Evidence browser

Sex differences in post-exercise fatigue and function in myalgic encephalomyelitis/chronic fatigue syndrome.

Friedberg, Fred, Adamowicz, Jenna L, Bruckenthal, Patricia et al.·Scientific reports·2023

This study looked at how men and women with ME/CFS respond differently to a simple exercise test (a six-minute walk). Researchers tracked fatigue levels and heart function for 15 days in 37 ME/CFS patients and 14 healthy people. Women with ME/CFS felt more tired after the first walk test, while men reported fewer work limitations in the days after exercise. Surprisingly, the study did not find the expected differences between men and women in how long it took to recover.

E2 ModerateCohortPEM unclearCross-Sectional

Skin Temperature Circadian Rhythms and Dysautonomia in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome: The Role of Endothelin-1 in the Vascular Tone Dysregulation.

Cambras, Trinitat, Zerón-Rugerio, Maria Fernanda, Díez-Noguera, Antoni et al.·International journal of molecular sciences·2023

This study looked at how the bodies of people with ME/CFS respond to position changes and whether problems with their blood vessel function might be involved. Researchers compared 67 women with ME/CFS to 48 healthy women, measuring their blood pressure, heart rate, body temperature patterns, and blood markers related to blood vessel health. They found that people with ME/CFS had higher blood pressure and heart rate, disrupted daily temperature rhythms, and elevated levels of substances in the blood that suggest blood vessel problems.

Autonomic Nervous System

Orthostatic Intolerance and Chronotropic Incompetence in Patients With Myalgic Encephalomyelitis or Chronic Fatigue Syndrome.

Miwa, Kunihisa·Circulation reports·2023

This study looked at how the hearts of ME/CFS patients respond when standing up. Researchers found that some patients have difficulty increasing their heart rate enough during standing, even when they don't experience the rapid heartbeat (POTS) that others with ME/CFS develop. For these patients, the ability to stand longer seemed to depend on having that rapid heartbeat response, suggesting their bodies may not be activating the right nervous system pathways to maintain blood pressure.

Autonomic Nervous System

E2 ModerateCohortPEM not requiredCross-Sectional

Chronic Fatigue, Depression and Anxiety Symptoms in Long COVID Are Strongly Predicted by Neuroimmune and Neuro-Oxidative Pathways Which Are Caused by the Inflammation during Acute Infection.

Al-Hakeim, Hussein Kadhem, Al-Rubaye, Haneen Tahseen, Almulla, Abbas F et al.·Journal of clinical medicine·2023

This study examined whether severe COVID-19 infection—particularly high fever and low oxygen levels—can trigger lasting fatigue, depression, and anxiety through inflammation and oxidative stress in the body. Researchers compared 86 long COVID patients with 39 healthy controls and found that about one-third of long COVID patients had very high signs of immune activation and cellular damage. The study suggests that the severity of initial COVID infection may predict who develops long-term symptoms through measurable changes in inflammatory markers.

NeuroinflammationImmune System

E2 ModerateCohortPEM unclear

Repetitive transcranial magnetic stimulation ameliorates symptoms in patients with myalgic encephalomyelitis (chronic fatigue syndrome).

Miwa, Kunihisa, Inoue, Yukichi·IBRO neuroscience reports·2023

This small study tested a brain stimulation treatment called repetitive transcranial magnetic stimulation (rTMS) in 30 ME/CFS patients. The treatment targeted specific areas of the brain involved in movement and decision-making. After treatment, most patients reported improvements in their ability to do daily activities, reduced dizziness when standing, better balance, and less pain.

Autonomic Nervous System

Myalgic Encephalomyelitis/Chronic Fatigue Syndrome in Adults: United States, 2021-2022.

Vahratian, Anjel, Lin, Jin-Mann S, Bertolli, Jeanne et al.·NCHS data brief·2023

This study looked at how many adults in the United States had ME/CFS during 2021-2022 by surveying a large, representative group of people. Researchers found that ME/CFS affects people across all ages, races, and ethnic groups. The study also showed that ME/CFS costs the U.S. economy between $18-51 billion each year.

