Evidence browser

Heterogeneity in Measures of Illness among Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Is Not Explained by Clinical Practice: A Study in Seven U.S. Specialty Clinics.

Unger, Elizabeth R, Lin, Jin-Mann S, Chen, Yang et al.·Journal of clinical medicine·2024

Researchers studied 465 ME/CFS patients across seven specialized clinics in the United States to see if doctors diagnosed and recognized the same disease. They found that while the clinics had similar patients, there was tremendous variation in how sick individual patients were—some had mild symptoms while others were severely affected. This suggests that ME/CFS may naturally come in many different forms, and understanding these differences could help improve research and treatment.

E2 ModerateCohortPEM unclearObservational

Resonant breathing improves self-reported symptoms and wellbeing in people with Long COVID.

Polizzi, Jessica, Tosto-Mancuso, Jenna, Tabacof, Laura et al.·Frontiers in rehabilitation sciences·2024

This study looked at whether slow, controlled breathing (called resonant breathing) could help people with Long COVID feel better. Ninety-nine people with Long COVID tried a resonant breathing program and reported their symptoms before and after. Most people said they felt better overall, especially in areas like stress control, focus, breathing ability, and sleep quality.

E2 ModerateCohortPEM unclearCross-Sectional

Association of physical symptoms with accelerometer-measured movement behaviors and functional capacity in individuals with Long COVID.

Rosa-Souza, Francisco José, Freire, Yuri Alberto, Galliano, Leony Morgana et al.·Scientific reports·2024

This study looked at 102 people with Long COVID to understand how specific symptoms affect their ability to move and be physically active. Researchers used activity trackers to measure daily movement and tested how far people could walk and how quickly they could stand up from a chair. They found that fatigue and post-exertional malaise (feeling worse after activity) were linked to lower daily step counts, while shortness of breath was linked to poorer performance on physical tests.

E2 ModerateBehavioralPEM unclearObservational

Outpatient group therapy for post-COVID patients - a naturalistic feasibility study of a face-to-face and online group concept.

Zimmermann-Schlegel, Verena, Gronewold, Nadine, Stengel, Sandra et al.·Frontiers in psychiatry·2024

Researchers created and tested a group therapy program for people with Post-COVID syndrome that meets weekly for 8 sessions to help manage fatigue, stress sensitivity, and other symptoms. The program was offered both in-person and online to 57 patients, and most participants found it helpful, especially valuing the chance to connect with others experiencing similar challenges. The results suggest this type of group therapy is safe and acceptable, with the online format being particularly useful for people who have difficulty leaving home.

An Adaptive Pacing Intervention for Adults Living With Long COVID: A Narrative Study of Patient Experiences of Using the PaceMe app.

Meach, Rachel, Carless, David, Sanal-Hayes, Nilihan E M et al.·Journal of patient experience·2024

This study looked at how a smartphone app called PaceMe helps people with long COVID manage their symptoms by balancing activity with rest. Twenty-five people used the app and were interviewed about their experience after 3-6 months. The app helped participants better understand and manage post-exertional malaise (the worsening of symptoms after activity), feel supported, and feel more in control of their condition.

E2 ModerateCohortPEM unclearCross-Sectional

The Head-Up Tilt Table Test as a Measure of Autonomic Functioning among Patients with Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Jason, Leonard A, McGarrigle, William J, Vermeulen, Ruud C W·Journal of personalized medicine·2024

This study tested 193 people with ME/CFS using a tilt table test to check if they had problems with their autonomic nervous system (the system that controls heart rate and blood pressure). About one in three participants showed signs of orthostatic intolerance—a condition where the body struggles to maintain proper blood pressure and heart rate when standing. People with these problems reported worse sleep, more severe post-exertional malaise (exhaustion after activity), and greater physical limitations.

E2 ModerateCohortPEM unclearLongitudinal

Three-Month Follow-Up of the Post-COVID Syndrome after Admission to a Specialised Post-COVID Centre-A Prospective Study Focusing on Mental Health with Patient Reported Outcome Measures (PROMs).

