ME/CFS Evidence Browser — Classified Studies on Myalgic Encephalomyelitis

421–440 of 729 studies

E2 ModerateCohortPEM not requiredCross-Sectional

Influence of exhaustive treadmill exercise on cognitive functioning in chronic fatigue syndrome.

LaManca, J J, Sisto, S A, DeLuca, J et al.·The American journal of medicine·1998

This study looked at how exercise affects thinking and mental processing in people with ME/CFS compared to healthy people. Both groups did exhausting exercise on a treadmill, then took thinking tests right after and 24 hours later. People with ME/CFS performed worse on these thinking tests after exercise, particularly on tasks involving speed and attention, and their thinking stayed impaired the next day.

Post-Exertional Malaise

E2 ModerateCohortPEM unclearObservational

Physical activity before and after exercise in women with chronic fatigue syndrome.

Sisto, S A, Tapp, W N, LaManca, J J et al.·QJM : monthly journal of the Association of Physicians·1998

This study tracked the physical activity of 20 women with ME/CFS and 20 healthy volunteers for two weeks using a movement monitor worn at the waist. After all participants did a strenuous treadmill exercise test, researchers measured how their activity changed. Women with ME/CFS showed a noticeable drop in activity levels after the exercise, with the biggest decrease happening around days 12-14, and they took more rest breaks during the day.

Post-Exertional Malaise

E2 ModerateCohortPEM not requiredCross-Sectional

Muscle fibre characteristics and lactate responses to exercise in chronic fatigue syndrome.

Lane, R J, Barrett, M C, Woodrow, D et al.·Journal of neurology, neurosurgery, and psychiatry·1998

Researchers examined muscle samples from 105 ME/CFS patients to understand why they have abnormal responses to exercise, particularly high lactate levels. They found that patients with high lactate responses had fewer type 1 muscle fibres (which are energy-efficient), but this wasn't because they were inactive—it appeared to be a specific muscle problem related to ME/CFS itself.

Post-Exertional Malaise

E2 ModerateBehavioralPEM not requiredCross-Sectional

Physical fatigability and exercise capacity in chronic fatigue syndrome: association with disability, somatization and psychopathology.

Fischler, B, Dendale, P, Michiels, V et al.·Journal of psychosomatic research·1997

This study looked at how people with ME/CFS respond to exercise by measuring whether they can reach their target heart rate during activity. Researchers found that many patients don't reach expected heart rates and that this relates to how disabled they feel in daily life. Interestingly, anxiety and depression didn't explain why people avoided strenuous exercise, suggesting that avoidance behavior in ME/CFS may have different causes than in other conditions.

Post-Exertional Malaise

E2 ModerateCohortPEM not requiredCase-Control

A case-control study to assess possible triggers and cofactors in chronic fatigue syndrome.

MacDonald, K L, Osterholm, M T, LeDell, K H et al.·The American journal of medicine·1996

This study compared 47 people with ME/CFS to 47 matched healthy controls to identify what might trigger or contribute to the illness. Researchers found that people with ME/CFS were more likely to have exercised regularly before getting sick, and women with ME/CFS were more likely to have never had children. Depression was more common after ME/CFS developed, though it wasn't more common before illness onset.

Post-Exertional Malaise

E2 ModerateCohortPEM not requiredCross-Sectional

Metabolic and cardiovascular effects of a progressive exercise test in patients with chronic fatigue syndrome.

Sisto, S A, LaManca, J, Cordero, D L et al.·The American journal of medicine·1996

Researchers tested how well women with ME/CFS could exercise compared to healthy controls by having them walk on a treadmill until exhaustion. Women with ME/CFS had lower aerobic fitness levels than healthy controls, but their hearts and lungs appeared to work normally. Importantly, the maximal exercise test did not cause a major flare-up of fatigue or other ME/CFS symptoms.

Post-Exertional Malaise

E2 ModerateCohortPEM not requiredCase-Control

An examination of the working case definition of chronic fatigue syndrome.

Komaroff, A L, Fagioli, L R, Geiger, A M et al.·The American journal of medicine·1996

Researchers studied 281 patients with severe, long-lasting fatigue to see how well the official definition of ME/CFS worked. They compared these patients to healthy people and people with similar conditions like multiple sclerosis and depression. The study found that certain symptoms—like muscle pain, post-exertion exhaustion, headaches, and flu-like symptoms—were very common in ME/CFS patients but rare in the other groups.

Post-Exertional Malaise

E2 ModerateCohortPEM requiredCross-Sectional

Decreased vagal power during treadmill walking in patients with chronic fatigue syndrome.