E2 ModerateCohortPEM unclearCross-Sectional

Risk factors for suicidal ideation in a chronic illness.

Elliott, Meghan K, Jason, Leonard A·Death studies·2023

This study looked at why some people with ME/CFS experience suicidal thoughts. Researchers surveyed 559 people with ME/CFS and found that certain factors—including sleep problems, feeling stigmatized by others, loss of physical abilities, severe disability, and being unmarried—were associated with increased suicide risk. The findings suggest that better education about ME/CFS, reducing stigma, and developing effective treatments could help protect people with this illness.

Sleep

E2 ModerateCohortPEM unclearLongitudinal

A unique circular RNA expression pattern in the peripheral blood of myalgic encephalomyelitis/chronic fatigue syndrome patients.

Cheng, Yuning, Xu, Si-Mei, Takenaka, Konii et al.·Gene·2023

Researchers looked at a special type of genetic material called circular RNA (circRNA) in the blood of ME/CFS patients and healthy people, measuring it before and after exercise. They found that ME/CFS patients have a different pattern of circular RNAs compared to healthy controls, and unlike healthy people, ME/CFS patients didn't show the normal increase in these molecules after exercise. The study identified 14 specific circular RNAs that were present in ME/CFS patients but completely absent in healthy controls, suggesting these could potentially be used as markers to help diagnose the disease.

E2 ModerateCohortPEM unclearCross-Sectional

What lies beneath: White matter microstructure in pediatric myalgic encephalomyelitis/chronic fatigue syndrome using diffusion MRI.

Josev, Elisha K, Chen, Jian, Seal, Marc et al.·Journal of neuroscience research·2023

Researchers used advanced brain imaging to look for structural changes in the brains of teenagers recently diagnosed with ME/CFS compared to healthy peers. While teens with ME/CFS showed worse fatigue, pain, sleep quality, and cognitive problems like slower thinking speed, the brain scans did not reveal significant differences in white matter (the brain tissue that carries signals between brain regions). This suggests that early-stage ME/CFS in teenagers may not involve obvious structural brain changes, unlike what has been found in adult ME/CFS patients.

Typing myalgic encephalomyelitis by infection at onset: A DecodeME study.

Bretherick, Andrew D, McGrath, Simon J, Devereux-Cooke, Andy et al.·NIHR open research·2023

This large study asked over 17,000 people with ME/CFS about their symptoms, when their illness started, and what health conditions they experience. The researchers found that ME/CFS is not one-size-fits-all: people whose ME/CFS began after an infection (like COVID-19 or glandular fever) reported different patterns of symptoms and other health problems compared to those whose illness started without a clear infection. The study also confirmed that women are more affected by ME/CFS than men, and discovered that women tend to have more additional health conditions alongside ME/CFS.

Symptom-based clusters in people with ME/CFS: an illustration of clinical variety in a cross-sectional cohort.

Vaes, Anouk W, Van Herck, Maarten, Deng, Qichen et al.·Journal of translational medicine·2023

This study looked at whether people with ME/CFS can be grouped into different subtypes based on their specific combination of symptoms. Researchers asked 337 people with ME/CFS to report their symptoms and found 13 major groups, where people in each group shared similar patterns of symptom severity and frequency. While fatigue and post-exertional malaise (PEM) appeared in all groups, other symptoms varied—meaning people with ME/CFS experience the illness quite differently from one another.

E2 ModerateCohortPEM not requiredCross-Sectional

A cross-sectional study exploring the relationship between symptoms of anxiety/depression and P50 sensory gating in adult patients diagnosed with chronic fatigue syndrome/myalgic encephalomyelitis.

Liu, Xinyi, Liu, Sitong, Ren, Runtao et al.·Frontiers in neuroscience·2023

This study looked at 249 people with ME/CFS to understand how anxiety and depression relate to a specific brain activity pattern called P50 sensory gating. Researchers used questionnaires to measure anxiety and depression, and brain scans (EEG) to measure how well the brain filters out repetitive sounds. They found that abnormal filtering of sounds was linked to anxiety, depression, and fatigue severity.

E2 ModerateCohortPEM not requiredCross-Sectional

Medical assistance in dying when natural death is not reasonably foreseeable: Survey of providers' experiences with patients making track 2 requests.