Schäfer, Isabel Cecil, Krehbiel, Johannes, Adler, Werner et al.·International journal of environmental research and public health·2024

Researchers followed 265 Post-COVID patients for about 5 months to understand how mental health symptoms changed over time. They found that most patients still had severe Post-COVID symptoms, with nearly 9 in 10 reporting extreme fatigue and about half experiencing depression. Importantly, while depression and anxiety improved somewhat over time, fatigue and post-exertional malaise (getting worse after activity) stayed at very high levels and did not improve.

E2 ModerateGuidelinePEM unclearGuideline

Practical Recommendations for Exercise Training in Patients with Long COVID with or without Post-exertional Malaise: A Best Practice Proposal.

Gloeckl, Rainer, Zwick, Ralf H, Fürlinger, Ulrich et al.·Sports medicine - open·2024

This study created practical guidelines for exercise training in people with long COVID, especially those who experience post-exertional malaise (PEM)—when symptoms get worse after physical activity. The researchers reviewed 46 previous studies and surveyed 14 international experts to develop three different exercise approaches depending on whether someone has no PEM, mild/moderate PEM, or severe PEM. These guidelines aim to help healthcare professionals safely design exercise programs tailored to each person's specific situation.

Cardiopulmonary and metabolic responses during a 2-day CPET in myalgic encephalomyelitis/chronic fatigue syndrome: translating reduced oxygen consumption to impairment status to treatment considerations.

Keller, Betsy, Receno, Candace N, Franconi, Carl J et al.·Journal of translational medicine·2024

This study tested 84 people with ME/CFS and 71 healthy controls on an exercise bike on two days, 24 hours apart. People with ME/CFS performed worse on the second day of testing—their oxygen use, heart rate, and exercise capacity all declined—while healthy people stayed about the same. This objective decline mirrors the real-world experience of post-exertional malaise, where ME/CFS patients feel worse after physical activity.

Post‑recovery symptoms of infected cases after Omicron pandemic: a quick online cross-sectional study based on C19-YRSm in China.

Ye, Xiao-Lei, Zhang, Ying, Dai, Xin-Hua et al.·BMC public health·2024

This study surveyed 753 Chinese residents who had been infected with the Omicron variant of COVID-19 to understand what symptoms they experienced during recovery. Researchers found that nearly half reported persistent breathlessness and cognitive problems (trouble thinking clearly), while about one-third experienced fatigue that didn't improve with rest, anxiety, or pain. Most people recovered within four months, and less than 10% reported serious difficulties with daily activities.

E2 ModerateCohortPEM unclearCross-Sectional

Prevalence and determinants of post-acute sequelae after SARS-CoV-2 infection (Long COVID) among adults in Mexico during 2022: a retrospective analysis of nationally representative data.

Bello-Chavolla, Omar Yaxmehen, Fermín-Martínez, Carlos A, Ramírez-García, Daniel et al.·Lancet regional health. Americas·2024

This study looked at how many adults in Mexico experienced long-lasting symptoms after COVID-19 infection in 2022. Researchers found that about 1 in 5 people who had COVID-19 reported ongoing problems like fatigue, muscle pain, brain fog, and loss of taste or smell. The study showed that people who caught COVID-19 multiple times, had depression, or lived in poorer areas were more likely to develop these long-term symptoms, while vaccination and infection with newer variants reduced risk.

E2 ModerateCohortPEM not requiredCross-Sectional

An online survey among convalescents 5 months post SARS-CoV-2 infection in China.

Wang, Yalan, Liu, Maoshun, Guo, Yuanyuan et al.·Biosafety and health·2024

This study surveyed over 5,500 people in China about five months after they had COVID-19 to see what long-term health problems they experienced. The most common complaints were fatigue (tiredness), memory problems, post-exertional malaise (feeling much worse after physical activity), and brain fog. People with certain pre-existing conditions like heart disease, autoimmune diseases, or asthma were more likely to have moderate to severe symptoms.

E2 ModerateBehavioralPEM not requiredCross-Sectional

The association between Long-COVID symptomology, perceived symptom burden and mental health in COVID-19 patients in Shijiazhuang, China: a population-based health survey.

