic tachycardia syndrome, autoimmune diseases and autoimmune/inflammatory syndrome induced by adjuvants.

Malkova, A M, Shoenfeld, Y·Autoimmunity reviews·2023

This review examined whether ME/CFS, fibromyalgia, and several other conditions share a common problem: the immune system mistakenly attacks nerve controls that regulate heart rate, blood pressure, and other automatic body functions. Researchers found that people with these conditions often have similar symptoms like fatigue, dizziness, and brain fog, and some have autoantibodies (immune proteins) that target nerve receptors. The authors propose this 'autonomic nervous system imbalance' could be a unifying mechanism explaining why these diverse conditions feel so similar.

Autonomic Nervous System

E0 ConsensusReviewPEM not requiredMeta-Analysis

Reduced Heart Rate Variability in Patients With Medically Unexplained Physical Symptoms: A Meta-Analysis of HF-HRV and RMSSD.

Vreijling, Sarah R, Troudart, Yael, Brosschot, Jos F·Psychosomatic medicine·2021

This study looked at heart rate variability (how much your heart rate changes moment-to-moment) in people with chronic fatigue syndrome, irritable bowel syndrome, and fibromyalgia. Researchers combined results from 58 previous studies and found that patients with these conditions had lower heart rate variability than healthy people, suggesting their nervous systems may not be regulating heart rate as flexibly as they should.

Autonomic Nervous System

E0 ConsensusReviewPEM not requiredMeta-Analysis

Heart rate variability in patients with somatic symptom disorders and functional somatic syndromes: A systematic review and meta-analysis.

Ying-Chih, Cheng, Yu-Chen, Huang, Wei-Lieh, Huang·Neuroscience and biobehavioral reviews·2020

This large review combined results from 85 studies comparing heart rhythm patterns between people with conditions like fibromyalgia and ME/CFS (functional somatic syndromes) and healthy people. Researchers found that patients with these conditions have lower heart rate variability—meaning their heart's rhythm is less flexible and adaptive—which suggests their nervous system may not be responding normally to stress and daily activities.

Autonomic Nervous System

E0 ConsensusReviewPEM unclearSystematic-Review

A systematic review of neurological impairments in myalgic encephalomyelitis/ chronic fatigue syndrome using neuroimaging techniques.

Maksoud, Rebekah, du Preez, Stanley, Eaton-Fitch, Natalie et al.·PloS one·2020

This review examined 55 studies that used brain imaging techniques to look for physical differences in the brains of people with ME/CFS compared to healthy people. The researchers found evidence that ME/CFS affects how the nervous system works, including changes in brain structure and blood flow. However, the findings weren't consistent across all studies, meaning scientists still don't have a complete picture of what's happening in the brain.

Autonomic Nervous SystemCognitive Impairment

E0 ConsensusReviewPEM unclearMeta-Analysis

Evidence of altered cardiac autonomic regulation in myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review and meta-analysis.

Nelson, Maximillian J, Bahl, Jasvir S, Buckley, Jonathan D et al.·Medicine·2019

This study looked at how the hearts of people with ME/CFS respond differently compared to healthy people, focusing on heart rate and its patterns. Researchers reviewed 64 previous studies and found that ME/CFS patients tend to have higher resting heart rates, unusual heart rate responses to position changes, and different patterns in heart rate variability (the natural variation in time between heartbeats). These findings suggest that the nervous system that controls heart function may work differently in people with ME/CFS.

Autonomic Nervous System

E0 ConsensusReviewPEM not requiredSystematic-Review

Postural tachycardia syndrome and other forms of orthostatic intolerance in Ehlers-Danlos syndrome.

Roma, Maria, Marden, Colleen L, De Wandele, Inge et al.·Autonomic neuroscience : basic & clinical·2018

This review looked at research connecting two conditions: orthostatic intolerance (difficulty standing up without dizziness, rapid heartbeat, or fainting) and Ehlers-Danlos syndrome (a connective tissue disorder causing loose joints and flexible skin). The researchers found that people with Ehlers-Danlos syndrome experience orthostatic intolerance symptoms much more often than healthy people, and these symptoms significantly affect their quality of life.

Autonomic Nervous System

E0 ConsensusReviewPEM not requiredReview-Narrative

Cognitive Dysfunction in Chronic Fatigue Syndrome: a Review of Recent Evidence.