Wiebe, Ellen, Kelly, Michaela·Canadian family physician Medecin de famille canadien·2023

This study looked at how doctors in Canada handled requests from patients with serious chronic illnesses who asked for medical assistance in dying (MAID) between March and September 2021. Among 54 patients who made these requests, about 15% had ME/CFS or similar complex chronic conditions, and 52% had chronic pain. Doctors reported struggling most with patients who also had mental health conditions and uncertainty about whether patients had tried all available treatments.

E2 ModerateCohortPEM not requiredObservational

A distinctive profile of family genetic risk scores in a Swedish national sample of cases of fibromyalgia, irritable bowel syndrome, and chronic fatigue syndrome compared to rheumatoid arthritis and major depression.

Kendler, Kenneth S, Rosmalen, Judith G M, Ohlsson, Henrik et al.·Psychological medicine·2023

This study looked at the family histories of over 5 million Swedish people to understand whether ME/CFS, fibromyalgia, and irritable bowel syndrome share common genetic roots. Researchers found that people with these conditions have a distinctive pattern of genetic risk that affects multiple body systems—including pain, mood, immune function, and sleep—rather than being limited to one specific area like depression or rheumatoid arthritis. This suggests these functional somatic disorders may arise from a complex genetic vulnerability affecting several interconnected systems rather than a single cause.

E2 ModerateBehavioralPEM not requiredCross-Sectional

Chronic fatigue syndrome in caregivers of children with cerebral palsy and affecting factors.

Pasin, Tugce, Karatekin, Bilinc Dogruoz, Pasin, Ozge·Northern clinics of Istanbul·2023

This study looked at mothers caring for children with cerebral palsy to see how many developed ME/CFS and what factors affected them. The researchers found that about 80% of the mothers met the clinical criteria for ME/CFS, with mothers who stayed home having more severe fatigue than those who worked full-time. The child's hand and arm function appeared to be an important factor in how severe the mother's fatigue became.

Sleep

E2 ModerateCohortPEM unclearLongitudinal

Characteristics of Persistent Symptoms Manifested after SARS-CoV-2 Vaccination: An Observational Retrospective Study in a Specialized Clinic for Vaccination-Related Adverse Events.

Tokumasu, Kazuki, Fujita-Yamashita, Manami, Sunada, Naruhiko et al.·Vaccines·2023

Researchers at a specialized clinic in Japan studied 121 patients who experienced long-lasting symptoms after receiving a COVID-19 vaccine. The most common symptoms were numbness or tingling sensations (28% of patients), extreme tiredness (25%), fever (17%), and headaches (17%). Some patients developed serious conditions including ME/CFS, and most symptoms started within a week of vaccination but lasted months or longer.

Investigating the factors associated with meaningful improvement on the SF-36-PFS and exploring the appropriateness of this measure for young people with ME/CFS accessing an NHS specialist service: a prospective cohort study.

Gaunt, Daisy, Brigden, Amberly, Metcalfe, Chris et al.·BMJ open·2023

This study followed 193 young people with ME/CFS at a UK NHS specialist service to see how many improved over 6-12 months and what factors predicted improvement. About 40% showed meaningful improvement at 6 months, rising to 54% at 12 months. Interestingly, young people who started with worse physical function scores were actually more likely to show improvement, but very few other patient characteristics predicted who would get better.

Exploring the joint potential of inflammation, immunity, and receptor-based biomarkers for evaluating ME/CFS progression.

Berkis, Uldis, Svirskis, Simons, Krumina, Angelika et al.·Frontiers in immunology·2023

This study looked for blood markers that could help doctors understand how severe ME/CFS is and track disease progression. Researchers measured inflammation-related proteins, immune system components, and antibodies against nerve receptors in blood samples from healthy people and patients with mild, moderate, and severe ME/CFS. They found that certain markers—especially antibodies against beta2-adrenergic and M4 receptors, along with specific immune proteins—showed promise for distinguishing disease severity, with over 90% accuracy in identifying who has ME/CFS versus who is healthy.

BiomarkersImmune System