Cordero, D L, Sisto, S A, Tapp, W N et al.·Clinical autonomic research : official journal of the Clinical Autonomic Research Society·1996

This study compared how the nervous system controls heart rate in people with ME/CFS versus healthy volunteers during and after treadmill walking. Researchers found that people with ME/CFS had weaker parasympathetic (rest-and-recover) nervous system activity during walking, and this activity dropped even further after exercise stopped. This abnormality might help explain why ME/CFS patients feel worse after physical activity.

Post-Exertional Malaise

E2 ModerateBehavioralPEM not requiredCase-Control

Psychological symptoms, somatic symptoms, and psychiatric disorder in chronic fatigue and chronic fatigue syndrome: a prospective study in the primary care setting.

Wessely, S, Chalder, T, Hirsch, S et al.·The American journal of psychiatry·1996

This study followed over 1,900 people in primary care and found that most individuals with ME/CFS also had a current mental health condition like depression or anxiety. The researchers discovered that people with chronic fatigue were much more likely to have psychiatric disorders (60-78%) compared to those without fatigue (19-31%). While the study suggests a strong link between psychiatric conditions and ME/CFS, it does not explain whether one causes the other.

Post-Exertional Malaise

E2 ModerateBehavioralPEM not requiredCross-Sectional

The impact of catastrophic beliefs on functioning in chronic fatigue syndrome.

Petrie, K, Moss-Morris, R, Weinman, J·Journal of psychosomatic research·1995

This study looked at whether how people think about ME/CFS affects how disabled they become. Researchers asked 282 people with ME/CFS what they thought would happen if they pushed themselves too hard, and sorted their answers into catastrophic (very negative) or non-catastrophic thinking. People who had catastrophic thoughts about pushing themselves were significantly more fatigued and more disabled in work, household tasks, sleep, socializing, and hobbies—even though they had been sick for similar lengths of time as others.

Post-Exertional Malaise

E2 ModerateCohortPEM not requiredCross-Sectional

Repetitively negative changing T waves at 24-h electrocardiographic monitors in patients with the chronic fatigue syndrome. Left ventricular dysfunction in a cohort.

Lerner, A M, Lawrie, C, Dworkin, H S·Chest·1993

This study looked at heart activity recorded over 24 hours in ME/CFS patients compared to others. All 24 ME/CFS patients showed unusual patterns on their heart monitors (abnormal T waves), compared to only 22% of people without ME/CFS. Further testing found that 8 out of 60 ME/CFS patients had mild heart pumping problems that only showed up during exercise, even though their resting heart function appeared normal. The researchers suggest ME/CFS fatigue might be related to the heart not working well during normal daily activities.

Post-Exertional Malaise

E2 ModerateReviewPEM unclearReview-Narrative

Symptoms and signs of chronic fatigue syndrome.

Komaroff, A L, Buchwald, D·Reviews of infectious diseases·1991

This review summarizes what doctors have learned about chronic fatigue syndrome (ME/CFS) by studying approximately 510 patients. The hallmark features include a sudden illness-like onset, long-lasting exhaustion that severely limits daily activities, and a unique symptom called postexertional malaise—where patients feel much worse after physical or mental activity. Many patients also experience fever, sore throat, swollen lymph nodes, muscle pain, sleep problems, and difficulty concentrating.

Post-Exertional Malaise

E2 ModerateCohortPEM unclearCross-Sectional

Aerobic work capacity in patients with chronic fatigue syndrome.

Riley, M S, O'Brien, C J, McCluskey, D R et al.·BMJ (Clinical research ed.)·1990

This study tested how much physical activity patients with ME/CFS could manage on a treadmill and compared them to healthy people and those with irritable bowel syndrome. Researchers found that ME/CFS patients got tired much faster, had higher heart rates during exercise, and felt like they were working much harder than the other groups—even though they weren't doing as much activity.

Post-Exertional Malaise

E2 ModerateCohortPEM not requiredCross-Sectional

Cardiac function at rest and with exercise in the chronic fatigue syndrome.

Montague, T J, Marrie, T J, Klassen, G A et al.·Chest·1989

This study looked at heart function in 41 ME/CFS patients compared to healthy volunteers. While the hearts looked normal at rest, patients became exhausted during exercise much sooner than healthy people—their heart rates climbed more slowly and didn't reach the expected levels, even though their resting heart rhythms and structure were completely normal.

Post-Exertional Malaise

E3 PreliminaryCohortPEM unclearObservational

Treatment of post-COVID symptoms with auricular vagus nerve stimulation.

Gebetsroither, Patrick, Ettenauer, Thomas, Likar, Rudolf·Wiener medizinische Wochenschrift (1946)·2026

Researchers tested a treatment called auricular vagus nerve stimulation (mild electrical stimulation applied to the ear) in 9 patients with long COVID symptoms. After 4 weeks of treatment, patients reported improvement in 28 out of 35 symptoms they were tracked for, with particular benefits for pain, fatigue, exhaustion after activity, sleep problems, and heart/blood pressure irregularities. Many of these improvements lasted when patients were checked again 12 weeks later.