Cvejic, Erin, Birch, Rachael C, Vollmer-Conna, Uté·Current rheumatology reports·2016

People with ME/CFS commonly experience 'brain fog'—problems with memory, attention, and concentration. While these cognitive problems are real and significantly impact daily life, the exact biological causes remain unclear. This review suggests that problems with blood flow to the brain and nervous system dysfunction may be involved, and calls for standardized testing methods to better understand what's happening.

Autonomic Nervous System

E0 ConsensusReviewPEM not requiredSystematic-Review

Sympathetic nervous system dysfunction in fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, and interstitial cystitis: a review of case-control studies.

Martínez-Martínez, Laura-Aline, Mora, Tania, Vargas, Angélica et al.·Journal of clinical rheumatology : practical reports on rheumatic & musculoskeletal diseases·2014

This review examined whether ME/CFS, fibromyalgia, IBS, and interstitial cystitis share a common problem: an overactive stress-response system in the nervous system. Researchers looked at 196 published studies that compared patients with these conditions to healthy controls. They found that about 65% of studies showed these patients have a nervous system stuck in 'overdrive,' which could explain why these conditions often occur together.

Autonomic Nervous System

E0 ConsensusReviewPEM not requiredSystematic-Review

Malfunctioning of the autonomic nervous system in patients with chronic fatigue syndrome: a systematic literature review.

Van Cauwenbergh, Deborah, Nijs, Jo, Kos, Daphne et al.·European journal of clinical investigation·2014

This review examined 27 studies that looked at how the autonomic nervous system (the part of your nervous system that controls automatic body functions like heart rate) works differently in ME/CFS patients compared to healthy people. Researchers found that ME/CFS patients often show unusual heart rate responses during tilting tests, which is consistent with a condition called postural orthostatic tachycardia syndrome (POTS). These autonomic nervous system differences might help doctors diagnose ME/CFS.

Autonomic Nervous System

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Evidence browser

Association between myalgic encephalomyelitis/chronic fatigue syndrome and irritable bowel syndrome: a systematic review and meta-analysis.

Risks of autoimmune and inflammatory post-acute COVID-19 conditions: a network cohort study in six European countries, the USA and Korea.

[Post-COVID: An inventory focusing on the key complaints PEM and POTS].

Physiotherapy management of Long-COVID: an evidence-based approach.

Systematic literature review: treatment of postural orthostatic tachycardia syndrome (POTS).

Decreased Heart Rate Variability Is Associated with Increased Fatigue Across Different Medical Populations: A Systematic Review.

Systematic review: digital biomarkers of fatigue in chronic diseases.

Mapping cerebral blood flow in myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) and orthostatic intolerance: insights from a systematic review.

Autoimmune Autonomic Neuropathy: From Pathogenesis to Diagnosis.

Objective sleep measures in chronic fatigue syndrome patients: A systematic review and meta-analysis.

Understanding, diagnosing, and treating Myalgic encephalomyelitis/chronic fatigue syndrome - State of the art: Report of the 2nd international meeting at the Charité Fatigue Center.

Autoimmune autonomic nervous system imbalance and conditions: Chronic fatigue syndrome, fibromyalgia, silicone breast implants, COVID and post-COVID syndrome, sick building syndrome, post-orthostatic tachycardia syndrome, autoimmune diseases and autoimmune/inflammatory syndrome induced by adjuvants.

Reduced Heart Rate Variability in Patients With Medically Unexplained Physical Symptoms: A Meta-Analysis of HF-HRV and RMSSD.

Heart rate variability in patients with somatic symptom disorders and functional somatic syndromes: A systematic review and meta-analysis.

A systematic review of neurological impairments in myalgic encephalomyelitis/ chronic fatigue syndrome using neuroimaging techniques.

Evidence of altered cardiac autonomic regulation in myalgic encephalomyelitis/chronic fatigue syndrome: A systematic review and meta-analysis.

Postural tachycardia syndrome and other forms of orthostatic intolerance in Ehlers-Danlos syndrome.

Cognitive Dysfunction in Chronic Fatigue Syndrome: a Review of Recent Evidence.

Sympathetic nervous system dysfunction in fibromyalgia, chronic fatigue syndrome, irritable bowel syndrome, and interstitial cystitis: a review of case-control studies.

Malfunctioning of the autonomic nervous system in patients with chronic fatigue syndrome: a systematic literature review.

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