Li, Yufei, Lam, Lawrence T, Xiao, Ying et al.·Frontiers in psychiatry·2024

This study looked at 25% of COVID-19 patients in China who had symptoms lasting longer than two months after infection. Researchers found that patients with more Long-COVID symptoms—especially fatigue and post-exertional malaise (feeling worse after activity)—were more likely to experience depression and anxiety. The more severe patients felt their symptoms were, the greater their mental health struggles.

E2 ModerateCohortPEM unclearLongitudinal

Muscle abnormalities worsen after post-exertional malaise in long COVID.

Appelman, Brent, Charlton, Braeden T, Goulding, Richie P et al.·Nature communications·2024

This study looked at muscle tissue changes in long COVID patients, particularly focusing on post-exertional malaise (PEM)—the worsening of fatigue and pain after activity. Researchers found that muscles in long COVID patients showed structural damage, metabolic problems, and unusual deposits that got worse after activity triggered PEM. These findings help explain why exertion makes symptoms worse in some long COVID patients.

Energy MetabolismPost-Exertional Malaise

A Single-Center Pilot Study of Therapeutic Apheresis in Patients with Severe Post-COVID Syndrome.

Korth, Johannes, Steenblock, Charlotte, Walther, Romy et al.·Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme·2024

This small study looked at whether a blood-filtering treatment called apheresis could help 20 people with long COVID symptoms similar to ME/CFS. The researchers found that the treatment reduced harmful antibodies in patients' blood and many patients reported feeling better, with less fatigue, muscle pain, and post-exertional malaise. While these results are promising, the study was small and didn't use a control group, so we need larger tests to confirm whether the treatment truly works.

Fatigue and symptom-based clusters in post COVID-19 patients: a multicentre, prospective, observational cohort study.

Cornelissen, Merel E B, Bloemsma, Lizan D, Vaes, Anouk W et al.·Journal of translational medicine·2024

This study followed 95 Dutch patients with long COVID for up to 18 months after their initial SARS-CoV-2 infection. Most patients experienced persistent fatigue, along with sleep problems, pain, and cognitive difficulties. Interestingly, over half of these patients met the diagnostic criteria for ME/CFS, and their symptom patterns resembled those seen in people with ME/CFS.

Impaired Hand Grip Strength Correlates with Greater Disability and Symptom Severity in Post-COVID Myalgic Encephalomyelitis/Chronic Fatigue Syndrome.

Paffrath, Anna, Kim, Laura, Kedor, Claudia et al.·Journal of clinical medicine·2024

Researchers tested hand grip strength in 144 women with long-COVID symptoms, comparing those who met strict ME/CFS criteria (78 patients) with those who had other long-COVID symptoms. People with ME/CFS showed weaker grip strength and more severe disability, fatigue, and symptom worsening after activity compared to other long-COVID patients. Weak grip strength appeared to be connected to the core symptoms that define ME/CFS, suggesting muscle weakness in ME/CFS may share a common cause with other hallmark symptoms.

E2 ModerateCohortPEM unclearLongitudinal

Long-term COVID-19 sequelae by Theta and SARS-CoV-2 variants in a Philippine cohort.

Saloma, Cynthia P, Ayes, Marc Edsel C, Taracatac, Paolo S et al.·Frontiers in medicine·2024

This study followed people in the Philippines who had COVID-19 to see how long their symptoms lasted and whether different COVID variants caused different long-term problems. Researchers checked in with patients three times over a year and found that most people (68-88%) still had symptoms months after infection, with fatigue, brain fog, and headaches being the most common. The good news was that symptoms generally improved over time, though many people continued to struggle with debilitating effects.

A pilot cross-sectional investigation of symptom clusters and associations with patient-reported outcomes in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome and Post COVID-19 Condition.

Weigel, Breanna, Eaton-Fitch, Natalie, Thapaliya, Kiran et al.·Quality of life research : an international journal of quality of life aspects of treatment, care and rehabilitation·2024

This study compared people with ME/CFS and people with Long COVID to understand how their symptoms affect quality of life and daily functioning. Researchers found that both groups experience similar symptom patterns, particularly autonomic symptoms like breathing problems, which have the biggest impact on wellbeing. The findings suggest that Long COVID and ME/CFS may be closely related conditions, and that some people recovering from COVID-19 may develop ME/CFS-like illness over time.