Post-Exertional Malaise

E3 PreliminaryMechanismPEM required

From fatigue to physiology: Submaximal 2-day cardiopulmonary exercise test and emerging standards in long COVID.

Risbano, Michael G·Experimental physiology·2026

This study examines how a special two-day exercise test can help doctors understand the physical changes that happen in long COVID and ME/CFS patients. Instead of pushing patients to their maximum effort, researchers used a gentler approach to measure heart and lung function, which may be safer and more revealing for people with these conditions. The study aims to create new standard ways of testing that better capture what's happening in patients' bodies.

Post-Exertional Malaise

E3 PreliminaryReviewPEM unclearReview-Narrative

Molecular hydrogen as a treatment for ME/CFS: a mini-review of clinical evidence and mechanistic rationale.

Friedberg, Fred, LeBaron, Tyler W·Frontiers in medicine·2026

This review examines whether hydrogen-rich water might help ME/CFS patients. Hydrogen is a simple molecule that may reduce inflammation and improve energy production in cells—two problems linked to ME/CFS. Early studies show it may help reduce fatigue and improve daily functioning with few side effects, though the research is still very limited.

Post-Exertional Malaise

E3 PreliminaryReviewPEM unclearReview-Narrative

Physiotherapy management of long COVID in adults.

Nygren-Bonnier, Malin, Holland, Anne E·Journal of physiotherapy·2026

This study examines how physical therapy and rehabilitation approaches can help adults with long COVID manage their symptoms and improve function. The review looks at different physiotherapy strategies that healthcare providers use to treat long COVID patients. Understanding which approaches work best can help patients and doctors make better decisions about treatment options.

Post-Exertional Malaise

E3 PreliminaryMechanismPEM requiredMechanistic

Genetic depletion of the early autophagy protein ATG13 impairs mitochondrial energy metabolism, augments oxidative stress, induces the polarization of macrophages to the M1 inflammatory mode, and compromises myelin integrity in skeletal muscle.

Toriola, Mubaraq A, Timlin, Emma, Bulbule, Sarojini et al.·Inflammation research : official journal of the European Histamine Research Society ... [et al.]·2026

This study examined a protein called ATG13 that helps cells clean up damaged parts, particularly in immune cells called macrophages. When ATG13 was reduced, these immune cells couldn't work properly, their energy-producing structures (mitochondria) became dysfunctional, and they created too much harmful oxidative stress. This triggered the immune cells to switch into an inflammatory state and caused muscle weakness and nerve damage in a mouse model.

Immune SystemPost-Exertional Malaise

E3 PreliminaryCommentaryPEM requiredEditorial

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.

Energy MetabolismImmune SystemPost-Exertional Malaise

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Influence of exhaustive treadmill exercise on cognitive functioning in chronic fatigue syndrome.

Physical activity before and after exercise in women with chronic fatigue syndrome.

Muscle fibre characteristics and lactate responses to exercise in chronic fatigue syndrome.

Physical fatigability and exercise capacity in chronic fatigue syndrome: association with disability, somatization and psychopathology.

A case-control study to assess possible triggers and cofactors in chronic fatigue syndrome.

Metabolic and cardiovascular effects of a progressive exercise test in patients with chronic fatigue syndrome.

An examination of the working case definition of chronic fatigue syndrome.

Decreased vagal power during treadmill walking in patients with chronic fatigue syndrome.

Psychological symptoms, somatic symptoms, and psychiatric disorder in chronic fatigue and chronic fatigue syndrome: a prospective study in the primary care setting.

The impact of catastrophic beliefs on functioning in chronic fatigue syndrome.

Repetitively negative changing T waves at 24-h electrocardiographic monitors in patients with the chronic fatigue syndrome. Left ventricular dysfunction in a cohort.

Symptoms and signs of chronic fatigue syndrome.

Aerobic work capacity in patients with chronic fatigue syndrome.

Cardiac function at rest and with exercise in the chronic fatigue syndrome.

Treatment of post-COVID symptoms with auricular vagus nerve stimulation.

From fatigue to physiology: Submaximal 2-day cardiopulmonary exercise test and emerging standards in long COVID.

Molecular hydrogen as a treatment for ME/CFS: a mini-review of clinical evidence and mechanistic rationale.

Physiotherapy management of long COVID in adults.

Genetic depletion of the early autophagy protein ATG13 impairs mitochondrial energy metabolism, augments oxidative stress, induces the polarization of macrophages to the M1 inflammatory mode, and compromises myelin integrity in skeletal muscle.

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

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