ME/CFS Science
@mecfsskeptic.bsky.social
2.3K followers 150 following 1.5K posts
In-depth analysis of research on myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS). Formerly known as ME/CFS Skeptic. https://mecfsscience.org/
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mecfsskeptic.bsky.social
Don't think there is much scientific evidence on it, mostly patients sharing their experiences.

Suspect that HR monitoring is mostly helpful to people who get PEM from too much physical activity. But for pacing other tasks such as socialising or reading, it seems less useful.
mecfsskeptic.bsky.social
9) Some are concerned that pacing may lead to decreased activity levels but the accelerometer data showed that it largely remained the same in both the intervention and control group.

(only) 1 Long Covid patient reported anxiety from monitoring their HR limit with alarms.
mecfsskeptic.bsky.social
8 ) There were also no discernible changes in the blood pressure, heart rate, and oxygen saturation measures before and after the intervention. Both the control (3.7–2.7) and intervention groups (3.7–2.9) showed decreased levels of lactate.
mecfsskeptic.bsky.social
7) The outcome measures are hard to interpret because the authors don't report variability or statistical tests. But it seems that there weren't notable differences between groups in for example fatigue or physical functioning.
mecfsskeptic.bsky.social
6) The results: the trial and its many measurements were doable, there weren't many dropouts or issues. Some participants did find it hard to fill in a PEM diary for 2 months and five ME/CFS patients didn't tolerate the standing test.
mecfsskeptic.bsky.social
5) All these measurements and interventions were carried out in the participants’ homes.

Patients were mainly recruited from social media but it was difficult to find sufficient Long Covid participants (as many were already using a heart rate monitor).
mecfsskeptic.bsky.social
4) The most fascinating aspect of this trial is that it measured multiple objective outcomes: a 10-minute standing test (for POTS), an accelerometer for activity levels, a FirstBeat bodyguard to measure physiological stress and recovery, and a device that measured lactate.
mecfsskeptic.bsky.social
3) The device gave an alarm notification when patients exceeded their chosen heart rate limit. Patients in the control group got pacing sessions but without the use of a heart rate monitor.

The trial lasted for 8 weeks.
mecfsskeptic.bsky.social
2) Pacing is a way to manage activities to avoid post-exertional malaise.

Patients in the intervention group got a wrist-based Garmin device or an arm-based strap with the Visible app. Their heart rate limit was calculated using personalised formulas such as: (220-Age) × 0.6
mecfsskeptic.bsky.social
1) The Physios for ME team published a randomized trial on pacing with a heart rate monitor. It included 32 patients with ME/CFS and 15 with Long Covid.

A brief breakdown of the main results 🧵
Reposted by ME/CFS Science
cgatist.bsky.social
The research used to claim reliability of a ME/CFS blood test has important limitations, shown here.

www.theguardian.com/society/2025...
Three possible confounders in a study proposing an ME/CFS blood test : sex/age, batch and inactivity/severity. Better designed studies by independent researchers are necessary.
mecfsskeptic.bsky.social
9) The study is question is:

Hunter et al. 2025. Development and validation of bloodbased diagnostic biomarkers for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) using EpiSwitch® 3-dimensional genomic regulatory immuno-genetic profiling.
Development and validation of blood-based diagnostic biomarkers for Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) using EpiSwitch® 3-dimensional genomic regulatory immuno-genetic profiling - Journal of Translational Medicine
Myalgic Encephalomyelitis/Chronic Fatigue Syndrome (ME/CFS) is a debilitating, multifactorial disorder characterised by profound fatigue, post-exertional malaise, cognitive impairments, and autonomic dysfunction. Despite its significant impact on quality of life, ME/CFS lacks definitive diagnostic biomarkers, complicating diagnosis and management. Recent evidence highlights potential blood tests for ME/CFS biomarkers in immunological, genetic, metabolic, and bioenergetic domains. Chromosome conformations (CCs) are potent epigenetic regulators of gene expression and cross-tissue exosome signalling. We have previously developed an epigenetic assay, EpiSwitch®, that employs an algorithm-based CCs analysis. Using EpiSwitch® technology, we have shown the presence of disease-specific CCs in peripheral blood mononuclear cells (PBMCs) of patients with amyotrophic lateral sclerosis (ALS), rheumatoid arthritis (RA), prostate and colorectal cancers, diffuse Large B-cell lymphoma and severe COVID-19. In a recent paper, we have identified a profile of systemic chromosome conformations in cancer patients reflective of the predisposition to respond to immune checkpoint inhibitors, PD-1/PD-L1 antagonists, with 85% accuracy. In this Retrospective case/control study (EPI-ME, Epigenetic Profiling Investigation in Myalgic Encephalomyelitis), we used whole blood samples retrospectively collected from n = 47 patients with severe ME/CFS and n = 61 age-matched healthy control patients to perform whole-genome 3D DNA screening for CCs correlating to ME/CFS diagnosis. We identified a 200-marker model for ME/CFS diagnosis (Episwitch®CFS test). First testing on the retrospective independent validation cohort demonstrated a strong systemic ME/CFS signal with a sensitivity of 92% and a specificity of 98%.Pathways analysis revealed several likely contributors to the pathology of ME/CFS, including interleukins, TNFα, neuroinflammatory pathways, toll-like receptor signalling and JAK/STAT. Comparison with pathways involved in the action of Rituximab and glatiramer acetate (Copaxone) (therapies with potential in ME/CFS treatment) identified IL2 as a shared pathway with clear patient clustering, indicating a possibility of a potential responder group for targeted treatment.
translational-medicine.biomedcentral.com
mecfsskeptic.bsky.social
8 ) The epigenetic test might be interesting but it needs to be done on larger and better samples to avoid confounding by sex, activity levels, databases, etc.

We aren't the only ones with reservations, see these comments by experts on the SMC:
www.sciencemediacent...
mecfsskeptic.bsky.social
7) The pathway that stood out the most involved Interleukin-2 (IL-2).

The authors suggest that this can be used to subgroup patients and they propose twelve therapies that target this pathway (some such as Rituximab and Rapamycin have already been trialled in ME/CFS).
mecfsskeptic.bsky.social
6) The researchers highlight that their results "suggest a strong immunological component in ME/CFS pathology." They found overlap with pathways implicated in multiple sclerosis, rheumatoid arthritis and other chronic inflammatory disorders.
mecfsskeptic.bsky.social
5) The model had an accuracy of 96%: it correctly classified 22 out of 23 ME/CFS patients and 44 out of 46 controls.

ME/CFS, however, is likely a heterogenous syndrome so 100% accuracy should not be the main goal of such a test (it should be to find relevant pathology).
mecfsskeptic.bsky.social
4) While patient samples were taken from the ME/CFS biobank, controls mainly came from the OBD database.

Deconditioning and activity patterns may also be a confounder: ME/CFS patients were severely ill and housebound while all controls were healthy and likely physically active.
mecfsskeptic.bsky.social
3) The sample size, for example, was really small. They trained their machine-learning model with 200 parameters on only 23 ME/CFS patients.

Controles were also not matched for sex: 82% of patients were female compared to only 36% of controls.
mecfsskeptic.bsky.social
2) Unfortunately, the study itself doesn't warrant the hype. It comes from the company Oxford BioDynamics (OBD), that developed a new epigenetic test called EpiSwitch which they now applied to ME/CFS.

There are lots of limitations...
mecfsskeptic.bsky.social
1) There's a new ME/CFS study that is getting a lot of attention in the media. It focuses on epigenetics: how genes are switched on or off by folding DNA in a different way.

You genetic code itself is fixed but the expression of genes can change by environmental factors.
mecfsskeptic.bsky.social
Not really. I think this group developed this tracer and suspected it might be relevant in Long Covid.
mecfsskeptic.bsky.social

8) Here's the link to the paper:

Fujimoto et al. 2025. Systemic increase of AMPA receptors associated with cognitive impairment of long COVID.
academic.oup.com/bra...